Orbit and EOM

Question 1

What bones contribute to the roof of the orbit?

Answer 1

Orbital plate of the frontal bone, lesser wing of the sphenoid

Question 2

What bones contribute to the floor of the orbit?

Answer 2

Orbital process of the maxilla, orbital process of the palatine bone, zygomatic bone

Question 3

What bones contribute to the lateral wall of the orbit?

Answer 3

Zygomatic bone, greater wing of the sphenoid

Question 4

What bones contribute to the medial wall of the orbit?

Answer 4

Frontal process of maxilla, lacrimal bone, orbital plate of ethmoid, body of sphenoid

Question 5

What is the periorbita?

Answer 5

It is continuous with the periosteum of the dura mater and forms the fascial sheath around the eyeball

Question 6

What are the two portions of conjunctiva?

Answer 6

Palpebral and bulbar

Question 7

What is the role of the tarsal glands?

Answer 7

make lipid secretions to lubricate the edges of the eyes

Question 8

What are the roles of the lacrimal lake, caruncle, and punctum?

Answer 8

Lake= tear reservoir of about 7-10 microliters
Caruncle=globular nodule with oil and sweat glands
Punctum=collects excess tears and drains them down the lacrimal duct

Question 9

What are the sclera and cornea?

Answer 9

Sclera=fibrous coat over posterior 5/6 of eye and is opaque

Cornea=transparent anterior 1/6 of the eye

Question 10

What structures have their origin in the annular tendon?

Answer 10

the 4 recti and the levator palpebrae superioris

Question 11

What roles do the superiors/inferiors have when the eye is adducted?

Answer 11

Superior oblique–elevates
Inferior oblique–depresses
Superior rectus–intorts
Inferior rectus–extorts

Question 12

What roles do the superiors/inferiors have when the eye is abducted?

Answer 12

Superior oblique–intorts
Inferior oblique–extorts
Superior rectus–elevates
Inferior rectus–depresses

Question 13

What roles do the superiors/inferiors have when the eye is in primary position?

Answer 13

Obliques abduct/recti adduct
Superiors intort/inferiors extort
SR/IO elevate//IR/SO depress

Question 14

What areas does the ophthalmic nerve supply?

Answer 14

Sensation to the eyeball, conjunctiva, forehead, frontal region, ethmoid sinuses

Question 15

What does the lacrimal nerve supply?

Answer 15

Sensation from upper eyelid, conjunctiva, and lacrimal gland

Question 16

What do the frontal nerve branches supply?

Answer 16

The supraorbital supplies the forehead and scalp

The supratrochlear supplies the sensory bridge of the nose, medial upper eyelid, medial forehead

Question 17

What are the main branches of the nasocilliary nerves?

Answer 17

Anterior ethmoid (anterior air cells, nasal cavity), posterior ethmoid (air cells), long cilliary (sensory to cornea, sclera, and conjunctiva) and short cilliary (carries postganglionic fibers of CN III)

Question 18

What is the maxillary nerve’s contribution to the orbit?

Answer 18

The zygomatic lacrimal nerve carries postganglionic fibers of the facial nerve to the lacrimal gland

Question 19

What structures enter the orbit outside of the tendinous ring?

Answer 19

Frontal nerve, lacrimal nerve, trochlear nerve, ophthalmic veins