Head/Eyes/Ears Anatomy

what passes through the zygomaticofacial foramen?

zygomaticofacial nerve

what passes through the patietal foramen

emissary veins

function of occipitofrontalis (frontal belly)

elevates eyebrows and wrinkles forehead; protracts scalp

function of occipitofrontalis (occipital belly)

retracts' scalp; increases effectivness of frontal belly

function of orbicularis oculi (palpebral part)

closes the eyelids gently

function of orbicularis oculi (orbital part)

closes the eyelids forcefully

function of corrugator supercilii

draws eyebrows medially and downward

function of nasalis (trasverse part)

compresses nasal aperature

function of nasalis (alar part)

draws cartilage downward and laterally, opening nostril

function of procerus

draws down medial angle of eyebrows, producing transverse wrinkles over bridge of nose

function of depressor septi

pulls nose inferiorly

function of depressor anguli oris

draws corners of mouth downward and laterally

function of depressor labii inferioris

draws lower lip downward and laterally

function of mentalis

rasies and protrudes lower lip as it wrinkles skin on chin

function of risorius

retracts corner of mouth

function of zygomatic major

draws the corner of the mouth upward and laterally

function of zygomatic minor

draws the upper lip upward

function of levator labii superioris

rasies upper lip; helps form a nasolabial furrow

function of levator labii superioris alaeque nasi

rasies upper lip and opens nostril

function of levator anguli oris

rasies corner of mouth; helps form nasolabial furrow

function of orbicularis oris

closes lip; protrudes lips

function of buccinator

presses the cheek against teeth; compresses distended cheek

function of anterior auricular

draws ear up and forward

function of superior auricular

elevates ear

function of posterior auricular

draws ear upward and backward

function of mentalis

elevates and protrudes lower lip; elevates skin of chin

function of platysma

depresses mandible; tenses skin of inferior face and neck

function of masseter, temporalis, and medial pterygoid

closes jaw

function of lateral pteygoid

opens jaw; allows grinding action side to side, and protrudes the mandible

innervation of the muscles of mastication (masseter, termporalis, medial pterygoid, lateral pterygoid)

mandibular branch of CN V (trigeminal)

branches of the facial nerve

• temporal

• zygomatic

• buccal

• mandibular

• cervical

what does the temporal branch of VII supply?

motor innervation for temple, forehead, superorbital area

what does the zygomatic branch of VII supply?

motor innervation for the infraorbital, lateral nasal, and the upper lip

what does the buccal branch of VII supply?

motor innervation for the cheek, upper lip, and corner of the mouth

what does the mandibular branch of VII supply?

motor innervation for the lower lip and chin

what does the cervical branch of VII supply?

motor innervation for the platysma

what does the opthalmic branch of V supply?

sensory innervation for the anterior scalp, skin of upper eyelid, and bridge of nose

what does the maxillary branch of V supply?

sensory innervation skin of zygomatic arch, skin of macillary region, lower eyelid, part of nospharynx, and upper lip

what does the mandibular branch of V supply?

sensory innervation to the lateral part of scalp, lateral parts of the face anterior to the external acoustic meastus, skin of mandible and lower lip

motor innervation of the muscles of mastication

what does the C2-3 (great auricular) supply?

sensory innervation for the skin over the angle of the mandible

where does the trigeminal nerve supply on the scalp?

sensory innervation for the supratrochlear, supra-orbital, zygomaticotemproal, and auriculotemporal nerves

where do the cervial nerves supply on the scalp?

sensory innervation for the great auricular, lesser occipital, greater occipital, and third occipital nerves

what do the submental nodes drain?

medial part of the lower lip and chin bilaterally

what do the submandibular nodes drain?

medial corner of the orbit, most of the external nose, medial part of the cheek, upper lip, and the lateral part of the lower lip

what do the pre-auricular and parotid nodes drain, and where do they drain to?

• drains most of the eyelids, part of the external nose, and lateral part of the cheek

• drains anterior to the vertex

what do the occipital nodes drain and where do they drain into?

• drains occpital region

• drains into the upper deep cervical nodes

what do the mastoid/post-auricular nodes drain and what do they drain into?

• drains upper part of the scalp, posterior to the vertex

• drains into upper deep cervical nodes

what goes through the optic foramen?

• optic nerve

• opthalmic artery

what goes through the superior orbital fissure?

• superior/inferior branches of the oculomotor nerve

• trochlear nerve

• abducens nerve

• branches of the opthalmic nerve (V1)

• superior opthalmic vein

what is the function of the levator palpebrae superioris & superior tarssal muscle? what innervates them?

elevates the upper eyelid, and is innervated by CN III

function of superior/inferior tarsus

provides support for the eyelid

what is the meibomian/tarsal gland?

• glands within the tarsus

• modified sebaceous glands

• secrete oily substance

function of the oily substance secreted by the glands of the eyes, what glands secrete this?

