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518 Cards in this Set
- Front
- Back
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What does deep fascia of the neck form
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A series of cylindrical compartments
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How is deep fascia of the neck arranged
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Investing layer of deep fascia
Prevertebral fascia Pretracheal fascia Carotid sheaths |
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Prevertebral fascia - what does it enclose
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Encloses vertebral column and associated muscles
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Pretracheal fascia - what does it enclose
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Encloses visceral compartment
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Carotid sheaths
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Enclose vascular compartment
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Where is the hyoid bone
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Angle of neck
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Where is the thyroid cartilage
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2 laminae fused in anterior midline as laryngeal prominence
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Where is cricoid cartilage
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At level of Cv6
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SCM
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Principle muscular landmark of neck
Divides neck anterior to trap into posterior and anterior cervical triangles Passes from manubrium of sternum and medial 1/3 of clavicle to mastoid process of temporal bone and superior nuchal line |
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What does the SCM doe
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Unilaterally - draws mastoid process anteriorly and inferiorly, rotating face to contralateral side
B/L - draws head forward and chin up Accessory muscle of respiration |
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What is the SCM innervated by and what provides its proprioceptive fibers
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Accessory nerve (CN XI) with proprioceptive fibers from anterior ramus of C2
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Congenital or spasmodic torticolis
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Congenital or spasmodic shortening/contraction of SCM, positions head to side
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Boundaries of posterior cervical triangle
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Posterior border of SCM
Anterior border of trap Middle 1/3 of clavicle |
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Roof of posterior cervical triangle
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Investing layer of deep cervical fascia
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Floor of posterior cervical triangle
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Prevertebral fascia and subjacent muscles
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What muscle subdivides the posterior cervical triangle
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Inferior belly of omohyoid muscle divides it into:
Occipital triangle and supraclavicular (subclavian) triangle |
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Where are the muscles in the floor of the posterior triangle
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Immediately deep to prevertebral fascia
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What are the muscles of the floor of the posterior tiriangle
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Splenius capitis
Levator scapulae Posterior scalene Middle scalene Anterior scalene |
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What is the platysma muscle for
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Facial expression
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What does the platysma develop from
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2nd pharyngeal arch
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What innervates the platysma
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Nerve of 2nd pharyngeal arch - facial nerve (CN VII)
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Where is the platysma
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Passes from pectoral fascia to inferior border of mandible and lower facial muscles
Crosses posterior and anterior cervical triangles within superficial fascia |
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Where are the external jugular and cutaneous branches of cervical plexus
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Deep to platysma within the superficial fascia overlying the SCM and posterior triangle
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Formation of external jugular
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Near angle of mandible
By union of retromandibular vein and posterior auricular vein |
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Where does the external jugular descend
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vertically across SCM to pierce the investing layer of deep cervical fascia to enter the subclavian vein
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What happens if the external jugular is cut where it pierces the investing fascia
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A venous air embolism may obstruct blood flow through heart
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Where do cutaneous nerves of the posterior cervical triangle emerge
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Near the middle of the posterior border of the SCM (nerve point of the neck)
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What are the cutaneous nerves of the posterior cervical triangle branches of
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They are branches of the cervical plexus of nerves which is formed by the anterior rami of spinal nerves C1-4
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What are the cutaneous nerves of the posterior cervical triangle
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Lesser occipital (C2)
Great auricular (C2-3) Transverse cervical (C2-3) Supraclavicular (C3-4) |
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Where do the supraclavicular nerves refer pain to
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The ipsilateral shoulder
carried superiorly in the phrenic nerve (C3-5) from the diaphragm |
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Where does the spinal accessory nerve descend
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Through the posterior triangle between the posterior border of the SCM and the anterior border of trapezius and supplies both muscles
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What happens when the spinal accessory nerve is injured
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Inability to shrug the shoulder and difficulty abducting the arm above the horizontal plane
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Other contents of the posterior cervical triangle
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Subclavian vein
Subclavian artery, third pt Suprascapular artery Roots, trunks, branches of the brachial plexus Branches of cervical plexus |
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What is the subclavian vein a continuation of
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The axillary vein at the lateral border of the first rib
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Where does the subclavian vein travelP
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Passes anterior to the anterior scalene muscle
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What does the subclavian vein join and then become
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Joins the internal jugular vein to form the braciocephalic vein
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What does the subclavian vein receive as a tributary
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External jugular vein
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What are the axillary and subclavian veins used for clinically
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To administer fluids and medications and to gain access to the R side of the heart
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Where is the 3rd part of the subclavian artery
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Extends between the lateral border of the anterior scalene muscle and the lateral border of the first rib
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What may be a branch of the 3rd pt of the subclavian artery
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The dorsal scapular artery may be a branch to levator scapulae and rhomboids
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How to control bleeding from UE
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Compress 3rd pt of subclavian artery against the first rib in the supraclavicular triangle
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What are the transverse cervical and suprascapular arteries branches of
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The thyrocervical trunk from the 1st part of the subclavian artery
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Where does the transverse cervical artery cross
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Cross the posterior cervical triangle toward the deep surface of the trapezius muscle
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Where does the suprascapular artery cross
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Crosses the posterior cervical triangle toward the superior border of the scapula
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Branching of the transverse cervical artery
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May divide into superficial and deep branches that course superficial and deep to the levator scapulae and rhomboids
If there is only a superficial branch, a dorsal scapular artery branches from the 3rd pt of the subclavian |
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Where are the roots of the brachial plexus
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Roots (Anterior rami) emerges with the subclavian artery into the interscalene triangle
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What is the interscalene triangle formed by
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Anterior and middle scalene muscles and 1st rib
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Thoracic outlet syndrome
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Stretching or compression of the inferior trunk of the brachial plexus or the subclavian artery due to cervical rib (enlarged costal process of C7) causing pain and paresthesia in neck and UE
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Phrenic nerve
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C3-C5
Motor innervation to diaphragm Descends along the anterior surface of the anterior scalene muscle |
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Suprascapular nerve
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C5-6
Accompanies the suprascapulaee artery and vein behind the clavicle en route to the supra and infraspinatus |
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Nerve to the subclavius triangle
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Nerve of the PCT
C5 May have accessory phrenic branch |
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Long thoracic nerve- what nerve levels, what does it innervate, and where is it?
