Anatomy Head And Neck Laitman Lab Q's Vol Iii

Front 1

What is the "ansa cervicalis"? Where will you locate it?

Back 1

Ansa Cervicalis: (Ansa: Latin, loop) looping nerve in carotid triangle; innervates all infrahyoid muscles (sternohyoid, sternothyroid, omohyoid) except thyrohyoid;
- Superior Root: mainly fibers from C1 adherent to CN XII
- Inferior Root: fibers from C2-3; descends from superior neck region to join superior root;

Front 2

Which larger nerve is the external laryngeal nerve a branch of? What is the function of the external laryngeal nerve?

Back 2

External Laryngeal N. – branch of Superior Laryngeal N. which is a branch of Vagus N. (CN X); descends posterior to sternothyroid muscle in company with superior thyroid a. supplies cricothyroid muscle and adjacent part of inferior constrictor of pharynx

Front 3

What are the components of the "carotid sheath"?

Back 3

Carotid Sheath – tubular, dense fibrous investment that extends from base of cranium to root of neck; blends anteriorly with investing and pretracheal layers of fascia and posteriorly with prevertebral layer of deep cervical fascia;
- Contents:
o common (inferiorly) and internal (superiorly) carotid arteries
o internal jugular vein (IJV)
o Vagus N. (CN X)
- Associated with:
o Deep cervical lymph nodes
o Carotid sinus nerve
o Carotid periarterial branches of sympathetic nerves

Front 4

Where is the hyoid bone? Does it articulate directly with any other bones? What does it do? Where did it arise from embryologically?

Back 4

Hyoid Bone
– located in anterolateral part of neck;
– does NOT articulate with any other bones;
– provides attachments for hyoid muscles which steady and move hyoid bone and larynx;
– arises from second branchial arch

Front 5

Identify the thyroid gland. Does your cadaver have a pronounced pyramidal lobe, accessory thyroid tissue or a remnant of the thyroglossal duct? Where would you
expect to find these structures, if present, and why?

Back 5

Thyroid Gland
- lies deep to sternothyroid and sternohyoid muscles from level of C5 to T1 vertebrae
- consists of right and left lobes, anterolateral to larynx and trachea
o Pyramidal Lobe – present in 50% of cases; small prominence on superior surface of isthmus of gland usually to left of median plane;
o Accessory Tissue – may develop in neck lateral to thyroid cartilage, usually on thyrohyoid muscle; functional yet not often sufficient to maintain normal function if thyroid gland is removed
o Thyroglossal Duct – transitory endodermal tube extending from posterior tongue region of embryo carrying thyroid forming tissue at its descending distal end; pyramidal lobe and accessory thyroid tissue are remnants of thyroglossal duct
- largest endocrine gland
- produces thyroid hormone, which controls rate of metabolism, and calcitonin, a hormone controlling calcium metabolism

Front 6

What is "special" about the innervation of the cricothyroid muscles of the larynx?

Back 6

All intrinsic muscles of larynx are innervated by recurrent laryngeal nerve EXCEPT the cricothyroid, which is innervated by the external laryngeal nerve.

Front 7

Through which structure would you perform an emergency procedure to allow air to get into the respiratory tract if the laryngeal vestibule was blocked? Why would you take this route?

Back 7

Simplest and most rapid access to airway inferior to vocal cords created by opening cricothyroid membrane (i.e. cricothyrotomy); Recall following anatomical relationships to avoid complication:
- inferior thyroid veins arise from thyroid plexus of veins and descend on anterolateral surface of trachea
- small thyroid ima artery may be present and ascend to the isthmus os the thyroid gland
- left brachiocephalic vein, jugular venous arch and pleurae may be encountered
- trachea is small, mobile and soft in infants, making it easy to cut through posterior wall and create fistular communication with esophagus

Front 8

What is the function of the nerve to the mylohyoid? What larger nerve is it a branch of?

Back 8

Mylohyoid Muscle – elevates hyoid bone, floor of mouth, and tongue during swallowing and speaking; supplied by mylohyoid nerve (branch of inferior alveolar nerve of CN V3)

Front 9

What is the relationship of the thyroid gland to the thyroid cartilage of the larynx?

