Test 151  (Ocular anatomy )

1. The lacrimal sac:

a. is posterior to the orbital septum

b. is surrounded by orbital fat

c. contains fundus which is situated above the common 
    canaliculus 

d. is weaker below than above the medial canthal tendon

e. is widest where common canaliculus enters the sac 
 

Answer
a.F   b.F   c.T    d.T   e.F
The lacrimal sac is anterior to the orbital septum
even though it is in the orbit. Orbital fat is only found 
postero-lateral to the sac. Above the medial canthal 
tendon, the sac is covered by the lacrimal fascia and the tendon whereas below it, the sac is covered only 
by the lacrimal sac. Therefore, the lacrimal sac is 
weaker below than above the medial canthus. The sac is widest a few millimetres from the apex.

2. The following are true above the nasolacrimal duct:

a. it opens into the nose on the anterior part of the lateral 
    wall in the inferior meatus

b. it has a thicker wall than the lacrimal sac

c. it contains a venous plexus along two-third of its length

d. it has an anterior posterior orientation of about 15 

e. it contains valve of Krause at its opening into the 
    nasal cavity
 

Answer
a.T   b.T   c.T   d.T  e.F
The valve of Hasner is found at the distal end
of the nasolacrimal duct before it opens into the nasal cavity.

3. The nasolacrimal duct is covered by the following bones:

a. medial turbinate

b. inferior turbinate

c. maxillary bone

d. lacrimal bone

e. ethmoid bone
 

Answera.F   b.T  c.T  d.T  e.F
The nasolacrimal duct is embedded in the bony 
nasolacrimal canal formed medially by a groove
in the maxillary bone, and laterally by the lacrimal bone (above) and inferior turbinate bone (below).

4. True statements about the turbinates include

a. the inferior turbinate is the largest turbinate

b. the hiatus semiluaris is covered by the middle turbinate

c. the sphenoid sinus drains into the nasal cavity lateral to 
    the superior turbinate

d. the middle turbinate is part of the ethmoid bone

e. the sphenopalatine artery enters the nose at the 
    posterior end of the middle turbinate 

Answer
a.T   b.T  c.T  d.T  e.T

 

5. The following sinuses drain into the infundibulum:

a. posterior ethmoid sinus

b. anterior ethmoid sinus

c. frontal sinus

d. maxillary sinus

e. lacrimal sinus
 

Answer
a.F   b.T  c.T   d.T  e.F
Anterior and not posterior ethmoid sinus drains into the infundibulum. There is no lacrimal sinus.

 

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