Eye Anatomy

Question 1

Bones of the Orbit

Answer 1

1. Frontal
2. Lacrimal
3. Ethmoid
4. Palatine
5. Maxilla
6. Zygomatic
7. Sphenoid

Question 2

Walls of the Orbit

Answer 2

1. Superior wall: Frontal, lesser wing of Sphenoid
2. Medial wall: Ethmoid, Lacrimal, Maxilla, Sphenoid
3. Inferior wall (weakest! “blowout fracture”): Zygomatic, Maxilla, Palatine
4. Lateral wall (strongest!): Zygomatic, greater wing of Sphenoid

Question 3

Optic Canal

Location ?

Transmits?

Answer 3

Location: apex of orbit

Transmits: Optic Nerve, Ophthalmic Artery

Question 4

Superior Orbital Fissure

Location?

Transmits?

Answer 4

Location: between roof/lateral wall of orbit

between greater and lesser wing of the Sphenoid bone

Transmits: Superior and Inferior Ophthalmic Veins

CN III, IV, VI

Branches of CN V-1 (lacrimal, frontal, nasociliary nerves)

Question 5

Inferior Orbital Fissure

Location?

Transmits?

Answer 5

Location: between floor and lateral wall of the orbit

formed by Sphenoid bone

Transmits: Infraorbital Artery

Infraorbital branch of Maxiallary Nerve (V-2)

Question 6

Supraorbital Foramen/Notch

Location?

Transmits?

Answer 6

Location: In the frontal bone above orbit

Trasmits: Supraorbital Nerve and vessels

Question 7

Infraorbital Foramen

Location?

Transmits?

Answer 7

Location: In Maxillary bone under orbit

Transmits: Infraorbital Nerve and vessels

Question 8

Anterior/Posterior Ethmoidal Foramen

Location?

Transmits?

Answer 8

Location: In Ethmoid Bone

Transmits: Ethmoidal Arteries and Nerves

Question 9

Two muscles of the Iris

Answer 9

1. Sphincter Pupillae (constrictor) muscle

miosis (constriction of pupil)

2. Dilator Pupillae muscle

mydriasis (dilation of pupil)

Question 10

Sphincter Pupillae Muscle

1. Function?
2. Autonomic?

2a? What nerve?

2b? What ganglion?

Answer 10

1. alters the size of the pupil in response to light–Constricts; controls the amounter of light entering the eye
2. Parasympathetic
   2a. Occulomotor Nerve (CN III)

2b? Ciliary Ganglion

Question 11

Dilator Pupillae Muscle

1. Autonomic?

1a? What nerve?

1b? What ganglion?

Answer 11

1. Sympathetics
   1a. Long ciliary nerves
   1b. Superior Cervical Ganglion

Question 12

Parts of the Outer Fibrous Tunic

Answer 12

1. Sclera
2. Cornea
3. Limbus

Question 13

Parts of the Uvea (vascular tunic)

Answer 13

1. Choroid: vascular layer; provides the outer retina with nutrients
2. Ciliary Body: complex and smooth muscles and vessels
3. Iris

Question 14

Ciliary Muscle

1. Function?
2. Autonomics?
   2a. what nerve?
   2b. Nucleus and ganglion?
3. Associated Clinical condition?

Answer 14

1. accommodation of lens; works as a sphincter; when contracts, it lessens the tension of the suspensory ligament so the lens becomes more rounded–Accommodation reflex
2. Parasympathetic
   2a. Occulomotor Nerve (CN III)
   2b. Edinger-Westphal (CN III) Nucleus and Ciliary ganglion
3. Presbyopia; By age 45, the ability of the lens to become more rounded is lost

Question 15

Ciliary Body

1. Function?
2. Route of Aqueous Humor?
3. Dysfunction?

Answer 15

1. Secrete Aqueous humor
2. Ciliary body –> Posterior chamber –> Anterior chamber –> drained at the Iridocorneal Angle –> Canal of Schlemm –> Venous system
3. Rates of production and absorption out of balance –> Increased Intraoccular pressure –> Glaucoma –> severe blindness

