Test 178  (Ocular anatomy)

1. The superior ophthalmic vein: 

a. is larger than the inferior ophthalmic vein

b. receives vortex veins from the upper part of the eyeball

c. is formed by the union of supraorbital vein and lacrimal 
   vein

d. leaves the orbit through the upper part of the superior 
    orbital fissure

e. normally receives the inferior ophthalmic vein before 
    entering the cavernous sinus
 

Answera.T   b.T  c.F   d.T  e.F
It is formed by the union of supraorbital vein and the facial vein. It normally enters the cavernous 
sinus without receiving the inferior ophthalmic vein.

2. The ciliary epithelium:

a. contains an inner pigmented layer made up of cuboidal
    cells

b. contains two layer of cells with apices facing each other

c. contains an outer layer which is continuous with the 
    retinal pigment epithelium

d. is involved in aqueous production

e. contains blood vessels between its two layers
 

Answera.F  b.T  c.T  d.T  e.F
The ciliary epithelium contains an outer pigmented cuboidal layer and an inner non-pigmented layer. Embryologically, the layers are derived from the optic cup.
 
 

3. The ethmoidal sinuses:

a. are usually three numbers on either side

b. can be found extending into adjacent bones

c. all drained into the medial meatus

d. are related superiorly to the anterior cranial fossa

e. are separated from the orbit by a thick wall
 

Answer
a.F   b.T  c.F  d.T  e.F
The number of ethmoidal sinuses is variable and can 
be grouped into anterior, middle and posterior ethmoidal sinuses. They are separated from the orbit by a thin bone. The anterior and middle ethmoidal sinuses drain into the middle meatus and the posterior ethmoidal sinuses drain into the superior meatus.

 

. 4. The lacrimal nerve:

a. is the smallest of the three branches of the ophthalmic 
    nerve

b. contains motor nerve that supplies the smooth muscle of
    the lacrimal gland

c. receives parasympathetic nerve fibres from the facial 
    nerve

d. enters the orbit through the tendinous ring

e. gives sensory supply to the skin of the eyelid and the 
    conjunctiva
 

Answer
a.T  b.F  c.T  d.F  e.T
The lacrimal nerve is a pure sensory nerve. It enters 
the orbit through the superior orbital fissure outside the tendinous ring.

5. The circle of Zinn:

a. is formed from anastomosis of the long posterior ciliary 
    arteries 

b. supplies the outer layer of the retina

c. supplies blood to the intraorbital part of the optic nerve

d. is formed at the outer layer of the choroid

e. sometime gives rise to cilioretinal artery that supplies the
    macula
 

Answer
a.F   b.F  c.F  d.F  e.T
The circle of Zinn is formed from branches of the short posterior ciliary arteries. It is formed at the sclera and supplies the intraocular part of the optic nerve.

 

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