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C5-7
Serratus anterior nerve of PCT |
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Dorsal scapular nerve - where is it and what does it pierce
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C5
To rhomoboids and levator scapulae Nerve of PCT Pierces middle scalene m. |
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Boundaries of anterior cervical triangle
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Anterior border of SCM
Midline of neck Inferior border of mandible Manubrium of sternum |
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Subdivisions of ACT
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submandibular/digastric triangle
submental triangle carotid triangle muscular triangle |
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Submandibular/digastric triangle
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Bounded by digastric muscle and mandible
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Submental triangle
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Above the hyoid bone between the anterior belly of the digastric muscle and the midline of the neck
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carotid triangle boundaries
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Bounded by the posterior digastric, superior belly of the omohyoid and the SCM
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Muscular triangle - boundaries
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defined by:
midline of neck superior belly of omohyoid SCM |
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Structures in superficial fascia over the anterior triangle of the neck
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Platysma muscles
Anterior jugular veins Transverse cervical nerves |
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Where do the anterior jugular veins descend
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Near the midline
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Where do the anterior jugular veins anastamose
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Paired veins, anastamose through a fascial suprasternal space, via jugular venous arch
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What does each anterior jugular vein drain into
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An external jugular vein
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What might the anterior jugular vein receive and what might it cause
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May receive large communicating vein from the facial vein along the anterior border of the SCM
Can cause bleeding after traumatic neck injury or during tracheostomy |
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Muscles in the anterior triangle
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Infrahyoid
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Superficial layer of infrahyoid mm
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2 parallel muscles:
Sternohyoid - medially Omohyoid sup. belly - laterally |
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What joins the superior and inferior bellies of the omohyoid
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Intermediate tendon
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Deep layer or infrahyoid muscles
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Formed by 2 muscles in series attaching to thyroid cartilage
Sternothyroid inferiorly Thyrohyoid superiorly |
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What do the infrahyoid muscles do
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Stabilize hyoid bone in position to provide base for tongue movements or depress hyoid bone
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What can the thyrohyoid muscle do
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Elevate the larynx
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What innervates the infrahyoid mm
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Ansa cervicalis
Formed by anterior rami of cervical spinal nerves 1-3 |
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Where is the thyroid gland
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Deep to the infrahyoid muscles
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What is the thyroid gland
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H shaped
Consists of: 2 lateral lobes Isthmus across tracheal rings 2-4 Frequently a pyramidal lobe extending superiorly from the isthmus |
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Blood supply of thyroid gland
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Superior thyroid arteries (external carotid)
Inferior thyroid arteries (thyrocervical trunk) 10% of time - thyroid ima a. |
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What veins drain the thyroid gland
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Superior, middle, and inferior thyroid veins
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What may a goiter compress
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Adjacent structures
Causes difficulty breathing (dyspnea) or swallowing (dysphagia) |
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What prevents upward expansion of goiter and what happens as consequence
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Sternothyroid muscles
May expand downwardly as retrosternal goiter and compress thoracic structures |
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Parathyroid glands
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2-8 of them
Usually in superior and inferior pairs on posterior surface of thyroid May be in aberrant positions Essential for life |
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Blood supply of parathyroid glands
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Usually from inferior thyroid arteries
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Carotid triangle - what is it and what are its boundaries
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Is a subdivision of the ACT
Boundaries: superior belly of omohyoid posterior belly of digastric anterior border of SCM |
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Contents of carotid triangle
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Cervical branch of CN VII
Common carotid artery and its division into the internal carotid and external carotid Branches of the external carotid artery Internal jugular vein Vagus nerve (CN X) Accessory nerve (XI) Hypoglossal nerve (XII) superior and inferior roots of the ansa cervicalis |
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Where does the R common carotid come from
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Brachiocephalic trunk
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L common carotid a
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Directly from the arch of the aorta
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How do the common carotids ascend the neck
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Within carotid sheaths
With internal jugular veins and vagus nerves |
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How to control bleeding from branches of carotid
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Compress against large anterior tubercle of Cv6 (carotid tubercle)
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Where do the common carotids divide
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Divide into internal and external carotid arteries near the upper border of the thyroid cartilage
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Specialized receptors of the common carotids
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At their bifurcation
Carotid sinus Carotid body |
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Carotid sinus
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Dilated proximal part of the internal carotid
Blood pressure receptor (CN IX) |
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Carotid body
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Flattened body deep to bifurcation
Chemoreceptor for blood gases (CN IX) |
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Carotid sinus syncope
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Hypersensitivity of carotid sinus to external pressure
Don't take carotid pulse at upper border of thyroid cartilage |
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Internal carotid arteries
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No branches in neck
Enter skull to become principal blood supply of cerebral hemispheres and structures within the orbit |
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TIAs or strokes
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loss of neurological function due to loss of cerebral blood flow
frequently due to plaques in internal carotids |
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carotid endarterectomy
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surgery to remove plaques
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Branches of external carotid arteries
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8 branches,
4-5 of which are in carotid triangle: |
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Branches of external carotid that are in carotid triangle
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Superior thyroid artery
Facial artery Lingual artery Ascending pharyngeal a. Occipital a. |
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Superior thyroid artery
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Usually the first branch of the external carotid
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Facial artery
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May arise from common stem with the lingual artery (instead of coming from the ext carotid)
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Ascending pharyngeal artery
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Arises from the medial side of the external carotid
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Occipital artery
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May or may not arise in carotid triangle
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3 branches of external carotid not in carotid triangle
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Posterior auricular
Superficial temporal Maxillary |
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Supercicial temporal artery
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One of the terminal branches of external carotid
Ascends in front of ear |
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Maxillary artery - where is it
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Other terminal branch of external carotid
Passes to the infratemporal fossa deep to the ramus of the mandible |
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What is the internal jugular vein a continuation of
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Continuation of the sigmoid sinus, a dural venous sinus
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What is the largest vein in the head/neck
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Internal jugular
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Where is the internal jugular vein
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Within the carotid sheath, lateral to the carotid artery
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What are the dilatations of the internal jugular vein
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Superio and inferior bulbs, at superior and inferior ends
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Where is the inferior bulb of the internal jugular vein
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Just above the union of the internal jugular vein with the subclavian vein to form the braciocephalic vein
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What causes distention of the internal jugular vein
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Obstruction of venous return to the RA, e.g.
Tension pneumothorax Cardiac tamponade SVC syndrome |
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Deep cervical lymph nodes - where are they, what do they drain, and what divisions are there
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Along internal jugular vein
drain all lymph from the head and neck 2 major groups: Upper/superior deep cervical nodes lower/inferior deep cervical nodes |
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What is the clinical use of internal jugular veins
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May be used for insertion of central venous catheter into heart
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Where is the vagus nerve
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Descends within the carotid sheaths behind and between the carotid arteries and internal jugular veins
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What does the vagus nerve supply
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Sensory to larynx and lower part of pharynx
Innervates muscles of larynx, pharynx, soft palate Thoracic and abdominal organs |
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Other nerves in ACT
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ansa cervicalis
hypoglossal nerve |
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Ansa cervicalis
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Nerve loop that innervates the infrahyoid mm
In ACT |
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hypoglossal nerve - what does it do and where is it?
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CN XII
innervates muscles of tongue in ACT |
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Where is the suprahyoid region and what does it contain
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Located b/w hyoid bone and inferior border of mandible
Contains submandibular and submental triangles |
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Boundaries of submandibular triangle
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Inferior border of mandible
Anterior ( CN V) and posterior (CNVII) bellies of the digastric muscle |
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What do the anterior and posterior bellies of the digastric muscle do
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Elevate the hyoid bone or depress the mandible (open jaws)
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Stylohyoid muscle - where is it, what innervates it, and what does it do
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in submandibular triangle
Runs parallel to the posterior belly of the digastric Innervated by CN VII Draws the hyoid bone upward and backward |
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Floor of submandibular triangle
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2 mylohyoid muscles (CNV) that fuse in midline fibers to form floor of oral cavity
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Mylohyoid muscles - what innervates, what do they form, what do they do
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CN V
fuse in midline raphe to form floor of oral cavity elevate the hyoid bone and tongue or depress mandible |
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Submandibular salivary
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In submandibular triangle
Innervated by postganglionic parasymp fibers from cell bodies in submandibular ganglion |
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Cervical plexus of nerves
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Formed by anterior rami of spinal nerves C1-4
Has cutaneous branches |
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What does the cervical plexus form
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Ansa cervicalis
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What are the roots of the ansa cervicalis
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Superior root from C1
Inferior root from C2-3 Nerve to thyrohyoid and geniohyoid appear to branch from CN XII but they just travel together |
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Where does the ansa cervicalis form its nerve loop
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Anywhere between the angle of the mandible and the clavicle
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What gives rise to msot of the phrenic nerve
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The cervical plexus of nerves
It is formed from the anterior rami of C3-5 |
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What does the cervical plexus provide proprioception for
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Proprioceptive nerve fibers to
SCM (C2) and trapezius (C3,4) |
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What is the root of the neck
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The junctional area between the thorax and neck
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What is the inferior boundary of the root of the neck
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the superior thoracic aperture
Body of the first thoracic vert First pair of ribs and their costal cartilages Manubrium of sternum |
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Divisions of subclavian artery in the root of the ncek - where are its divisions
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Divided into 3 parts relative to the the anterior scalene muscle
1st part is medial to the anterior scalene 2nd part is posterior to it 3rd part is lateral to it |
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Where is the 1st part of the subclavian artery
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Rests against the cervical pleura
Causes contact impression on lung |
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branches of the 1st part of the subclavian
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vertebral artery
internal thoracic artery thyrocervical trunk |
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where is the vertebral artery
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ascends to the transverse foramen of Cv6
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Where is the internal thoracic artery
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descending into the mediastinum
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what are the branches of the thyrocervical trunk
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transverse cervical
suprascapular inferior thyroid (branches into ascending cervical) |
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Branches of the 2nd part of the subclavian artery
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costocervical trunk
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divisions of the costocervical trunk
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Deep cervical artery
Supreme/superior intercostal artery |
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What forms the anastamosis between the carotid and subclavian arterial systems
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Anastamoses between deep cervical artery and the descending branch of the occipital artery
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What may replace the deep branch of the tranverse cervical artery
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the dorsal scapular artery if it is a branch from the 3rd part of the subclavian
to levator scapulae and rhomboids |
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What may be injured above the first rib in the root of the neck
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apex of lung and cervical pleura (cupola) if there is a penetrating wound
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pancoast tumor
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tumor of the apex of the lung
may spread to neck structures, e.g. lower roots of brachial plexus, cervical symp trunk, phrenic nerve, recurrent laryngeal nerve |
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What are vulnerable during a subclavian venous puncture
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pleura and lung because the subclavian artery and vein arch across the cervical pleura and apex of the lung
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Anterior to anterior scalene muscle
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phrenic nerve
transverse cervical artery suprascapular artery subclavian vein ascending cervical artery |
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posterior to anterior scalene muscle
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subclavian artery
roots of the brachial plexus |
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what presents hazards during tracheotomy
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midline structures:
anterior jugular vein large communicating vein from facial vein jugular venous arch isthmus of thyroid gland inferior thyroid veins thyroid ima artery L brachiocephalic vein or thymus (in children) |
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Recurrent laryngeal nerve
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in the tracheoesophageal groove on each side
supply all but 1 pair of intrinsic mm of larynx in danger during thyroid surgery and by goiters |
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What does the R recurrent laryngeal nerve curve around
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R subclavian artery
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thoracic duct
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passes behind the structures in the L carotid sheath
loops anteriorly and inferiorly to end in or near the jxn of the L internal jugular and subclavian veins (L venous angle) |
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R lymphatic duct - where is it, what forms it, and what does it drain
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On R side of root of neck
formed by union of: R jugular subclavian brochomediastina lymp trunks Drains into R venous angle |
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What innervates the facial expression muscles
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Facial nerve (CN VII)
B/c they develop from 2nd pharyngeal arch |
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Orbicularis oculi
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3 portions -
Palpebral portion is in eyelids and closes them gently (blinking) Orbital portion surrounds orbit to close eyelids forcefully Lacrimal portion is deep and medial and aids in draining tears |
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Muscles of eye
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?
