Opthal

Question 1

What are the bones of the orbit?

Answer 1

7:
Frontal, zygomatic, maxillary, sphenoid, ethmoid, lacrimal, palatine

Question 2

What are the 7 muscles of the eye?
Innervation?

Answer 2

Levator palebrae superioris
Superior + inferior rectus
Medial + lateral rectus
Inferior + superior oblique

LR6, SO4
The rest (including levator palebrae superioris by CNIII)

Question 3

What are the eye signs of CN4 and CN6 palsy?

Answer 3

LR 6, SO4

Lateral Rectus - abducts eye (moves it laterally)
Thus, CN6 (abducens) nerve palsy results in esotropia (eye turned in)

Superior Oblique - medial rotation, abducts and depresses eye –> inferolateral gaze
Thus, CN4 (trochlear) nerve palsy results in hypertropia (eye drifts or looks up) and excyclotorsion (outward rotation of eye)

Question 4

What is the sensory innervation of the eye?

Answer 4

Provided by 1st branch (V1 - Ophthalmic branch) of Trigeminal Nerve (CN5)

3 Branches of V1: Lacrimal (extraconal), Frontal (extraconal), Nasociliary (sensation to cornea, peri-limbal conjunctiva, superior-medial conjunctiva)

Question 5

What is the motor innervation to the eye? Which is intra vs extraconal?

Answer 5

All CNIII (oculomotor) except Superior Oblique (CN4 trochlear) and Lateral Rectus (CN6 abducens)

CN4 extraconal, rest intraconal via superior orbital fissure.

Question 6

What is normal IOP?

Answer 6

10-20mmHg