Question 16

Parts of the Tunica Interna

Answer 16

1. Retina (pars optica)
2. Retina (pars cecum)

Question 17

Parts of the Retina Pars Optica

Answer 17

1. Optic Disc “blind spot” optic nerve and central artery leave the eye
2. Macula Lutea
3. Fovea Centralis

Question 18

Parts of the Retina Pars Cecum

Answer 18

1. Iridial Retina behind the iris
2. Ciliary Retina behind the ciliary body

Light-insensitive

Question 19

Extraocular Muscles

Answer 19

1. Levator Palpebral Superioris (LPS)
2. Lateral Rectus
3. Medial Rectus
4. Superior Rectus
5. Inferior Rectus
6. Superior Oblique
7. Inferior Oblique

Question 20

Lateral Rectus Muscle

1. Innervation?
2. Function?

Answer 20

1. CN VI (LR₆SO₄)₃
2. Directs the pupil laterally

Abduct the pupil

Question 21

Medial Rectus

1. Innervation?
2. Function?

Answer 21

1. CN III
2. Direct the pupil medially

Adduct the pupil

Question 22

Superior Rectus

1. Innervation?
2. Function?

Answer 22

1. CN III
2. Elevate the pupil

Assist in turning pupil medially

Question 23

Inferior Rectus

1. Innervation?
2. Function?

Answer 23

1. CN III
2. Depress the pupil

Assist in turning the pupil MEDIALLY

Question 24

Superior Oblique

1. Origin
2. Innervation?
3. Function?

Answer 24

1. Posterior orbit, just below LPS
2. CN IV
3. DEPRESSES the pupil

Assists in turning pupil laterally

Question 25

Inferior Oblique 1. Origin 2. Innervation? 3. Function?

Answer 25

1. Floor of the orbit 2. CN III 3. ELEVATE the pupil Assist in turning pupil laterally

Question 26

Parasympathetic route of eye

Answer 26

Edinger-Westphal Nucleus --\> **CN III** --\> Ciliary Ganglion --\> Short ciliary nerves (V1) --\> Ciliary Muscle and Spincter Pupillae CN III : Parasympathetics

Question 27

Branches of Trigeminal _Cranial_ Nerve | (Ophthalmic Division)

Answer 27

1. Frontal: supraorbital and supratrochlear branches 2. Lacrimal: to lacrimal gland 3. Nasociliary: Long and short ciliary, Infratrochlear, ethmoidal (anterior and posterior)

Question 28

Structures **through** Anulus Tendineus

Answer 28

1. Occulomotor Nerve (CN III) 2. Nasocilieary branch of CN V1 3. Abducens Nerve (CN VI) 4. Optic Nerve (CN II) 5. Ophthalmic _Artery_

Question 29

Structures **Above** Anulus Tendineus

Answer 29

1. Trochlear Nerve (CN IV) 2. Frontal Branch of V1 3. Lacrimal Branch of V1 4. Ophthalmic _Vein_

Question 30

Branches of Ophthalmic Artery (branch of Internal Carotid Artery)

Answer 30

1. **Central Retinal Artery obstruction** leads to instant and complete blindness 2. Lacrimal Artery 3. Long & Short Posterior Ciliary Arteries 4. Superior & Inferior Muscular Branches 5. Supraorbital Artery 6. Anterior & Posterior Ethmoidal Arteries 7. Superior & Inferior Palpebral Arteries 8. Supratrochlear (Frontal) Artery 9. Dorsal Nasal Artery

Question 31

Ophthalmic Veins Drainage?

Answer 31

1. Superior Ophthalmic Vein drains into the Cavernous Sinus 2. Inferior Ophthalmic Vein drains into the Pterygoid Venous Plexus

Question 32

Refractory Media All of the transparents structures through which light passes to reach the retina

Answer 32

1. Cornea 2. Aqueous Humor 3. Lens 4. Vitroeous Chamber