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Paralysis of orbicularis oculi
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From damage to CN VII
Inability to fully close eyelids, drying and ulceration of cornea |
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Corrugator supercilii
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Draws eyebrows downward and medialward for wrinkling of forehead
Paralyzed with botox |
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Muscles for nose?
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?
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Nasalis action
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Transverse part compresses nostrils
Alar part dilates (flares) nostrils |
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Depressor septi nasi
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Asssists alar part of nasalis in flaring nostrils
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Procerus
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Draws medial part of eyebrows downward to produce transverse wrinkles over bridge of nose (frowning)
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Orbicularis oris
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Encircles lips
Both intrinsic and extrinsic muscle fibers Can purse lips, flatten them against teeth or close them |
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Muscles of mouth - upper group
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Risorius
Zygomaticus major and minor Levator labii superioris alaeque nasi Levator labii superioris Levator anguli oris |
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Risorius
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Pulls corners of mouth laterally and upward (grin)
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Zygomaticus major and minor
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Raises corner of mouth and moves it laterally (smile)
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Levator labii superioris alaeque nasi
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Elevates upper lip and helps dilate nostril (snarl)
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Levator labii superioris
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Deepens furrow between nose and corner of mouth (sadness, smile)
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Levator anguli oris
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Elevates corner of mouth and helps and helps deepen furrow between nose and mouth (sadness, smile)
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Lower group of mouth muscles
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Depressor anguli oris
Depressor labii inferioris Mentalis |
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Depressor anguli oris
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Depresses corners of mouth (e.g. frowning)
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Depressor labii inferioris
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Depresses lower lip and moves it laterally
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Mentalis
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Pouting muscle
Raises and protrudes lower lip used to drink from cup |
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Buccinator
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Bugler's muscle
Holds food between teeth during chewing If it is paralyzed the buccal mucosa slips between the teeth during chewing and is lacerated Assists in forceful expulsion of air from cheeks |
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Where does the upper lip go
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Extends from nose to opening of mouth and laterally to nasalbial grooves
Grooved by philtrum |
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Where does the lower lip go
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Extends inferiorly to the labiomental groove
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Occipitofrontalis muscle
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Frontal belly elevates eyebrows and wrinkles skin of forehead (surprise, curiosity) and protracts scalp
Occipital belly retracts scalp and helps frontal belly |
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Platysma (facial expression)
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Moves lower lip and corners of mouth down
Tenses skin of inferior face and neck |
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Auricular muscles
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Anterior - pulls ear upward and forward
Posterior - retracts and elevates ear Superior - elevates ear |
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Muscles for smiling
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Zygomaticus major and minor
Orbicularis oculi Levator labii superioris Levator anguli oris Risorius |
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Muscles for frowning
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Orbicularis oculi
Platysma Corrugator supercilii Orbicularis oris Mentatlis Depressor anguli oris |
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Branches of the facial nerve
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Nerve to stylohyoid and posterior digastric
Posterior auricular nerve Parotid plexus |
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What are the consequences of delegation? (2)
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[1] Delegating party remains liable.
[2] Delegate liable to oblige only if he receives consideration from delegating party. |
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Parotid plexus - branches
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The Zoo Borrowed My Crocodile
Upper/temporofacial trunk: Temporal Zygomatic Buccal Lower/cervicofacial trunk: Buccal Marginal mandibular Cervical |
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Temporal branch of facial nerve - what does it supply
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Muscles in area of temple, forehead, and supra orbital
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Zygomatic branch of facial nerve
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Innervates muscles in infraorbital area, lateral nasal area and upper lip
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Buccal branch of facial nerve
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Innervates muscles of cheek, upper lip and corner of mouth
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Marginal mandibular branch of facial nerve
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Innervates muscles of lower lip and chin
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Cervical branch of facial nerve
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Innervates platysma
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Facial nerve palsy
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Lesion of facial nerve - paralysis of ipsilateral muscles of facial expression
Causes: Birth injury Parotid gland surgery Injury to temporal bone Viral inflammation of nerve Brainstem injury Bell's palsy (idiopathic) |
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Major divisions of CN V
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Opthalmic (V1) near the eye - sensory
Maxillary (V2) to upper jaw - sensory Mandibular (V3) to lower jaw - mixed sensory and motor |
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Cutaneous nerves of the face from V1
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Supraorbital
Infratrochlear Lacrimal External nasal |
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Cutaneous nerves of face from V2
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Infraorbital
Zygomaticofacial Zygomaticotemporal |
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Cutaneous branches of face from V3
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Mental nerve
Buccal nerve Auriculotemporal nerve |
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Blood supply of the face
|
Branches of external carotid:
Facial and branches Superficial temporal br. Branches of axillary Internal carotid: Branches of opthalmic |
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Branches of facial artery to face
|
Angular artery (most superior)
Inferior labial a. Superior labial a. Lateral nasal a. |
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Branches of supercicial temporal a. to face
|
Transverse facial artery
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Branches of maxillary a. to face
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Infraorbital a.
Buccal a. Mental a. |
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Branches of opthalmic a. to face
|
Zygomaticofacial a.
Zygomaticotemporal (br. of lacrimal) Dorsal nasal a |
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What does the facial vein begin as
|
The angular vein
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What forms the common facial vein
|
Anterior branch of retromandibular vein and facial vein
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Spread of infection to cavernous sinus
|
Connections between facial vein and other veins in danger zone of face
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Cavernous sinus thrombosis
|
Due to thrombophlebitis of facial vein secondary to infection
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Lymph nodes of the face
|
Submental
Submandibular Preauricular and parotid |
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Where is the parotid gland
|
Partially in a space formed by bony structures
Part of gland is between ramus of mandible and mastoid process of temporal bone |
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Parotiditis
|
Pain during chewing due to mastoid process of temporal bone
In mumps |
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What encloses parotid gland
|
Parotid sheath
Contributes to pain during inflammation because resists stretching |
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What are the parts of the parotid gland
|
superficial and deep parts
Connected by isthmus |
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What does the parotid gland do
|
Secretes into the oral cavity via the parotid duct
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Secretomotor innervation of parotid gland
|
Preganglionic parasympathetic fibers from CN IX - travel in tympanic nerve, tympanic plexus and lesser petrosal nerve
Postganglionic parasympathetic fibers from cell bodies in otic ganglion (infratemporal fossa) - travel with auriculotemporal (CN V3) to reach gland |
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Sensory innervation of parotid gland
|
auriculotemporal nerve (Cn V3)
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Structures that may be injured by parotid tumor or surgery
|
Facial nerve and its branches
Retromandibular vein and its tributaries, superficial temporal and maxillary veins External carotid a. and its terminal branches; the supeficial temporal, posterior auricular and maxillary aa Auriculotemporal n (V3) |
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Layers of scalp
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Skin
dense CT Aponeurosis Loose CT pericranium |
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Dense CT of scalp
|
Hold abundant blood vessels open
If lacerated, tends to bleed profusely |
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Aponeurosis of scalp - what does it connect
|
AKA epicranial
Connects frontal and occipital bellies of occipitofrontalis muscle Causes gaping of wounds if lacerated in a coronal plane due to muscle pull |
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Cutaneous innervation of anterior part of scalp
|
Branches of trigeminal n:
Supratrochlear and supraorbital (CN V1) Zygomaticotemporal (CN V2) Auriculotemporal (CN V3) |
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Cutaneous innervation of posterior part of scalp
|
Branches of cervical spinal nerves 2 and 3:
Posterior rami - greater occipital (C2) and 3rd occipital (C3) Anterior rami - great auricular (C2-3) and lesser occipital (C2-3) |
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Innervation of occipitofrontalis and auricular
|
Muscles under scalp
Facial nerve |
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Temporalis muscle - where is it and what innervates it?
