Main Body: Head and Neck

mental line

angle of mandible-mastoid process-superior nuchal line that distinguishes the head from the neck

jugular notch

line from the clavicle-acromion-horizontal line around C7, distinguishes the neck from the thorax

maxillary, nasal, zygomatic, palatine, lacrimal, inferior nasal conchae

fascial bones

frontal, parietal, occipital, and sphenoid

bones of the neurocranium

supra-orbital foramen 

small hole above the orbit where the opthalamic branch of the trigeminal nerve (V1) exits the skull 

infra-orbital foramen

small hole below the orbit where the maxillary branch (V2) of the trigeminal nerve exits the skull

mental foramen

small hole on the on either side of the mandible underneath alveloar part where the mandibular branch of the trigeminal nerve exits (V3) the skull

superior and inferior orbital fissures

holes in the back of the orbit various nerves exit to innervate the eye

hyoid bone

small U shaped bone that serves as a strong bony anchor for several muscles and soft tissue structures in the head and neck (suprahyoid, infrahyoid, pharyngeal, extrinsic muscles of the tongue)

CN VII 

innervates all the muscles of facial expression, has zygomatic, buccal, cervical, and marginal mandibular branches, as well as temporal and posterior auricular, emerges from the stylomastoid foramen 

muscles of facial expression

thin and flat, insert on skin, some may arise from bone or skin or fascia, vasculature comes from the facial artery and vein, and are named by their actions

bells palsy

only the facial nerve is affected, occurs due to excessive autoimmine response such as recent viral infection, see drooping of the right side of mouth, loss of orbicularis oculi tone causing inability to lubricate the right eye

muscles of mastication

include the massater, lateral and medial pterygoids, temporalis, responsible for chewing movement of the mandible at the temporomandibular joint, innervated by CN V (trigeminal)

stylomastoid foramen

where the facial nerve exits the skull, then goes on to innervates all the muscles of fascial expression

temporal fossa

where the temporalis and masseter originate from 

infratemporal fossa

where the lateral and medial pterygoids originate from

temporalis

O: temporal fossa

I: coronoid process of mandible

Inn: mandibular division of CN V (V3)

A: 1) closes mandible (elevation) 2) retracts mandible (retrusion) 3) lateral movement (grinding)

masseter

O: zygomatic arch

I: ramus of mandible

Inn: mandibular division of CN V (V3)

A: 1) closes mandible (elevation), 2) protracts mandible 3) deep fibers retract mandible and grind/chew

lateral pterygoid

O: lateral pterygoid plate (on sphenoid bone)

I: neck of mandible and TMJ capsule

Inn: mandibular branch of CV V (V3)

A: 1) opens mandible 2) bilateral= protrusion of mandible 3) ipsalateral contraction= contralateral deviation

medial pterygoid 

O: medial surface of lateral pterygoid plate 

I: ramus of mandible, inner surface 

Inn: mandibular division of CN V (V3)

A: closes mandible, protrusion, contralateral deviation 

trigeminal nerve

CN V, has 3 divisions- opthalmic division, maxillary division, and mandibular division, innervates glands, sensory, and motor

temporomandibular joints

allow opening and closing of the mouth and complex chewing of side to side movement of the lower jaw, synovial joint, formed between the head of the mandible and the articular fossa and articular tubercle of the temporal bone

lower part of TMJ

allows for mainly hinge like depression and elevation of the mandible

upper part of TMJ

allows the head of the mandible to protrude onto the articular tubercle and retract into the mandibular fossa

facial layers of the neck 

superficial, deep investing, carotid sheath, prevertebral, pretracheal 

compartmental layers of neck

visceral, vascular, vertebral

frontalis

attaches from the front of the skull to the aponeurosis of the skull, wrinkles the skin of the forehead

orbicularis oculi

surrounds the orbit and eye, responsible for blinking and squinting

zygomaticus major

attaches from corner of the mouth and attaches on the zygomatic bone (high on the cheekbone), minor is found just medially and superior to it, activates in wide smiling

levator anguli oris

reaches up from the corned of the mouth to the midway between the mouth and eye, raises the corner of the mouth into a snarl

orbicularis oris 

surrounds the mouth, responsible for making an o with the lips 

depressor anguli oris

attaches from the corner of the mouth and inferior to the mandible, responsible for bringing the corner of the mouth down into a pout

depressor labii inferioris

attaches to either side of the bottom of the mouth medial to depressor anguli oris and bringing the lower lip inferior

mentalis

attaches from the chin undernear depressor labii inferioris, wrinkles the chin

platysma

thin and superficial muscle over either side of the neck, “duck muscle”

risorius 

attaches from the corner of the mouth to the side of the cheek, responsible for pulling mouth laterally 

buccinator

muscle deeper in the cheek, assists in tightening the cheek when making an o with mouth

levator labii superioris 

attaches from top of mouth more medial to the levator anguli oris and attaches to below the orbit, raises top lip into a snarl as well 