Back 9

Thyroid gland is inferior to the thyroid cartilage.

Front 10

What are the "boundaries" of the root of the neck (also referred to as the thoraco-cervical region)?

Back 10

Root of the Neck – junction between thorax and neck; opens into Superior Thoracic Aperture; Boundaries:
- Laterally – first pair of ribs
- Anteriorly – manubrium of sternum and costal cartilages
- Posteriorly – body of T1 vertebra

Front 11

Where does the thoracic duct drain into? Are there differences between lymphatic drainage on the right and left sides of the head and neck? If so, what are they?

Back 11

Thoracic duct drains into origin of left brachiocephalic vein. Thoracic duct drains entire body save for the right upper extremity, right side of thorax and right side of head and neck which are drained through right lympatic duct.

Front 12

Can you describe an external carotid – subclavian anastomosis (e.g., anastomosis between a branch of the external carotid with a branch of the subclavian system)?

Back 12

Subclavian a. → costocervical trunk → deep cervical a. → occipital a. → external carotid a.

OR

Subclavian a. → vertebral a. → occipital a. → external carotid a.

Front 13

Spend a few moments looking at your styloid process. What muscles/ligaments arise from this process? Where do these structures arise from embryologically?

Back 13

Styloid Process – Second (Hyoid) Branchial Arch

Stylomandibular ligament – ?
Stylohyoid ligament – ?

Styloglossus muscle – ?
Stylohyoideus muscle – ?
Stylopharyngeus muscle – Third Branchial Arch

Front 14

What is the relationship of the extracranial portion of the facial nerve to the parotid gland? What could happen to the facial nerve if you perform a total parotidectomy on a patient? What would this mean functionally for the patient?

Back 14

Facial N. (CN VII) – extracranial portion within parotid gland
- nerve could accidentally be damaged during parotidectomy which would cause patient to lose motor control of muscles of facial expression on that side of face

Front 15

What is the primary type of nerve fiber in the extracranial portion of the facial nerve?

Back 15

SVE – motor to facial muscles (branchial arch derived)

Front 16

What is the relationship of the external carotid artery to the parotid gland?

Back 16

The external carotid a. passes deep to the mandible while the parotid gland is superficial to it.

Front 17

What is the auriculotemporal nerve a branch of? If this nerve was damaged, could it affect the function of the parotid gland? Why?

Back 17

Auriculotemporal n. – branch of Mandibular n. (CN V3); conveys secretory (parasympathetic) fibers originating from glossopharyngeal n. (CN IX) via otic ganglion; sensory fibers to gland carried by great auricular and auriculotemporal n.

Yes, damage to auriculotemporal n. would affect function of parotid gland.

Front 18

Please use this lab to review cervical branches of the subclavian system of arteries as well as continuing to visualize external carotid branches.

Back 18

Obviously.

Front 19

What are the muscles of mastication? What are they dervived from embryologically? What type of nerve fiber innervates them? Which cranial nerve innervates them?

Back 19

- Muscles of Mastication:
o Temporalis
o Masseter
o Pterygoid lateral (only opener of jaw)
o Pterygoid medial
- Derived from First Branchial Arch
- Innervation: SVE fibers from CN V3 – Mandibular N.

Front 20

Where does the temporalis muscle arise from? Insert on to? What is its function?

Back 20

Temporalis Muscle
- Origin: floor of temporal fossa and deep surface of temporal fascia
- Instertion: tip and medial surface of coronoid process and anterior border of ramus of mandible
- Function: elevates mandible, closing jaws; its posterior fibers retrude mandible after protrusion

Front 21

Where would a dentist perform a "mandibular block"? What nerve would the dentist be targeting? What would be the result of a successful block?

Back 21

Mandibular Nerve Block
- anesthetic injected adjacent to mandibular nerve where it enters infratemporal fossa
- Target: Mandibular N.
- Success: anesthetize auriculotemporal, inferior alveolar, lingual and buccal branches of mandibular n.

Front 22

Where does the inferior alveolar nerve enter the mandible? What type of fibers are in this nerve? Where does it emerge?