|
Under scalp
Deep temporal nn (brs of CN V3) |
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Blood supply of scalp
|
Branches of opthalmic artery - anteriorly
Branches of external carotid posteriorly Anastamoses |
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Veins of sclap
|
Accompany arteries
Drain scalp and calvarial diploic veins |
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Anterior blood supply of scalp
|
Branches of opthalmic:
Supratrochlear Supraorbital |
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Posterior blood supply of scalp
|
Branches of external carotid:
Superficial temporal Posterior auricular Occipital |
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|
Whaat is the danger area of the scalp
|
Loose CT layer
Because infection spreads easily within it and can spread from it through emissary veins to intracranial structures, causing dural venous sinus thrombosis or meningitis |
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Why can black eyes result from scalp or forehead injury
|
Because the loose CT layer allows blood to spread anteriorly into the eyelids and the root of the nose
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Where does the scalp detach in a scalping injury
|
the loose CT layer
with 3 more superficial layers detaching as unit |
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Lymph nodes of the scalp
|
Occipital nodes
Upper deep cervical nodes mastoid nodes Pre-auricular and parotid nodes |
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Viscerocranium - what bones does it include
|
Facial skeleton:
Nasal Palatine Lacrimal Zygomatic Maxilla Inferior conchae Unpaired vomer and ethnoid |
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Neurocranium - what bones does it include
|
Cranial vault with calvaria
Cranial base Temporal and parietal Frontal Occipital Sphenoid Ethmoid |
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Skull
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Mandible
Cranium |
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Cranial base
|
Cranial floor:
Anterior cranial fossa Middle cranial fossa Posterior cranial fossa |
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|
How are cranial nerves numbered
|
In rostral-caudal sequence that they pierce the dura mater of the cranial base
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|
A gratuitous assignment ceases to be revocable to the extent that before the assignee’s right is terminated: (4)
|
[1] the obligor has already performed (i.e., there has been payment or satisfaction of the obligation); or
[2] the assignee has obtained a judgment against the obligor, or [3] the assignee has entered into a new K w/ the obligor by Novation; or [4] the assignee has relied on the assignment in a way that is reasonable, foreseeable, and detrimental. |
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Sutures of skull
|
Fibrous joints
Allow growth between adjacent bones of infant's skull Most calvarial sutures begin to fuse in 3rd decade |
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What may happen with premature fusion of a suture
|
AKA Craniosynostosis
Distortion of head shape |
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Fontanelles -- what do they become when they close
|
Sites where sutures intersect
Anterior fontanelle - baby's soft spot (used to assess ossification, intracranial pressure and level of hydration); becomes bregma when closes Posterior fontanelle - becomes lambda when closes |
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Bones of the cranial vault
|
External table of compact bone
Internal table of compact bone (thinner) Central layer of cancellous bone where the diploic veins are part of the route for intracranial spread of infection |
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|
Hydrocephalus
|
Dilatation of cerebral ventricular system due to:
Obstruction of CSF flow CSF overproduction Failure of CSF reabsorption |
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|
Dural folds
|
Cerebral falx (falx cerebri)
Tentorium cerebelli with oval opening - tentorial notch Falx cerebelli Diaphragma sellae |
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|
What do the dural folds subdivide
|
Partly subdivide cranial cavity into supratentorial and infratentorial compartments that communicate via tentorial notch
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|
Uncal herniation
|
Through the temporal lobe
Goes through tentorial notch and pressures brainstem Produces ipsilateral pupillary dilation and contralateral paralysis of body |
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|
Cingulate herniation
|
Most common
Frontal lobe is squeezed under falx cerebri Interference with blood vessels increases intracranial pressure |
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Arterial supply of anterior fossa of dura mater and neurocranium
|
Anterior meningeal aa (branches of ethmoidal aa > opthalmic a)
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Arterial supply of middle fossa of dura mater and neurocranium
|
Middle and accessory meningeal aa (branches of maxillary)
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ARterial supply of posterior fossa of dura mater and neurocranium
|
Posterior meningeal a (br of ascending pharyngeal a)
Meningeal brs of ascending pharyngeal, occipital and vertebral aa |
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|
ARterial supply of brain
|
Vertebral a:
Basilar a > posterior cerebral a, cerebellar aa and pontine aa Internal carotid aa: Anterior cerebral a Middle cerebral a Opthalmic a |
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Opthalmic a?
|
?
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|
Middle meningeal artery
|
Traverses pterion (temporal region of skull) and a fracture there may cause extradural (epidural) hematoma
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|
Dural venous sinuses - where are they. what do they drain and what is included
|
Between periosteal and meningeal layers of dura mater or in folds
Drain most of blood from brain Include: Superior sagittal sinus Inferior sagittal sinus Straight sinus Transverse sinus Occipital sinus Cavernous and intercavernous Sphenoparietal sinuses Inferior & Superior petrosal Basilar plexus |
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|
Which sinuses meet at confluence of sinuses
|
Occipital, strait and sagitall sinuses
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|
Basilar plexus - what is it continuous with and what is its clinical signifiance
|
Continous with internal vertebral plexus - spread of cancer cells or infection from vertebral canal into cranial cavity
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|
What does the sigmoid sinus become
|
Internal jugular vein as it exits cranial cavity
Drains most of venous blood from cranial cavity |
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|
Cavernous sinus - where is it and what is its clinical sig
|
Lateral to sella turcica
Important connections to other dural sinuses Connections to opthalmic veins (spread of infection from midface) |
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|
What traverse the cavernous sinus and what is the clinical relevance
|
Internal carotid artery and abducent n (VI)
Tear in artery (cranial base fracture) produces arteriovenous fistula and pulsating exophthalmos |
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|
Innervation of dura mater
|
Branches of ethmoidal nerves (V1) in anterior cranial fossa
Meningeal branch of V1 to falx cerebri and tentorium cerebelli Meningeal branches of V2 and V3 in middle cranial fossa Meningeal branches of spinal nerves C1-3 in posterior cranial fossa |
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|
What are the sources of mesenchyme in the head
|
Paraxial mesoderm --> somitomeres and somites
Lateral plate mesoderm Neural crest ectomesenchyme ectodermal placodes (thickenings of ectoderm) |
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|
What is the role of neural crest cells in forming skeletal tissues in the head
|
Neural crest cells migrate into pharyngeal (branchial) arches to surround cores of mesoderm
Form pharyngeal arch and facial skeletal and other CTs |
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|
What are the contributions of paraxial mesoderm to the head
|
Forms:
Posterior portions of cranial base and cranial vault Skeletal muscles of craniofacial region Dermis, other CT and caudal meninges |
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|
What does lateral mesoderm form
|
Laryngeal cartilages
Other CTs |
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|
What is formed when neural crest cells join with ectodermal placodes
|
Sensory ganglia of CN V, VII, IX, and X
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|
When do pharyngeal arches first appear
|
DUring 4th and 5th weeks of development
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|
How do pharyngeal arches develop
|
As bars of mesenchyme separated externally by pharyngeal clefts and internally by pharyngeal pouches
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|
What does each pharyngeal arch have
|
Skeletal component
Muscular components Nervous component Arterial component |
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|
What is another name for the 1st pharyngeal arch
|
Mandibular arch
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|
What does the 1st arch consist of (processes)
