External Anatomy of the Skull and Face

scalp

multi-layered soft tissue structure covering the skull

how does the scalp extend from anterior to posterior

superior orbital margins (anteriorly) to superior nuchal lines (posteriorly)

how does the scalp extend bilaterally

to the temporal lines

what does the scalp protect

the skull and provides a framework for hair growth

what is significant about the first three layers of the scalp

bound together and move as a whole on the skull

5 layers of the scalp

skin

connective tissue of superficial fascia

aponeurosis of occipitofrontalis muscle

loose connective tissue

periosteum of skull bones

what is contained within the skin of the scalp?

sweat/sebaceous glands, hair follicles, arteries and veins, good lymphatic drainage, sensory nerve endings (highly sensitive to touch and pain)

the connective tissue of superficial fascia is thick and contains a good supply of..

cutaneous nerves

connective tissue of superficial fascia has robust vascular supply but what is the issues?

cannot retract when injured due to density of surrounding tissue so you get prolonged bleeding when injured

aponeurosis of occipitofrontalis muscle/galea aponeurotica/epicranial aponeurosis

a strong tendinous sheath that covers the calveria

what does the aponeurosis of occipitofrontalis muscle do

connects the frontalis muscle (anteriorly) to the occipitalis muscle posteriorly and allows movement of the scalp

what does the loose (areolar) connective tissue do

-structural support, allowing for movement while maintaining organization

-serves as a reservoir for water and salts, maintaining tissue hydration

-allows for diffusion of oxygen/nutrients from capillaries to cells, and removal of metabolic waste

-supports body's immune and inflammatory responses

-allows free movement of the upper three layers over the pericranium/skull

how does loose (areolar) CT help body's immune and inflammatory

responses

contains various immune cells that quickly respond to pathogens breaching epithelial surfaces

loose (areolar) CT has small blood vessels that communicate with the

intracranial venous system through emissary veins that is often called the danger area, why?

as infections on the scalp can spread into the cranial cavity

what is the last layer of the scalp, made from periosteum of the cranial bones

pericarnium

what does the pericarnium do

provides vascular supply to the outer surface of the cranial bones

pericarnium can form new bone in response to..

injury

muscles of mastication are innervated by what nerve...

mandibular nerve, a branch of the trigeminal nerve

muscles of mastication

temporalis, masseter, medial pterygoid, lateral pterygoid

what is the strongest muscle that elevates the mandible

masseter

what are the two parts of the masseter

superficial and deep

where is the superficial part of the masseter

attaches to maxillary process of the zygomatic bone

where is the deep part of the masseter

attaches to zygomatic arch of the temporal bone

both parts of masseter attach to the ramus of the...

mandible

where is the temporalis muscle

sits within the temporal fossa on lateral aspect of skull

since the temporalis muscle attaches to the coronoid process of the mandible, the fan like fiber directions allow for...

elevation AND retraction of mandible

what overlies the temporalis muscle

temporal fascia

what is temporal fascia used for

a myringoplasty where it is harvested and used to repair a perforated TM

what does the medial pterygoid do

functions to assist in elevating the mandible with two heads

where is the medial pterygoid in relation to the lateral pterygoid

lies inferior to the lateral pterygoid

where is the lateral pterygoid

located superior and more superficial to the medial pterygoid with two heads

muscle fibers of lateral pterygoid are horizontal which allows for what actions?

-with bilateral movements, you get protraction of the mandible

-with unilateral movements, you get 'side to side' movement of the jaw

all muscles of facial expression are innervated by what nerve?

branches of facial nerve (CN VII)

what muscles are in the orbital group of facial expression

orbicularis oculi, corrugator supercilii

what muscles are in the nasal group of facial expression

nasalis, procerus, depressor septi nasi

what muscles are in the oral group of facial expression

orbicularis oris, buccinator, minor groups that raise or lower lips

orbicularis oculi

circumferentially surrounds the eye socket and covers the eyelid

what are the three parts of orbicularis oculi

orbital, palpebral, lacrimal

orbital part of orbicularis oculi

pulls skin of forehead, temple, and cheek like a purse string; pulls eye closed TAUT

palpebral part of orbicularis oculi

gently closes lids so no other tissues are affected

lacrimal part of orbicularis oculi

empties tears from the lacrimal sac

facial nerve injury is secondary to..

trauma, infection or idiopathic

what happens with facial nerve injury

weakness or paralysis of muscles

what is the only muscle group that closes the eye

orbicularis oculi

a drooping upper lid can result in dry eye called...