Back 22

Inferior Alveolar Nerve (branch of V3)
- Enters mandibular canal via mandibular foramen
- Terminal branch (Mental N.) exits via mental foramen
- Fibers: GSA (to teeth of mandible via dental plexus and skin of chin via mental nerve ) and SVE (to Mylohyoid muscle and anterior belly of digastric via nerve to mylohyoid)

Front 23

What embryonic cartilage serves as a primordium for aspects of mandibular development? Is this cartilage related to a branchial arch?

Back 23

Meckel’s Cartilage – First branchial arch

Front 24

What larger nerve is the chorda tympani a branch off of? What type of fibers are in this nerve? Which nerve will the chorda tympani join? What is the "sister" nerve of the
chorda tympani (i.e., a nerve with the same functions and same parent nerve only serving a different area)?

Back 24

Chorda Timpani
- Branch of Facial Nerve (CN VII)
- Carries taste fibers (SVA) from anterior 2/3 of tongue
- “Hitching a Ride:” presynaptic parasympathetic secretomotor fibers (GVE) for submandibular and sublingual salivary glands
- Joins lingual nerve in infratemporal fossa
- Sister Nerve: Glossopharyngeal Nerve (CN IX) ????

Front 25

From where does the chorda tympani nerve exit the skull? Where does it go from there? (Make sure that you can trace the pathway of this nerve).

Back 25

Chorda tympani arises from CN VII just superior to stylomastoid foramen. . .crosses tympanic cavity medial to handle of malleus. . .passes through the petrotympanic fissure between the tympanic and petrous parts of the temporal bone to join the lingual nerve (CN V3) in the infratemporal fossa. . .parasympathetic fibers of the chorda tympani synapse in the submandibular ganglion. . .post-synaptic fibers follow arteries to glands

Front 26

What type of joint is the temporomandibular joint? The atlanto-occipital? The atlanto-axial?

Back 26

Temporomandibular Joint
- modified hinge type synovial joint
- articular surfaces: head of mandible, articular tubercle of temporal bone, mandibular fossa

Atlanto-Occipital Joint
- between the atlas (C1) and occipital bone
- synovial joint with no IV disc

Atlanto-Axial Joint
- between C1 and C2
- synovial joint with no IV disc

Front 27

CILIARY GANGLION – Eyes (Iris)

Back 27

Motor Root - Preganglionic parasympathetic fibers carried in Oculomotor nerve (C.N. III).
Sensory Root - Nasociliary nerve (V1).
Sympathetic Root - Carotid plexus via plexus around opthalmic artery.
Distribution Root - Nasociliary nerve branches (V1). Para-Sphinct Pup/ciliaris m. Symp-iris, ciliary body, cornea

Front 28

PTERYGOPALATINE GANGLION – Lacrimal gland

Back 28

Motor Root - Preganglionic parasympathetic fibers in greater petrosal nerve (br. C.N. VII). Joins with deep petrosal n to form nerve of pterygoid canal.
Sensory Root - Main trunk V2.
Sympathetic Root –Deep petrosal nerve off internal carotid plexus.
Distribution Root - Branches of V2 direct or comm to lacrimal gl/secretomor to palate, nasal cavity, pharynx.

Front 29

SUBMANDIBULAR GANGLION – Submandibular Gland

Back 29

1. Motor Root - Preganglionic parasympathetic fibers carried in chorda tympani nerve (br. C.N. VII) to lingual nerve (V3).
2. Sensory Root - Lingual N (V3).
3. Sympathetic Root - From sympathetic plexus on facial artery.
4. Distribution Root - Terminal branches of lingual N (V3) to sublingual and submandibular glands.

Front 30

OTIC GANGLION – Parotid Gland

Back 30

1. Motor Root - Preganglionic parasympathetic fibers carried in the lesser petrosal nerve (br. C.N. IX).
2. Sensory Root - Mandibular nerve (V3).
3. Sympathetic Root - From plexus on middle meningeal artery.
4. Distribution Root - Via communicating branches to the auriculotemporal nerve (V3) to parotid gland.