Head And Neck: Muscles, Blood Vessels, And Nerves

Front 1

Muscles of facial expression

x 4

Back 1

- all have origins from bony skull - insert into subcutaneous tissue & skin of face, head,& neck
- most muscles are thin and latral borders often distinct
- all inervated by facial Nerve CN VII

Front 2

Orbicularis Oculi Muscle

Back 2

muscle of eye region
a) broad, circular layer of muscle that surrounds eye region and passes through upper & lower eyelids; closes eyelids

Front 3

Orbicularis Oris M.

Back 3

muscle of mouth
1) sphincter muscle of mouth - fibers encircle mouth, passing through upper and lower lips; closes mouth (lips)
2) deeper muscle fibers contiuous laterally with buccinator muscle

Front 4

Buccinator M

Back 4

muscle of cheek
1) muscle that forms wall of cheek
2) attaches superioly to maxilla & inferiorly to lateral mandible
3) fibers pass into upper & lower lips (deep to orbicularis oris muscle)
4) Compresses cheek and aids in keeping food between teeth during chewing

Front 5

Platysma M

Back 5

muscle of the neck
a) thin subcutaneous muscle that covers anterior neck
b) runs from fascia of upper chest - attaches to border of mandible and lower lip
c) flattens skin of neck; draws corners of mouth downward

Front 6

Parotid Gland

Back 6

1) largest of the 3 salivary glands - fills retromandibular space posterior to mandibular ramus
a) parotid duct crosses over masseter muscle & through wall of cheek into oral cavity
b) all branches of facial nerve (CN VII) to facial muscles pass through parotid gland

Front 7

Nerves of the Facial Region
x 2

1) Facial Nerve CN VII

Back 7

motor to; stylohyoid muscle, posterior belly of digastric muscle, and all muscles of facial nerve
a) exits sylomastoid foramen on base of skull
b) main trunk passes through parotid gland, where it divides into several branches
c) branches fan out across face and neck to supply muscles of facial expression

Front 8

Nerves of the Facial Region
x 2

2) Trigemminal Nerve CN V

Back 8

sensory to face and anterior head
a) cutaneous nerve to skin of face and scalp, nasal and oral cavities, teeth, sinuses, and eye
b) before exiting cranial cavity, nerve divides into 3 divisions:

Front 9

Trigeminal Nerve CN V 1

Opthalmic Division

Back 9

sensory to forehead, upper eyelid, anterior nose
a) exits via superior orbital fissure - runs along roof of orbit
b) terminal branch = supraorbital nerve; emerges at supraorbital notch (foramen); sensory to forehead and anterior scalp

Front 10

Trigeminal Nerve CN V 2

Maxillary Division

Back 10

sensory to lower eyelid , anterior cheek, lateral nose, upper lip, upper lip, upper teeth, & hard palate
a) exits via foramen rotundum
b) terminal branch = infraorbital nerve - emerges at infraorbital foramen; sensory to anterior cheek, lower eyelid, lateral nose, & upper lip

Front 11

Trigeminal Nerve CN V 3

Mandibular Division

Back 11

sensory to lateral cheek (inner & outer walls) , lower teeth, anterior 2/3 of tongue, chin, jaw, temporomandibular joint, lateral scalp
a) exits via foramen ovale
b) terminal branch = inferior alveolar nerve - passes into mandibular foramen then through mandibular canal - sensory to teeth of lower jaw
c) terminal branch = mental nerve - emerges at mental foramen; sensory to chin
d) also provides motor branches to muscles of mastication, mylohyoid muscle and anterior belly of digastric muscle

Front 12

Temporal Fossa

Back 12

upper, lateral skull, superior to level of zygomatic arch
a) contains temporalis muscle

Front 13

Infratemporal Fossa

Back 13

a) space deep (medial) to ramus of mandible
b) bounded superiorly by base of skull, anteriorly by maxilla bone, medially by pharynx, and lateral pterygoid bone, and laterally by mandible
c) contains medial & lateral pterygoid muscles

Front 14

Muscles of mastication

Back 14

- 4 muscles: all insert onto mandible
- all inervated by mandibular dividion of trigeminal nerve CN V 3

Front 15

1) Temporalis

Back 15

Origin -temporal fossa and overlying fscia
Insert - coronoid process & ramus of mandible (fibers pass downward, medial to zygomatic arch)
Action - a) aanterior fibers oriented vertically - elevate mandible; close the mouth
b) posterior fibers oriented obliquely downward and forward - retractable mandible
c) primary muscle for maintaining closed (resting) position of mandible

Front 16

2) Masseter Muscle

Back 16

powerful biting muscle
Origin - from zygomatic arch
Insert - fibers run downward to lateral ramus & angle of the mandible
Action - raises mandible

Front 17

3) Medial Pterygoid Muscle

Back 17

in same position as masseter, but on medial side of mandible
Origin - medial side of lateral pterygoid plate
Insert - fibers run obliquely downward, backward, & lateral to inner side of mandibular angle & ramus
Actions - raises, protrudes, and adducts mandible toward midline