|
A maxillary process on each side
Mandibular process in region of future jaw |
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|
What does the 1st arch join to become
|
Joins the frontonasal prominence to form face around stomodeum (primitive oral cavity)
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|
What is the 1st arch cartilage
|
Meckels cartilage - around which the mandible forms intramembranously
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|
What does the 1st arch cartilage form
|
Malleus
Incus Ant lig of middle ear Sphenomandibular ligament |
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|
Parts of the skull that develop from 1st arch through intramembranous ossification
|
maxilla
premaxilla zygomatic bone squamous part of temporal bone |
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|
What muscles does the 1st arch give rise to
|
Muscles of mastication:
masseter temporalis lateral pterygoid medial pterygoid mylohyoid ant belly of digastric tensor veli palatini tensor tympani |
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|
What is the nerve of the 1st arch
|
Trigeminal nerve (CN V)
Innervates muscles through its mandibular division (V3) Provides sensory innervation to face through: Ophthalmic (V1) Maxillary (V2) Mandibular (v3) divisions |
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|
What is another name for the 2nd arch
|
Hyoid arch
|
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|
What is the cartilage of the 2nd arch
|
Reichert's cartilage
|
|
|
What does the 2nd arch cartilage give rise to
|
Stapes
styloid process of temporal bone stylohyoid ligament lesser horn upper pt of body of hyoid |
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|
What muscles come from 2nd arch
|
Muscles of facial expression
Sylohyoid Post belly of digastric stapedius |
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|
what is the nerve of the 2nd arch
|
Facial nerve (CN VII)
Innervates muscles from 2nd arch Sends chorda tympani branch to 1st arch to carry taste from ant 2/3 of tongue |
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|
What does cartilage from the 3rd arch form
|
Lower part of body and greater horn of hyoid bone
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|
|
What does the 3rd arch give rise to
|
Stylopharyngeus muscle
Innervated by nerve of 3rd arch - glossopharyngeal nerve (CN IX) |
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|
What are the cartilages of the 4th and 6th arches
|
Cartilaginous components that fuse to form cartilages of the larynx -
thyroid cricoid arytenoid corniculate cuneiform |
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|
What muscles come from the 4th arch
|
Muscles of soft palate except tensor veli palatini
Muscles of pharynx except stylopharyngeus cricothyroid muscle of larynx |
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|
what is the nerve of the 4th arch
|
pharyngeal branch of vagus (CN X) to muscles of soft palate and pharynx
external laryngeal branch of vagus to cricothyroid |
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|
What muscles arise from 6th arch
|
intrinsic muscle of larynx except cricothyroid
innervated by recurrent laryngeal br of vagus n |
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|
What are pharyngeal pouches
|
outpocketings of pharyngeal wall separating arches internally
5 pairs, although 5th pair is atypical and is considered part of the 4th Epithelial lining of pouches contributes to number of important organs |
|
|
What is the 1st pouch called
|
tubotympanic recess
|
|
|
What does the 1st pouch come into contact with
|
epithelium of 1st pharyngeal cleft (external auditory meatus)
|
|
|
What does the 1st pouch form
|
Primitive tympanic (middle ear) cavity
Auditory (eustachian tube) Contributes to tympanic membrane (eardrum) |
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|
What does the 2nd pouch form
|
Helps form palatine tonsil
Partially persists in adult as tonsillar fossa |
|
|
What does the 3rd pouch form
|
Dorsal portion forms inferior paraT gland
ventral portion forms thymus |
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|
What does the 4th pouch form
|
Dorsal portion forms superior PT gland
ventral portion (really 5th pouch) forms ultimobranchial body |
|
|
What does ultimobranchial body do
|
Migrates caudally with thyroid
Gives rise to parafollicular (C) cells of thyroid that secrete calcitonin |
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|
Which PT glands are particulary variable in position
|
Inferior PT glands
|
|
|
4 pairs of clefts of 5 wk old embryo form what
|
External auditory meatus
Temporarily form cervical sinus when 2nd arch overgrows 3rd and 4th to fuse with epicardial ridge |
|
|
External auditory meatus
|
Develops from 1st cleft
plugged from 3rd-7th months by meatal plug that degenerates Contributes ectodermal cells that join lining of 1st pouch to form tympanic membrane |
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|
What may cause deafness
|
Persistence of meatal plug
|
|
|
Auricle - what does it develop from
What is the clinical significance |
Develops from auricular hillocks each of 1st and 2nd arches
INvolved in external ear defects that often occur as part of chromosomal syndromes |
|
|
What is a lateral cervical cyst
|
Branchial cyst
Remnant of cervical sinus located laterally along anterior border of SCM May be fistula connecting it with surface |
|
|
Face development
|
From 5 facial primordia:
Frontonasal prominence 2 maxillary prominences 2 mandibular prominences Beginning in fourth week |
|
|
What forms the nasal pit
|
medial and lateral nasal prominences that develop on sides of nasal placode
|
|
|
What do the 2 medial nasal prominences form
|
Intermaxillary segment
|
|
|
What does the intermaxillary segment form
|
Philtrum of upper lip
Portion of maxillary alveolar process carrying 4 incisor teeth Primary palate |
|
|
What is the premaxilla
|
Primary palate and maxillary alveolar process carrying incisor teeth
|
|
|
What forms the upper lip
|
fusion of the medial nasal and maxillary prominences
|
|
|
What is the nasolacrimal groove
|
Separation between lateral nasal and maxillary prominences
Later the nasolacrimal duct forms there to connect the lacrimal sac in the orbit and the inferior meatus of nasal cavity |
|
|
What forms the dorsum of the nose
|
frontonasal prominence
|
|
|
What forms the sides of the nose
|
lateral nasal prominences
|
|
|
What forms the crest and tip of the nose
|
Merged medial nasal prominences
|
|
|
What initially separates nasal pit from oral cavity
|
oronasal membrane
|
|
|
What does the oronasal membrane form
|
breaks down at future site of incisive canals to form primitive choanae
|
|
|
What forms the lower lip
|
Mandibular prominences
|
|
|
What forms the secondary palate
|
Lateral palatal shelves - outgrowths from maxillary prominences that are vertically oriented on each side of tongue
|
|
|
What happens to the palatal shelves
|
Fuse in midline with each other
Fuse above with nasal septum Fuse ant with primary palate |
|
|
What is the midline landmark on skull between primary and secondary palates
|
Incisive fossa, containing incisive canals
|
|
|
What causes facial clefts
|
Failure of fusion of facial processes
|
|
|
What can happen as a result of deficient neural crest migration and proliferation
|
Abnormally small facial processes and clefts
|
|
|
Cleft lip
|
Failure of maxillary and medial nasal prominences to fuse
|
|
|
What does the anterior 2/3 (body) of tongue mucosa develop from
|
1st arches when lateral lingual swellings overgrow tuberculum impar
|
|
|
What does the posterior 1/3 (root) of tongue mucosa develop from
|
When tissue from 3rd arches overgrows that of 2nd arches in copula (hypobranchial eminence)
|
|
|
Extreme posterior part of tongue mucosa
|
From epiglottic swelling of 4th arch
|
|
|
GSA tongue mucosa anterior 2/3
|
from nerve of 1st arch
CN V |
|
|
SVA (taste) to ant 2/3 of tongue mucosa
|
chorda tympani br of n of 2nd arch (CN VII) joins lingual br of mandibular n (V3)
|
|
|
GVA and SVA in posterior 1/3 of tongue
|
n of 3rd arch - CN IX
|
|
|
sensation and taste to extreme posterior part of tongue
|
superior laryngeal br of vagus n
|
|
|
what do tongue muscles develop from
|
myoblasts that migrate from occipital somites
carry nerve supply from CN XII with them |
|
|
Ankyloglossia
|
Tongue tie
insufficient tissue degeneration too short lingual frenulum |
|
|
bifid tongue
|
incomplete fusion of lateral lingual swellings
|
|
|
What does the thyroid gland begin as
|
Endodermal proliferation between tuberculum impar and copula, later marked by foramen cecum
|
|
|
What connects the thyroid primordium to foramen cecum
|
thyroglossal duct
|
|
|
Where might a thyroglossal cyst or aberrant thyroid tissue be found
|
anywhere along path of migration
|
|
|
thyroglossal cyst or aberrant thyroid tissue
|
in or near midline
subject to same diseases as thyroid |
|
|
Pyramidal lobe
|
superioly from isthmus of thyroid along path of migration
attached to hyoid bone by CT and/or levator glandulae thyroideae |
|
|
What does the skull develop from
|
Paraxial mesoderm and neural crest cells
|
|
|
What is the viscerocranium
|
Facial skeleton
|
|
|
What is the neurocranium
|
encloses, supports, protect brain
|
|
|
What is involved in development of neurocranium
|
Endochondral ossification in cranial base - chondrocranium
Intramembranous ossification in cranial vault - desmocranium |
|
|
What does the chondrocranium develop from
|
