Eye and Ear Anatomy Lecture Notes

Practice flashcards created from the lecture notes covering key terms and concepts related to the anatomy of the eye and ear.

What is the shape and orientation of the orbits?

The orbits are pyramidal cavities

bases directed anteriorly and apices posteriorly

What part of the orbit is most vulnerable to the spread of diseases from the paranasal sinuses?

medial wall and floor

What part of the orbit is most vulnerable to blowout fractures?

medial wall and floor

What are the primary entrances and exits of the orbit?

optic canal and superior orbital fissure

What structures are most vulnerable to trauma in the orbits?

margins and lateral walls

What makes up the apex of the orbit?

body of sphenoid between optic canal and superior orbital fissure

What makes up the medial wall of the orbit?

frontal process of maxilla

lacrimal bone

orbital plate of ethmoid

body of sphenoid

What makes up the lateral wall of the orbit?

zygomatic bone

orbital surface of greater wing (sphenoid)

What makes up the roof of the orbit?

orbital plate of frontal bone

lesser wing of sphenoid

What makes up the floor of the orbit?

orbital surface of maxilla

zygomatic bone

orbital process of palatine

What makes up the base of the orbit?

frontal bone

maxilla

zygomatic bone

What is the major refractive component of the eyeball?

cornea

What is the result of parasympathetic stimulation of the ciliary body?

reduction of tension on the lens, which allows it to thicken for near vision

What is the result of ciliary body relaxation?

stretching of the lens, which allows far vision

What is the result of parasympathetic stimulation of the iris?

constricts the sphincter, which constricts the pupil

What is the result of sympathetic stimulation of the iris?

dilates the iris, which dilates the pupil

What is the fluid in the anterior segment of the eyeball and where is it produced?

aqueous humor produced by the ciliary process

What is the fluid in the posterior segment of the eyeball and what is its function?

vitreous humor, which acts to maintain eye shape, transmit light, and hold retina in place

Which layer of the eyeball is responsible for providing nourishment to photoreceptors?

The middle vascular layer, which includes the choroid.

Where do the recti muscles originate and insert?

origin- annular tendinous ring

insert- posterior to the limbus on the sclera

Where does the superior oblique originate and insert?

origin- body of sphenoid

insert- sclera

Where does the inferior oblique originate and insert?

origin- maxilla

insert- sclera

Where does the levator palpebrae superioris originate and insert?

origin- lesser wing of sphenous

insert- superior lamina

What EOMs are not supplied by CN3? What is their innervation?

lateral rectus CN6

superior oblique CN4

Which nerves supply the muscles of the orbit?

CN3

What is the action of superior rectus?

elevation

adduction

intorsion (medial rotation)

What is the action of inferior rectus?

depression

adduction

extorsion (lateral rotation)

What is the action of superior oblique?

depression

abduction

intorsion (medial rotation)

What is the action of inferior oblique?

elevation

abduction

extorsion (lateral rotation)

What is the action of medial rectus?

adduction

What is the action of lateral rectus?

abduction

What is the action of levator palpebrae superioris?

elevate upper eyelid

What artery supplies extra-ocular circulation?

ophthalmic artery

infraorbital artery

What artery supplies intra-ocular circulation?

ophthalmic artery

What is the drainage of ophthalmic veins?

facial vein anteriorly

cavernous sinus posteriorly

pterygoid plexus inferiorly

What is involved in the fracture of the medial wall of the orbit?

ethmoid sinus

sphenoid sinus

What is involved in the fracture of the inferior wall/floor of the orbit?

maxillary sinus

What are the signs of Central Retinal Artery Occlusion?

marked afferent pupillary defect

retinal whitening

cherry red spot at macula

AV narrowing

What is the sensory innervation of the external ear?

CN V (great auricular nerve)

CN VII and CN X

What does the tympanic membrane do?

Converts airborne sound waves into vibrations transmitted to the ossicles of the middle ear

What innervates the mucosa of the ear and ear canal?

CN IX

What innervates the neuroepithelial crests and maculae?

vestibular part of CN VIII

What is the role of the cochlea?

It is involved in converting sound waves into neural impulses.

What is the smallest bone in the body?

stapes