• increase viscosity of tears

• decrease rate of evaporation

• secreted by lacrimal, meibomian, and conjunctival glands

order that tears go through the eyes

• produced by lacrimal, meibomian, and conjunctival glands

• drains medially through the superior/inferior puncta

• the pass through the lacrimal sac and on inot the nose through the nasolacrimal duct

function and innervation of superior rectus muscle

• elevation with adduction and medial rotation

• innervated by CN III

function and innervation of inferior rectus muscle

• depression with adduction

• innervated by CN III

function and innervation of lateral rectus muscle

• abduction

• innervated by CN VI

function and innervation of medial rectus muscle

• adduction

• innervated by CN III

function and innervation of superior oblique muscle

• depression and abduction with medial rotation

• innervated by CN IV

function and innervation of inferior oblique muscle

• elevation and abduction with lateral roation

• CN III

function of CN II (optic nerve)

sends special sensory innervation from the retina to brain (vision)

what does the CN III (oculomotor) innervate

provides innervation to:

• levator palpebrae superioris muscle

• sphincter pupillae muscle (pupil constriction)

• ciliary body (lens accommodation)

• 4 out of 6 EO muscles

what does the V-1 innervate in regards to the eye?

sensory infromation to the upper/lateral eyelid; sensory innervation ot the lacrimal gland, conjunctiva, cornea

what does the V-2 innervate in regards to the eye?

sensory information to the infra-orbital (lower eyelid)

what does the facial nerve do in regards to the eye on a visceral motor-parasympathetic and motor level?

• visceral motor-parasympathetic: innervation to lacrimal gland (makes you cry)

• motor: innervation to the orbicularis oculi muscle (closes your eyes)

sclera

thick, white, outermost layer; becomes transparent at the cornea

cornea

portion of the sclera in the centeal anterior region that allows light to enter the eye

conjunctiva

clear muscous membrane that covers the sclera

what makes up the uveal tract?

choriod, ciliary body, iris

choroid

• vascular middle layer of the eye that prevents light from scattering inside the eye

• supplies nutrients and oxygen to the retina

ciliary body

• forms complete ring around the eyeball

• accommodation of the lens for near vision (innervated by CN III)

• contribute to the formation of aqueous humor

iris

• anterior to the lens

• color part of the eye

pupil

• opening in the iris that allows light to pass through into eye

• two muscles (sphincter pupillae and dilator pupillae)

lens

• transparents structure held in place by zonular

sphincter pupillae

• pupillary constriction

• innervated by CN III

dilator pupillae

• dilates pupil

• innervated by sympathetic nervous system

what occurs when light goes in the eye (pupilary light reflex)

1. incoming light

2. optic nerve

3. pretectal area of midbrain

4. efferent impulses sent back to eye through oculomotor nerve

5. pupil constriction

anterior vs posterior chamber

• anterior chamber: anterior to the iris

• posterior chamber: posterior to the iris; anterior to the lens

both are filled with aqueous humor, and they are continous through the pupil

viterous humor

• posterior to len and in the vitreous chamber

• gel like substance (helps prevent the eyeball from collapsing inward

retina

• innermost layer (lines 2/3 of the choroid)

• contains millions of rods and cones (photoreceptors that convert light energy into nerve impulses)

• two layers (pigmented and neural layer)

pigmented layer

single layer of melanocytes

neural layer

3 main types of neurons

• photoreceptor cells

• bipolar cells

• ganglion cells

macula leutea

• central part of the retina

• contains the fovea centralis

fovea centralis

• contains only cones

• provides the greatest visual acuity and perception of color

optic nerve

• composed of the retinal cell axons

• sends impulses to the brain

what does the ophthalmic artery branch off from?

internal carotid artery

what branches off of the opthalmic artery?

• lacrimal

• central retinal

• long/short posterior ciliary

• muscular

• medial palpebral

veins of the eye

• superior opthalmic

• inferior opthalmic

how does light travel through the visual field pathway

1. light rays striking the retina generate potentials in the photoreceptors which are sent to the optic nerve

2. impulses pass through the optic nerve and go to the optic chiasm (inner nasal halves cross to the opposite side where they join fibers from the outer temporal halves)

3. optic chiasm then progresses to the optic tracts

4. fibers of the optic tracts synapse in the dorsal lateral geniculate nucleus of the thalamus

5. optic tracts progress to the optic radiation

6. optic radiation progresses to the primary visual cortext in the occipital lobe

hemianopia

defect in half of a visual field

homonymous

defect is on the ssame side of the visual field

heteronymous

defect is on the opposite sides of visual field

what will a lesion of the optic nerve cause?

blindness

what will a lesion of the optic chiasm cause?

bitemporal heteronymous hemianopia

defect in the temporal visual fields of both eyes

what will a lesion of the optic tract cause?

homonymous hemianopia (defect is visual field on the same side of both eyes, ex. lesion on right one will cause visual disturbance of the left visual field of each eye)

what will a lesion of the optic radiation cause?

this is an ocular pathway in the internal capsule, temporal lobe, or occipital lobe homonymous hemianopia (defect is visual field on the same side of both eyes, ex. lesion on right optic tract will cause visual disturbance of the left visual field of each eye)

what eye structures in the eye bend light rays?

• lens

• cornea

• humors

accommodation

• curvature of the lens is adjustable

• allows for focusing on nearby object

convergence

active process of turning the eyes inward to maintain alignment of the visual axes with an object

myopia

• nearsightedness

• globe is too long

• near is clear, distance is blurry

• corrected with concave lens