Test 205  (Ocular anatomy)

1. The following are true about the inferior ophthalmic vein:

a. it receives blood from the facial vein and the angular 
    vein

b. it receives more tributaries than the superior ophthalmic 
   vein

c. it runs below the inferior rectus to enter the cavernous 
    sinus

d. it communicates with the superior ophthalmic vein at 
    the superior ophthalmic fissure

e. it has communication with the pterygoid plexus

 
Answera.T  b.F  c.F  d.F  e.T
The inferior ophthalmic vein has less tributaries than
the superior ophthalmic vein. It runs above the inferior rectus to enter the cavernous sinus. It communicates with the superior ophthalmic vein and the pterygoid plexus at the inferior orbital fissure.
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2. The pterygopalatine ganglion:

a. is suspended from the mandibular nerve

b. receives the greater petrosal nerve that contains 
    parasympathetic nerve for the lacrimal gland.

c. supplies motor nerve to the orbicularis oculi

d. provides sensory supply to the frontal sinus

e. provides sensory supply to the nasal mucosa
 

Answera.F  b.T  c.F  d.F  e.T
The pterygoid ganglion is suspended from the maxillary nerve. Orbicularis oculi is supplied by the facial nerve. Frontal sinus is supplied by branches of the ophthalmic branch of the trigeminal nerve. 
 
 

3. The ophthalmic artery:

a. is the first branch of the internal carotid artery after
    it passes through the cavernous sinus.

b. passes forward in the orbit between the lateral 
    rectus and the optic nerve

c. crosses the optic nerve inferiorly within the orbit in 
    the majority of patients.

d.  lies within the dura as it transverses the optic canal

e. terminates as the supratrochlear and dorsal nasal 
    arteries

 
Answer
a.T   b.T  c.F  d.T  e.T
The ophthalmic artery is the first branch of the internal carotid artery after it passes through the cavernous sinus. The artery crosses the optic nerve superiorly within the orbit in the majority of patients. It terminates as the supratrochlear and dorsal nasal arteries.
 

. 4. True statements about the inferior oblique muscle:

a. it arises from the lacrimal bone

b. it passes anterolaterally below the inferior rectus.

c. it is innervated by the inferior division of the third nerve

d. it intorts the globe

e. it elevates the globe
 

Answer
a.F  b.F  c.T  d.F  e.T
It arises from the maxilla and passes posterolaterally 
below the inferior rectus. It elevates and extorts the globe.

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5. The following are true about the cones:

a. there are about 5 millions cones in a human retina

b. the blue cone is the least common of the three different
    cones

c. the red and green cones made up 90% of all cones

d. blue cones are absent in the fovea

e. red and green cones are responsible for the highest 
    degree of visual acuity in bright light

 
Answer
a.T   b.T  c.T  d.T  e.T
There are about 5 million cones in a human retina. Blue cones being the least common (about 10% of all cones) 
and red and green cones the most common (together 
making up 90% of all cones). Red and green cones are responsible for the highest degree of visual acuity in bright light because the rods are insensitive in light and the blue cones are affected by chromatic aberration.

 

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