Anterior to hypophyseal fossa from neural crest cells
Posterior to hypophyseal fossa from paraxial mesoderm From series of cartilages with the: Parachordal cartilage and occipital sclerotomes forming the basiooccipital bone Hypophyseal cartilages fusing to form body of sphenoid trabeculae cranii fusing to form ethmoid bone Ala orbitalis --> lesser wing of sphenoid bone ala temporalis --> greater wing of sphenoid periotic capsule --> petrous and mastoid parts of temporal bone |
|
|
Where does growth of cranial base occur
|
Synchondroses (cart joints)
Sutures (firbous) |
|
|
Where does growth of cranial vault occur
|
Sutures
fontanelles |
|
|
Where is the only place bone can grow
|
On surfaces -- appositional growth
|
|
|
craniosynostosis
|
premature fusion of sutures
growth is restricted perpendicular to fused sutures and overgrowth occurs other places |
|
|
scaphocephaly
|
Long narrow skull with frontal and occipital bossing and often median ridge
From early fusion of sagittal suture |
|
|
trigonocephaly
|
wedge shaped deformity of forehead due to premature fusion of metopic suture
|
|
|
oxycephaly
|
tower skull
abnormally tall with decrease in anteriorposterior length From B/L coronal suture fusion with other involvement |
|
|
plagiocephaly
|
neurocranial and facial assymetry
due to unilateral premature fusion of coronal and/or lamboidal structures frontal(anterior) or occipital (posterior) |
|
|
frontal plagiocephaly
|
U/L flattening of forehead due to premature fusion of ipsilateral coronal suture and often sphenofrontal suture
Contralateral forehead and parietal bone bulge |
|
|
occipital plagioephaly
|
U/L flattening of occipit due to ipsilateral fusion of lamboid suture
contralateral side of occipit bulges dinstinguished from deformational plagiocephaly due to supine sleep position |
|
|
Faciostenosis
|
hypoplasia of middle 1/3 of facial skeleton
difficulty breathing, speaking, eating |
|
|
Other anamolies present in craniosynostoses
|
Faciostenosis
Exopthalmos Orbital hyper/hypo telorism Increased IC pressure hydrocephalus |
|
|
What causes the exopthalmos during faciostenosis
|
Decrease in volume of the orbit (orbitostenosis)
|
|
|
what is hyper/hypo telorism
|
Abnormally wide and narrow separation between eyes
|
|
|
What's another cause of craniosynostosis
|
Mechanical factors - growth constraint
Mutations in FGFR1 and 2 |
|
|
Where does CN V arise
|
From the pons of the midbrain as 2 roots:
A large sensory root Small motor root |
|
|
Where is CN V's sensory ganglion
|
Large sensory ganglion (trigeminal ganglion or semilunar) on the floor of the middle cranial fossa
|
|
|
What constitutes the 3 divisions of the nerve
|
Peripheral processes of the neurons of trigeminal ganglion
|
|
|
What are the divisions of CN V and where do they exit
|
Exit middle cranial fossa through separate foramina
V1-opthalmic --> superior orbital fissure V2 maxillary --> foramen rotundum V3 mandibular --> foramen ovale |
|
|
What 2 functional components does CN V have at its origin
|
GSA - through 3 divisions, provide general sensation to skin on the anterior head, the nasal cavity, paranasal sinuses, most of the oral cavity (incl all teeth), ant 2/3 of tongue, TMJ, dura mater
SVE - carried by mandibular division provides motor supply to muscles derived from pharyngeal arches: mm of mastication, ant belly of digastric m, mylohyoid, tensor veli palatini, tensor tympani |
|
|
Cutaneous innervation by CN V and its divisions
|
CN V - face, anterior scalp, temporal region
v1- opthalmic division supplies forehead and anterior scalp v2- maxillary division supplies middle face v3- mandibular division innervates area of mandible and temple |
|
|
Divisions of V1
|
Frontal n
Nasociliary n lacrimal n |
|
|
Frontal n - divisions and innervation
|
Divides into:
Supraorbital n Supratrochlear n Supplies: Forehead Scalp Frontal sinus Upper eyelid |
|
|
What fibers does the ophthalmic nerve have at its origin
|
GSA
|
|
|
Nasociliary n. - divisions and innervation
|
Supplies:
Iris Cornea Nasal sinuses Terminal superficial brs: External nasal n. Infratrochlear nn |
|
|
Lacrimal n - innervation
|
Sensory to conjunctiva and skin of upper eyelid
|
|
|
What fibers does the maxillary nerve contain at its origin
|
GSA
|
|
|
What are the branches of the maxillary nerve
|
Supplies middle face through 3 cut. brs.:
Infraorbital zygomaticofacial n zygomaticotemporal n |
|
|
Path of maxillary n
|
Maxillary n enters pterygopalatine fossa and gives off zygomatic n and continues as infraorbital nn
zygomatic n gives rise to zygomaticofacial and zygomaticotemporal nn |
|
|
What does the infraorbital n supply
|
Palate
Maxillary sinus Posterior teeth Then traverses infra-orbital foramen |
|
|
Branches of mandibular division
|
Supplies the mandibular and temporal area through 3 cut. nn
Auriculotemporal n to temple Buccal n to cheek Mental n to chin |
|
|
Other cut. innervation to head
|
Via cervical plexus, specifically:
Transverse cervical Great auricular Lesser occipital Over mandible and posterior auricular region |
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What innervates cut. occipital region and posterior scalp
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Posterior rami
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What do SVE innervate
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Skeletal mm that develop from arches
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What innervates the 1st arch with SVE and what muscles does it include
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CN V3
mm of mastication mylohyoid ant belly of digastric tensor veli palatini tensor tympani |
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What innervates arch 2 with SVE and what mm are in it
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CN VII
mm of facial expression stapedius stylohyoid post belly of digastric |
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What innervates arch 3 with SVE and what mm are in t
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stylopharyngeus
CN IX |
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What innervates arch 4/5 with SVE and what mm are in it
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mm of pharynx (Except stylopharyngeus)
intrinsic mm of larynx mm of palate (exc tensor veli palatini) striated mm of esophagus |
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What are the mm of mastication and other mm from arches and what are the branches of V3 that supply them
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Temporalis (deep temporal nn)
Lateral pterygoid (n to lateral pterygoid) Masseter (masseteric n) medial pterygoid (n to medial pterygoid) tensor veli palatini (n to medial pterygoid) tensor tympani (n to medial pterygoid) mylohyoid (n to mylohyoid) ant belly of digastric (n to mylohyoid) |
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Deep temporal nn
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Supplies temporalis
From V3 |
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N to lateral pterygoid
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Supplies:
Lateral pterygoid From V3 |
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Masseteric n
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Supplies masseter m
From V3 |
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N to medial pterygoid
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Supplies:
medial pterygoid tensor veli palatini tensor tympani From V3 |
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N to mylohyoid
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Supplies:
N to mylohyoid Ant belly of digastric From V3 |
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Where does V3 go
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Exits the cranial cavity through the foramen ovale
Gives rise to: Meningeal br (sensory) N to medial pterygoid (motor) Divides into: anterior and posterior division |
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Anterior division of V3
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Mostly motor to mm of mastication
Buccal nerve Masseteric n (motor) Deep temporal nn (motor) N to lateral pterygoid (motor) |
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Buccal n
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From ant division of V3
Sensory only to buccinator m |
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Posterior division of V3
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Mostly sensory
Auriculotemporal n (sensory) Lingual n (sensory) Inf alveolar n |
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Branches of inf alveolar n
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N to mylohyoid (motor)
Mental n (Sensory) |
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Auriculotemporal n
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Branches from post division of mandibular n
Splits around middle meningeal a Carries postgan parasym fibers from otic ganglion to parotid gland Distributes to temporal region and auricle |
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Lingual n what is it a branch of, what does it carry, and what does it join
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Is a branch of the post division of the mandibular n
Contains GSA fibers carrying general sensation from ant 2/3 of tongue Receives n fibers from chorda tympani |
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Chorda tympani - what is it a br of? what does it carry?