Front 18

4) Lateral Pterygoid Muscle

Back 18

- fibers run anterior to posterior, high in infratemporal fossa, deep to temporalis muscle
Origin - from lateral side of lateral pterygoid plate
Insert - mandibular neck and articular disc of temporomandibular joint
Actions - protrudes jaw; contributes to adduction of jaw; opens mouth

Front 19

Actions of muscles mastication

Back 19

a) opening - closing mouth:
1) masseter, temporalis & medial pterygoid - powerful closers of jaw (biting)
2) lateral pterygoid - opens mouth; assisted by anterior-posterior bellies of digastric
b) chewing (grinding of food) involves combination of lateral motions and alternating anterior-posterior (protrusion-retrusion) motion of jaw
c) lateral motion - medial & lateral pterygoid muscles adduct jaw on same side
1) proper synchronization between sides produces lateral grinding motion
d) anterior-posterior motion
1) temporalis - chief retractor of jaw & maintains resting position of jaw
2) protrusion of jaw by medial pterygoid and lateral pterygoid muscles
e) chewing assisted by tongue (postions food between teeth) and buccinator muscle (maintain food between teeth)

Front 20

Temporomandibular Joint (TMJ)

Back 20

1) articulation between head (condyle) of mandible and mandibular fossa of temporal bone at base of cranium
a) articular surfaces seperated by articular disc made of dense fibrocartilage - increase congruency (fit) between bony surfaces
2) during open/closing of mouth, mandible rotates
a) condyle of mandible slides anteriorly in mandibular fossa, then downward onto articular tubercle
b) axis of rotation for mandible at lingula of mandible - medial side, senter of ramus
1) a strong ligament spans from base of skull to the lingula - anchors mandible at that point and serves as axis of mandibular rotation during opening/closing
c) produces both mouth opening and downward movement of jaw to seperate teeth
d) opening produced by pull of lateral pterygoid muscle on articular disc & neck of mandible

Front 21

Triangles of Neck

Back 21

divided into Anterior and Posterior Triangles by sternocleidomastoid muscle

Front 22

Sternocleidomastoid Muscle

Back 22

Origin - from manubrium (superior end) of sternum and medial clavicle
Insert - mastoid process of skull
Innerv - Accessory CN XI
Action - unilateral - turns head and lifts chin toward opposite side of muscle
bilateral - lifts chin and flexes neck so that chin is thrust forward

Front 23

Anterior Triangle

Back 23

sternocleidomastoid muscle, mandible, and anterior mid-line of neck
a) contain submandibular salivary gland, common carotid artery, nternal jugular vein, vagus & hypoglossal nerves, suprahyoid & infrahyoid muscles, and thyroid gland
1) Thyroid gland - bi-lobed endocrine gland located on either side of trachea near base of neck; thyroid hormone regulates overall metabolic rate

Front 24

Posterior Triangle

Back 24

clavicle, sternocleidomastoid, & trapezius muscles
a) contains external jugular vein, subclavian artery and vein, accessory nerve CN XI, and cutaneous nerves for anterior and posterior neck

Front 25

suprahyoid muscles

Back 25

elevaet hyoid bone; assist in swallowing & phonation
- hyoid bone serves as base for muscles of tongue

Front 26

Digastric Muscle

Back 26

2 bellied muscle
Origin - Anterior belly - from inner side of anterior mandible (near midline)
Posterior Belly - from mastoid process
Insert - 2 bellies joined together by intermediete tendon; tendon connected (held down) to hyoid bone by fascia sling (tendon not directly attached to hyoid bone)
Innerv - anterior belly - mandibular division of trigeminal nerve CN V 3 (with mylohyoid muscle)
posterior belly - facial nerve CN VII (with styloid muscle)

Front 27

Stylohyoid Muscle te

Back 27

Origin - styloid process of skull
Insert - hyoid bone
- styloid runs deep & parallel o the posterior belly of digastric muscle
Innerv - facial nerve (with posterior belly of digastric muscle)

Front 28

Mylohyoid Muscle

Back 28

Origin - mylohyoid line of medial (inner) surface of mandible
Insert - into muscle of opposite side to form mylohyoid raphe - raphe runs down midline from anterior mandible to hyoid bone
Innerv - mandibular division of trigeminal nerve CN V 3 (with anterior belly of digastric muscle)
- muscle fibers run from lateral to medial, meeting at midline raphe
- forms floor of oral cavity; supports tongue, submandibular & sublingual glands

Front 29

Actions of Suprahyoid muscle

Back 29

a) during swallowing, elevate tongue and floor of mouth to move food into pharynx
b) with food in pharynx, stylohyoid and posterior digastric elevate and retract tongue & hyoid bone, preventing return of ood into mouth
c) suprahyoid muscles also elevate larynx - larynx elevates during swallowing which aids in closing it off during swallowing, thus preventing unwanted material from entering larynx

Front 30

Infrahyoid Muscles

Back 30

- several thin, flat muscles in anterior triangle of neck
- act to stabilize or depress hyoid bone and tongue
- most also depress larynx (one elevates larynx)
- all innervate by branch of cervical plexus
- serve to depress and stabilize the hyoid bone, tongue, and larynx

