External Eye

What are the 6 extrinsic muscles of the eye?

Superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique

Which cranial nerve innervates the lateral rectus?

CN VI Abducens nerve

What is the action of the lateral rectus?

Abducts the eye (turns it laterally)

What cranial nerve innervates the superior oblique?

CN IV Trochlear nerve

What is the action of the superior oblique?

Depresses the eye and turns it medially

Damage to which cranial nerve would impair most extrinsic eye muscles?

CN III Oculomotor nerve

What are the palpebrae?

Eyelids - protection and help distribute tears

What is the pathway of lacrimal fluid to the nasal cavity?

Lacrimal gland > across the eye from lateral to medial > lacrimal puncta > lacrimal canaliculi > lacrimal sac and nasolacrimal duct > nasal cavity

What is the sclera continuous with anteriorly?

The cornea

What layer of the eye do the sclera and cornea belong to?

The outer or fibrous layer of the eye

What is the iris?

The colored portion of the eye

What is the opening at the center of the iris called?

The pupil

What is the biconvex structure responsible for focusing light on the retina?

The lens

What structures change the shape of the lens?

Ciliary body: ciliary muscles and suspensory ligaments (zonular ligaments/ciliary zonule)