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Is a br of the facial n (CN VII)
Contains: SVA taste fibers from ant 2/3 of tongue Pregang parasymp fibers for submandibular ganglion |
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Where is the submandibular ganglion
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Suspended from lingual n
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Inf alveolar n - where does it go and what does it give rise to
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Is a br of post division of mandibular n
Gives rise to n of mylohyoid Enters mandible through mandibular foramen Courses through mandibular canal and gives rise to inferior dental plexus |
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terminal brs of inf alveolar n
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Incisive n - to mandibular 1st premolar, canine, inciser teeth
Mental n - exits through the mental foramen to supply the chin and lower lip |
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What parts does the CN VIII have
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Cochlear (hearing) and vestibular (equilibrium) parts
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What does CN X innervate
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Abdomen and thorax
mm of soft palate (except tensor veli palatini) mm of pharynx (except stylopharyngeus) mm of larynx provides taste to root of tongue and epiglottis and general sensation to larynx and part of pharynx |
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What does CN XI do
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INnervates the trap and SCMs with GSE
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What does CN XII do
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sends GSE fibers to innervate the extrinsinc and intrinsic muscles of the tongue
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Where are GVE accompanied by GVA
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CN X
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Ganglion and target of CN III
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Ciliary ganglion
Target: Intrinsic eye muscles |
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Ganglion, V branch, and target of CN VII
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Pterygopalatine ganglion
V branch is maxillary Target: Lacrimal gland Nasal cavity Maxillary sinus Palate |
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Ganglion, V branch, and target of CN VII (2nd)
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Submandibular ganglion
Mandibular V branch Target: submandibular sublingual glands |
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Ganglion, V br and target of CN IX
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Otic ganglion
Mandibular V branch Target: Parotid gland |
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Are there parasympathetic nerve fibers part of the trigeminal nerve
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No, but they are distributed to some branches of the trigeminal nerve
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How are the 12 CNs numbered
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In the rostral to caudal sequence that they pierce the dura mater in
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What does CN I do and what is its path
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Functions for smell
SVA fibers arise from olfactory cells in mucosa of nasal cavity and traverse the cribiform plate of the ethmoid bone to reach olfactory bulb in anterior cranial fossa |
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Where is the olfactory tract
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Passes from olfactory bulb to the brain
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What does CN II do
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Functions in vision
Its SSA fibers are formed by the axons of ganglion cells of the nervous retina which converge at the optic disc (papilla) |
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Where do the 2 optic nerves merge
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At the optic chiasm
Fibers from the nasal half of each retina decussate |
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Where are the optic tracts
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Continue posteriorly from the optic chiasm
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What CNs innervate extraocular muscles
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III
IV VI Move the eyeball GSE |
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What does the trigeminal N innervate
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Main sensory n to face
SUpplies most of oral cavity and nasal cavities Innervates mm of masticaion and other mm that develop from 1st arach |
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How many divisions of the sensory part of CN V and where are they
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3 divisions branching from trigeminal ganglion
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What does the trigeminal ganglion contain
|
cell bodies of GSA neurons
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What does V1 supply
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Sensory to orbit, forehead, and dorsum of nose
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What is V1
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Opthalmic nerve
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What is V2
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Maxillary n
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What does V2 supply
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Is sensory nerve to middle of face
GSA fibers for nasal and oral cavities |
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What is V3
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Mandibular division of CN V
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What does V3 supply
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mm of 1st arch (SVE)
Sensory (GSA) to oral cavity, lower 1/3 of face and temple |
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What does VII supply
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muscles of faceial expression
Preganglionic parasympathetic fibers for lacrimal gland and submandibular and sublingual glands Carries taste from anterior 2/3 of tongue |
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What does CN IX
|
carries taste and sensation from oropharynx including posterior 1/3 of tongue
Carries pregang parasympm fibers for supply of parotid gland Innervates stylopharnygeus muscle Provdes GVA fibers for carotid sinus and carotid body |
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What does the VIII carry
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SSA fibers from inner ear to brain
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What is CN V
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trigeminal
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What is CN VI
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abducent
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What is CN VII
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facial
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What is CN VIII
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vestibulocochlear
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What is CN IX
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glossopharyngeal
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What is CN X
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vagus
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What is CN XI
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accessory
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What is CN XII
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hypoglossal
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What are SVE
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Special visceral efferent or brachiomotor (BE) which is motor to skeletal muscle that develops from embryonic pharyngeal arches
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What are SSA
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special somatic afferent for vision, hearing and balance
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What are SVA
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special visceral afferent for smell and taste
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GSE in CNs
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III
IV VI XI XII |
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GVE in CNs
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III
VII IX X |
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GSA in CNs
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V
VII IX X |
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GVA in CNs
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Mainly
IX and X |
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SVE in CNs
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V
VII IX X |
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SSA in CNs
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II
VIII |
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SVA in CNs
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I
VII IX X |
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What is a cranial nerve considered to have
|
Only the functional components that it contains at its attachment to the brain
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What can a branch of a CN contain
|
The functional components that it contains at the location being discussed
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What 2 functional components does CN V has at its attachments to the brain stem
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GSA and SVE
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What fibers does the lingual branch have when traveling with the chorda tympani
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GSA
GVE SVA |
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How do sympathetic GVEs distribute
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To all areas of the head via periarterial nerve plexuses around the external and internal carotid arteries
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What kind of fibers are symp GVEs in the head
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Postganglionic
From cell bodies in superior cervical sympathetic ganglion |
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What are the only CNs with parasymp fibers
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III
VII IX X |
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What is CN I
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olfactory
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What is CN II
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optic
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What is CN III
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oculomotor
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What is CN IV
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trochlear
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What is the path of the facial n
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Exits the cranial cavity through the internal acoustic meatus to enter the facial canal
Descends in facial canal in post wall of middle ear cavity |
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Ganglion of facial n
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Geniculate ganglion at genu of facial n
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Chorda tympani - where does it exit and where does it go
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Br of facial n
Traverses middle ear cavity and exits through petrotympanic fissure into the infratemporal fossa where it joins the lingual n |
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Preganglionic fibers from lingual n
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Exit lingual n in floor of oral cavity to enter submandiblar ganglion where they synapse
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Postganglionic supply of submandibular and sublingual glands
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Supplied either directly or distributed through brs of the lingual n
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What are possible functional components of the lingual n
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Depends on location
GSA only GSA, GVE, SVA GSA, SVA |
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Tympanic br of IX - wht does it carry, where does it go
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Carries preganglionic fibers
Enters tympanic canaliculus Forms tympanic plexus on promontory of middle ear |
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Lesser petrosal n
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Continuation of fibers from tympanic n
Enters middle cranial fossa via hiatus of lesser petrosal n Exits middle cranial fossa through foramen ovale Synapses in otic ganglion |
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Postganglionic fibers from otic ganglion
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Enter main trunk of mandibular division of trigeminal n
Travel with auriculotemporal n Pass into branches to the parotid gland |
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Connections of the submandibular ganglia
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?
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Connections of the otic ganglia
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?
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Symptoms of trigeminal neuralgia or tic douloureux
|
Usually over age 50
Chronic, extreme, sporadic, sudden, burning, stabbing, shock like face pain on 1 side of jaw or cheek few sec or mins per episode; episodes can last for days, weeks, months, and then disappear for years |
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Causes of trigeminal neuralgia or tic douloureux
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Blood vessel pressing on trigeminal n in head as it exits the bloodstream
Part of normal aging process but can be associated with MS |
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Tx for trigeminal neuralgia or tic douloureux
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Anticonvulsants and tricyclic antidepressants
Surgery or stereotactic radiosurgery to destroy part of CN V Acupuncture Biofeedback Vitamins Electrical stim Nutritional therapy |
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Main blood supply to calvaria bone
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Middle meningeal aa
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What do emissary veins do
|
connect scalp veins with dural sinuses providing route for infection
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|
pterion
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Junction of:
Squamous pt of temporal bone Parietal bone frontal bone greater wing of sphenoid bone |
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What do the muscles of mastication develop from
|
1st arches
Innervated by V3 (mandibular division of CN V) |
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What are the masticator muscles
|
Masseter
Temporalis Lateral pterygoid Medial pterygoid |
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What are the temporal and infratemporal fossae
|
Spaces on the side of the head
Are superior and inferior to the zygomatic arch and are connected through the gap deep to it |
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Boundaries of temporal fossa
|
Superiorly and posteriorly:
Inferior and sup. temporal lines Anteriorly: Frontal proc. zygomatic bone Zygomatic pro. frontal bone Floor: Parietal bone Frontal bone Greater wing of sphenoid bone Squamous pt temporal bone |
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What does the temporal fossa contain
|
Junction of:
Frontal bone Parietal bone Greater wing of sphenoid bone Called pterion Meningeal artery may be injured there --> epidural hematoma |
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What limits the temporal fossa laterally
|
Temporal fascia that covers it and partially gives rise to the temporalis muscle
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Where is the tendon for the temporalis muscle
|
Passes deep to zygomatic arch to insert into coronoid process and ramus of mandible
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What does the temporalis do
|
Elevates and retracts the mandible
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Where are the deep temporal nerves and arteries
|
In temporal fossa
Ascend deep to temporalis muscle |
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Where is the zygomaticotemporal nerve and waht does it do
|
It is V2 - cutaneous to anterior temple
In temporal fossa |
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What is superficial to the temporal fossa
|
Superficial temporal arteryu
Transverse facial artery Auriculotemporal nerve |
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Where is the transverse facial artery
|
Branch of superficial temporal a.