Front 31

Omohyoid Muscle -

Back 31

- 2 bellied muscle (omo = "shoulder")
Origin - medial end of superior border of scapula
Insert - hyoid bone
- muscle has superior and inferior bellies, joined at mid-point by intermediate tendon
- passes deep to clavicle and sternocleidomastoid muscle
- intermediate tendon held to clavivle via fascia sling (muscle does not attach to clavicle)
Action: depress hyoid bone

Front 32

Sternohyoid

Back 32

Origin - sternum
Insert - hyoid bone
Action - depresses hyoid bone

Front 33

Sternothyroid

Back 33

Origin - sternum
Insert - thyroid cartilage of larynx (largest cartilage of larynx; V-shaped; in male: "Adam's Apple")
Action - depresses larynx

Front 34

Thyrohyoid

Back 34

Origin - thyroid cartilage of larynx
Insert - hyoid bone
Action - elevates larynx or depresses hyoid (depending on which of these structures is anchored or not anchored in position by the action of other muscles)

Front 35

Scalene Muscles

Back 35

deep muscles that span from cervical vertebrae to first and second ribs

Front 36

Anterior Scalene

Back 36

origin - middle cervical vertebrae
Insert - anterior part of rib 1
Action - elevate ribs 1 and 2 during forced inspiration; laterally flex neck

Front 37

Posterior-Middle Scalene

Back 37

- 2 muscles fused together; forms largest muscle of group
Origin -all cervical vertebrae
Insert - lateral part of ribs 1 and 2

Front 38

Interscalene Triangle

Back 38

- space defined by anterior scalene muscle, 1st rib, and posterior-middle scalene muscle
a) allows for passage of subclavian artery and spinal nerves of brachial plexus

Front 39

Aortic Arch

Back 39

lies behind manubrium of sternum - gives off 3 branches
a) brachiocephalic artery (trunk) - divides into:
1) right common carotid artery - passes superiorly into anterior triangle of neck
2) right subclavian artery - passes behind (deep to) clavicle and through interscalene triangle
b) left common carotid artery - directly off arch of aorta
c) left subclavian artery - directly off arch of aorta

Front 40

Common Carotid Artery

Back 40

runs superiorly, deep to anterior border of sternocleidomastoid muscle
a) runs in carotid sheath 9connective tissue compartment of neck) with internal jugular vein and vagus CN X Nerve
b) internal carotid artery - no branches in neck; continues with carotid sheath, then enters carotid canal of skull & supplies brain via cerebral arterial circle

Front 41

External Carotid Artery

1 of 2

Back 41

1) blood supply for neck, face, & head (all structures external to cranial cavity, except eye)
2) exits carotid sheath and runs superiorly - passes deep to posterior belly of digastric muscle & posterior to mandible; runs deep to parotid gland within retromandibular space
3) branches of external carotid artery
a) ligual artery - suppies tongue and sublingual gland
b) facial artery - crosses inferior border of mandible; supplies submandibular gland & face

Front 42

External Carotid Artery

2 of 2

Back 42

4) external carotid terminates by dividing into:
a) superficial temporal artery - ascends to temporalis muscle & temporal fossa region
b) maxillary artery - runs anteriorly, passing deep to mandible to enter infratemporal fossa region; sends branches to muscles of mastication & intomaxilla bone
1) middle meningeal artery - from maxillary artery; ascends through foramen spinosum to supply cranial dura mater

Front 43

Subclavian Artery

Back 43

1) arches laterally across root of neck
a) through interscalene triangle, between anterior & posterior-middle scalene muscles
b) crosses over 1st rib - name changes to axillary artery

Front 44

Branches of Subclavian Artery

Back 44

a) vertebral artery
1) runs superiorly within transverse foramen of cervical vertebrae
2) enters foramen magnum of skull - vertebrals join to form basilar artery of brain
b) Internal thoracic artery
1) runs inferiorly along inner side of the anterior thoracic wall (to either side of sternum)
2) provides branches to thoracic wall
c) other branches of subclavian artery supply inferior neck & scapular regions

Front 45

External jugular Vein

Back 45

- superficial vein of neck (unaccompanied by artery)
a) begins at inferior ear (behind mandible - deep to parotid gland)
b) runs inferiorly, superficial to sternocleidomastoid muscle - drains into subclavian vein

Front 46

Internal jugular vein

Back 46

- venous drainage from brain and cranial dura mater
a) begins at jugular foramen of skull
b) runs inferiorly in carotid sheath with internal or common carotid artery and vagus nerve
c) passes deep to sternocleidomastoid muscle
d) joins with subclavian vein to form brachiocephalic vein

Front 47

Subclavian Vein

Back 47

a) continuation of axillary vein from upper limb (name changes at first rib)
b) passes superficial to anterior scalene muscle (does not pass through interscalene triangle) - subclavian artery & vein seperated by anterior scalene muscle

Front 48

Brachiocephalic Vein

Back 48

a) formed by junction of internal jugular vein and subclavian vein
b) right & left brachiocephalic veins join together to form superior vena cave - drains into the heart