exposure keratitis

if you have a drooping lower lid with eversion, what is that called

ectropion

if you have ectropion, what happens

tears cannot drain properly causing irritation or corneal abrasion

whre is the corrugator supercilii

located deep to the orbicularis oculi, superomedial

what does corrugator supercilii do

draws eyebrows together and downward

corrugator supercilii can create vertical wrinkles called..

glabellar lines which is associated with frowning and suffering

where is the procerus

L=located medially over glabella

what does procerus do

-functions to depress medial end of eyebrow

-contributes to wrinkling skin over glabella along with corrugator supercilii

where is the nasalis

covers the dorsum of the nose

what does nasalis do

-functions to dilate/flare the nostrils and wrinkle the nasal skin

-notable during deep breathing or intense emotions

what does the medial fibers of depressor septi nasi do

pull the nasal septum inferiorly to constrict the nasal opening

what does the lateral fibers of depressor septi nasi do

assist nasalis in widening nasal opening

oral group is used for facial expression and what other actions

singing, whistling, and speech

orbicularis oris

circumferential muscle acts as main sphincter of the lips

what does orbicularis oris do when contracted

closes the lips to narrow the opening of the mouth

where is the buccinator

located deep to the other muscles of the face and runs between maxilla and mandible

what does buccinator do

functions to pull the cheeks inward, assists during whistling or playing instrument

buccinator helps prevent what..

food accumulation/"pocketing" of food

the upper group of minor oral muscles do what?

elevates the lips

the lower group of minor oral muscles do what?

depresses the lips

blood supply to the head and face run through the neck and comes from what vessel

common carotid artery

the left common carotid is a direct branch of the ascending ______ while the right common carotid comes off the _______ trunk

aorta, brachiocephalic

where is the common carotid artery

deep to the inferior end of the SCM

where are the internal and external carotid arteries

at about the level of the laryngeal prominence

where do internal and external carotid arteries bifurcate

carotid sinus and body (CNIX)

the internal carotid artery begins at the levle of the upper border of...

thyroid cartilage

path of the internal carotid artery

ascends through the neck in the carotid sheath with the internal

jugular vein and vagus nerve

does the internal carotid artery have branches in the neck

none

internal carotid artery branches make up the anterior circulation of the brain in the...

circle of wills

external carotid artery begins around the upper border of the...

thyroid cartilage

where does external carotid artery terminate

parotid salivary gland where it divides into

terminal branches

what are the terminal branches of external carotid artery

superficial temporal, maxillary

where can you feel pulsations of external carotid artery

as it emerges from under the anterior border of the SCM and lies within the carotid triangle

branches of external carotid artery supply the anterior neck, face and scalp, what does it NOT supply

orbit and part of forehead which is supplied by supraorbital artery

what are the three anterior branches of external carotid artery

superior thyroid artery, lingual artery, facial artery

what are the one medial branche of external carotid artery

ascending pharyngeal artery

what are the two posterior branches of external carotid artery

occipital artery, posterior auricular artery

what are the two terminal branches of external carotid artery

superficial temporal artery, maxillary artery

what are the branches of the external carotid artery supplies the face

superficial temporal, maxillary, facial, lingual

what are the branches of the internal carotid artery supplies the face

supratrochlear artery, supraorbital artery

clood to face & scalp will drain into analogous veins to the..

arterial supply

what forms the external jugular vein

union of posterior auricular vein & retromandibular

vein

what forms the retromandibular

vein

maxillary and superficial temporal veins

external jugular vein will drian back into the...

subclavian veins

what is the largest vein of the head and neck

internal jugular vein

internal jugular vein collects blood from the...

brain, face and neck

internal jugular vein receives blood from what veins to drain the anterior face

facial and lingual veins,

where is the internal jugular vein

lies in carotid sheath with carotid artery

and vagus nerve

where does the internal jugular vein join the subclavian vein to form the

brachiocephalic vein

medial end of the clavicle

where is the danger triangle

area from corners of the mouth to bridge of the nose

what vein has direct communication with cavernous sinus

facial vein

what are the risk with the direct communication of facial vein and cavernous sinus

potential spread of

infection to the CNS skin punctures/cuts, pimple popping, nasal hair removal, dental procedures

if you have an infection from the cavernous sinus, what can happen

cavernous venous thrombosis, meningitis, or abscess formation