auricularis anterior, superior, and posterior

muscles surrounding the ear, many people cannot move them voluntarily

occipitalis

attacges to the aponeurosis of skull anteriorly and posteriorly

external carotid artery branches

superficial temporal artery, maxillary artery, facial artery

vertebral compartment of the neck 

contains the cervical vertebrae and associated postural muscles 

visceral compartment of the neck

contains important glands (thyroid, parathyroid, thymus) and parts of the respiratory and digestive tracts that pass between the head and thorax

vascular compartment of the neck

2 compartments, one on each side, contains major blood vessels and the vagus nerve

layer 1: superficial fascia

contains the platysma

platysma

slightly wrinkles the surface o the skin of the neck, depresses the lower jaw, draws down the lower lip and angle of the mouth and is innervated by CN VII (cervical branch)

layer 2 of the neck

deep investing fascia, contains the sternocleidomastoid and trapezius 

sternocleidomastoid

PA: mastoid process/lateral nuchal line

DA: medial clavicle, manubrium

Inn: CN XI for efferent (motor), C3, C4 for afferent (sensory)

A: unilateral: ipsalateral sidebend and contralateral rotation, bilateral: upper cervical extension and lower cervical flexion

Reverse action: secondary inspiration

forward head

how tight SCM or poor posture might present

torticollis

occurs when there is tightness unilaterally in the SCM, tightness on the R side will tilt the right ear towards the right shoulder and the nose and face will rotate towards the left (happens in babies usually)

layer 3 of the neck

prevertebral, consists of the scalenes, the levator scapulae, longus coli, longus capitis, paraspinals, phrenic nerve, and the branchial plexus

longus capitis 

PA: occipital bone 

DA: C3-C6 anterior portion of transverse processes 

Inn: C3-5 ventral rami 

A: neck/head flexion

longus colli

PA: anterior tubercle C1 and bodies of C1-3 and tp of C3-6

DA: bodies C5-T3, tp C3-5

Inn: C2-6 ventral rami

A: bilateral: flexes neck, unilateral: neck/head flexion with ipsilateral rotations

rectus capitis anterior

small muscles on the sides of the neck right beneath skull, aids in flexion of the head and neck

rectus capitis lateralis 

stabilizes the head and weakly assists with lateral flexion of the head 

ansa cervicalis

part of the cervical plexus, is the primary motor nerves to the strap muscles of the neck

levator scapulae

PA: tp of C1-C4

DA: vertebral border of the scapula between the spine and the superior angle

Inn: dorsal scapular nerve (from ventral ramus C4, C5)

A: elevation of the scapula, downward rotation of the scapula

reverse action: ispilateral side bend and rotation

anterior scalene

PA: tp of mid cervical vertebrae

DA: 1st rib

Inn: ventral rami of C4-6

A: raises 1st rib, ipsilateral beck side bend

middle scalene

PA: most cervical tps

DA: 1st rib

Inn: ventral rami of most cervical nerves

A: raises 1st rib, ispilateral neck side bend

posterior scalene

PA: most cervical tps

DA: 2nd rib

Inn: ventral rami of most cervical nerves

A: raises second rib, ispilateral neck side bend

obliquus capitis inferior 

PA: posterior tubercle of C2

DA: transverse process of C1

Inn: suboccipital nerve (C1)

A: head extension and rotation 

obliquus capitis superior 

PA: transverse process of C1

DA: between superior and inferior nuchal line 

Inn: suboccipital nerve (C1)

A: head extension and rotation 

rectus capitis posterior major

PA: inferior nuchal line

DA: C2 spinous processes

Inn: suboccipital nerve (C1)

A: head extension and head rotation

rectus capitis posterior minor

PA: posterior tubercle of C1 (atlas)

DA: inferior nuchal line of occipital bone

Inn: suboccipital nerve (C1)

A: head extension

occipital neuralgia

is suboccipital tissue is tight, compression of the suboccipital nerve can occur- results in substantial pain and discomfort- headaches! 

compression of C1-2

see headaches in the posterior portion of the neck on the ispilateral side 

compression of C2-C3

headaches that radiate towards the front of the skull/forehead

layer 4 of the neck

pretracheal, find the infra and suprahyoid muscles in this layer, as well as neurovasculature of the neck

nerves of the neck

cervical plexus, brachial plexus, phrenic nerve, sympathetic chain

structures of the vascular compartment

carotid artery, jugular vein, vagus nerve

carotid arteries origins

right common carotid originates from teh right brachiocephalic trunk, left common carotid is a direct branch from the arch of the aorta, 

common carotid

branches into the internal and external carotid

carotid sinus

found at the bifurcation of the common carotid, exists at the bottom of the internal carotid artery- contains receptors that monitor homeostatic changes in partial pressure of oxygen, CO2, pH, and is innervated by a branch of the glossopharyngeal nerve (X)

vagus nerve

exits the jugular foramen between glossopharyngeal and accessory nerves (X and XI), branches include the pharyngeal branch, superior laryngeal nerve (which has a internal and external branch), and the recurrent laryngeal nerve

visceral compartment structures 

pharynx and esophagus, larynx and trachea, thyroid gland 

pharynx compartments

nasopharynx, oropharynx, laryngopharynx

thyroid cartilage

forms the adam’s apple