Test 182  (Ocular anatomy)

1. The following are true about the trigeminal nerve: 

a. it is a pure sensory nerve

b. the trigeminal ganglion contains cell bodies of the 
    trigeminal nerve

c. the main sensory nucleus receives fibres subserving 
    pain and temperature

d. the spinal nucleus receives fibres subserving touch and 
    pressure

e. the sensory fibres of the ophthalmic nerve enters the 
    inferior part of the spinal nucleus
 

Answera.F   b.T  c.F   d.F  e.T
The ophthalmic and maxillary branches of the trigeminal nerve are pure sensory nerve but the mandibular division contains both sensory and motor nerves. The main sensory nucleus receives fibres serving touch and pressure and the spinal nucleus receives fibres serving pain and temperature.

2. In the cavernous sinus:

a. the oculomotor nerve lies superior to the trochlear nerve

b. the abducent nerve is medial to the internal carotid 
    artery

c. the maxillary division of the trigeminal lies below the 
    ophthalmic division of the trigeminal nerve

d. the oculomotor nerve divides into two division on the 
    lateral wall of the cavernous sinus

e. the trochlear nerve passes through the cavernous sinus 
    to enter the orbit
 

Answera.T  b.F  c.F  d.F  e.F
In the lateral wall of the cavernous sinus lies the following structures from superior to inferior position: 
oculomotor nerve, trochlear nerve, ophthalmic division 
of the trigeminal nerve and maxillary division of the trigeminal nerve. The internal carotid artery, the carotid sympathetic nerve plexus and the abducent nerve pass through the cavernous sinus. The abducent nerve lies inferolateral to the internal carotid artery. 

 
 

3. The annulus of Zinn (common tendinous ring) is attached to:

a. lesser wing of the sphenoid bone

b. greater wing of the sphenoid bone

c. ethmoid bone

d. zygomatic bone

e. lacrimal bone
 

Answer
a.T   b.T  c.T  d.F  e.F
The annulus of Zinn is attached to the lesser and 
greater wings of sphenoid bone and the orbital plate of the ethmoid.

 

. 4. The lesser wing of the sphenoid bone provides attachment to
      the following muscle:

a. the levator palpebrae superioris

b. the superior oblique muscle

c. the inferior oblique muscle

d. lateral rectus muscle

e. superior rectus muscle
 

Answer
a.T  b.T  c.F  d.F  e.T
The lateral rectus muscle has two heads and both arise from the greater wing of the sphenoid bone. The inferior oblique originates from the floor of the orbit.

5. Structures that do not enter the orbit through the annulus of Zinn 
    include:

a. nasociliary nerve

b. inferior ophthalmic vein 

c. superior ophthalmic vein

d. lacrimal nerve

e. inferior division of the oculomotor nerve
 

Answer
a.F   b.T  c.T  d.T e.F
Structures outside the annulus of Zinn include: lacrimal nerve, frontal nerve, superior and inferior ophthalmic artery.
.

 

More MCQs