Inferior to zygomatic arch |
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Where is the middle temporal artery
|
Branch of superficial temporal a.
Penetrates the muscle to anastomose with the deep temporal arteries |
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Where is the auriculotemporal nerve
|
Ascends with superficial temporal artery and vein
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Path of superficial temporal vein
|
Runs with artery
Joins maxillary vein behind the neck of mandible to form the retromandibular vein, which descends through the parotid gland |
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Path of retromandibular vein
|
Divides into anterior and posterior branches
Anterior branch joins facial v to form common facial v draining into internal jugular Posterior branch joins posterior auricular v to form the external jugular v descending across the SCM |
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What is the infratemporal fossa
|
Irregularly shaped space inferior to the zygomatic arch
|
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|
Boundaries of infratmeporal fossa
|
Laterally by:
Ramus of mandible Medially by: Lateral pterygoid plate Anteriorly by: Maxilla Posteriorly by: tympanic portion styloid pro. of temporal bone Superiorly by: Greater wing of sphenoid bone |
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Where is the masseter muscle
|
Covers the ramus of the mandible laterally
Has superficial and deep parts taking origin from the zygomatic arch Inserts on lateral surface of the ramus and angle of the mandible |
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|
What does the masseter do and what innervates it
|
It elevates the mandible
Innervated by the masseteric nerve |
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|
Communications of the infratemporal fossa
|
Superiorly with:
Temporal fossa, deep to zygomatic arch Superiorly through foramina ovale and spinosum with middle cranial fossa Medially through pterygomaxillary fissure with a deeper space, the pterygopalatine fossa Anterosuperiorly through inferior orbital fissure with orbit |
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|
Contents of infrtemporal fossa
|
Sphenomandibular ligament
Lateral pterygoid m. Medial pterygoid m. Mandibular n & chorda tympani Maxillary a Pterygoid plexus of veins |
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|
Sphenomandibular ligament
|
Is accessory lig
from spine of sphenoid bone to lingula of mandible develops from 1st pharyngeal arch but has little relevance |
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|
Stylomandibular ligament
|
Accessory lig
Represents thickening of parotid fascia between styloid process and angle of mandible Limits extreme protrusion of mandible |
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lateral pterygoid muscle - where is it and what does it do
|
Upper hd from greater wing of sphenoid
Lower hd from lateral pterygoid plate Inserts into capsule and disk of TMJ and neck of mandible Depresses and protrudes mandible U/L contraction shifts the chin to contrlateral side |
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Medial pterygoid m - what are its attachments and actions
|
Supeficial hd from maxillary tuberosity
Deep hd from lateral pterygoid plate Inserts into medial surface of ramus and angle of mandible With masseter, forms a mandibular sling Elevates mandible U/L assists the lateral pterygoid in side to side movement |
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Where does V3 enter the infratemporal fossa
|
Through foramen ovale
|
|
|
What kind of n fibers does V3 have
|
Mixed n - contains SVE and GSA
Innervates msucles of 1st arch |
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|
Branches of V3
|
From trunk - meningeal br and n to medial pterygoid
From ant division muscular brs to masseter, temporalis, lateral pterygoid Buccal branch is only sensory From post division - auriculotemporal, liungual, inferior alveolar (all sensory except mylohyoid br of inf alveolar) |
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|
path of auriculotemporal and what does it carry
|
SPlits around middle meningeal a before exiting infratemporal fossa behind the neck of the mandible
Carries GVE (postgan parasymp) from otic ganglion to parotid gland |
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|
What does the lingual n carry
|
general sensation (GSA) from ant 2/3 of tongue and floor of oral cavity
|
|
|
What joins the lingual n
|
Chorda tympani
They join in the infratemporal fossa |
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|
What does the chorda tympani carry
|
Taste (SVA) from ant 2/3 of tongue and preganglionic parasymp fibers to submandibular ganglion
|
|
|
What does the inferior alveolar n supply
|
Mylohyoid and ant belly of digastric mm via n to mylohyoid
Enters mandibular foramen |
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|
What does the inferior alveolar n carry
|
general sensation (GSA) from mandibular teeth and gingiva
|
|
|
Branches of inferior alveolar n
|
Mental br (terminal)
Incisive n (terminal) |
|
|
What does the mental n supply
|
Carries sensation from mucosa and skin of lower lip and chin
|
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|
What is the maxillary artery a branch of
|
terminal br of external carotid
|
|
|
What does the maxillary artery supply
|
Structures in infratemporal fossa, nasal cavity, oral avity, teeth, dura mater
|
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|
What is the path of maxillary a
|
Traverses infratmeporal fossa lateral or medial to lower hd of lateral pterygoid and passes through pterygomaxillary fissure into pterygopalatine fossa
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|
How is the maxillary artery divided into part
|
In relation to lower hd of lateral pterygoid
2nd pt is lateral or medial to lower hd 3rd pt is mostly in pterygopalatine fossa |
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|
Branches of 1st part of maxillary a
|
Deep auricular
Anterior tympani Inferior alveolar Accessory meningeal (may branch from middle) |
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|
Branches of 2nd pt of maxillary artery
|
Muscular brs to temporalis, pterygoid mm, and masseter
Buccal a to skin, muscle (buccinator) and mucosa of cheek |
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|
Branches of 3rd pt of maxilary a
|
Largely arise in pterygopalatine fossa:
infraorbital to orbiit greater palatine to oral cavity sphenopalatin to nasal cavity pharyngeal to palatovagina can artery of pterygoid canal Includes post sup alveolar a branching near pterygomaxillary fissure to enter infratemporal surface of maxilla |
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|
Pterygoid venous plexus - what does it surround, what does it form, what is its clinical sig
|
Surrounds the lateral pterygoid m
coalesces to form maxillary veins Has clinically important connections via emissary vv with cavernous sinus at base of brain |
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|
What is the TMJ formed between
|
Hd of mandible and squamous portion of temporal bone with articular disc subdividing cavity into upper and lower
|
|
|
Movements of TmJ
|
Hinge movements in lower joint cavity
Gliding movements in upper joint cavity |
|
|
Feautres of squamous pt of tempoiral bone
|
Articular tubercle ant to mandibular fossa
Thin roof of bone separating joint cavity from temporal lobe |
|
|
What does depression of the TMJ involve
|
Opening of jaw
Forward gliding of hd of mandible and articular disc on anterior tubercle Downward rotation of mandible about a horizontal plane through the hd |
|
|
Wwhat does elevation of the TMJ involve
|
Backward gliding of the hd and articular disc on articular tubercle
Upward rotation of mandible |
|
|
Muscles for depression of TMJ
|
Gravity
Lateral pterygoid Accessory mm of mastication (digastric, mylohyoid, geniohyoid) |
|
|
mm for elevation of TMJ
|
Masseter
Temporalis medial pterygoid |
|
|
Protraction of TMJ
|
Mainly lateral pterygoid m w/ some assistance from medial
|
|
|
Retraction of TMJ
|
Contraction of posterior fibers of temporalis and deep pt of masseter
|
|
|
Lateral shift of TMJ
|
Mainly from U/L lateral pterygoid and medial pterygoid contractions
|
|
|
TMJ syndrome
|
Pain and tenderness with chewing
Limited jaw movement Earaches Headaches Dizziness Neck pain and stiffness |
