a. it has a volume of about 300 ml

b. the nasal bone forms part of the medial orbital wall

c. the palatine forms part of the posterior orbital wall

d. the lateral wall is the thickest aspect of the orbital wall

e. the lesser wing of sphenoid forms part of the lateral wall

answera.F   b.F   c.T   d.T   e.F
The volume is about 30 ml
The nasal bone does not form any parts of the orbital wall
The greater wing and not the lesser wing of the sphenoid forms part of the lateral orbital wall

2. The following forms the lacrimal sac fossa:

a. palatine bone

b. frontal process of maxilla

c. lacrimal bone

d. ethmoid bone

e. frontal bone

answera.F   b.T   c.T   d.F   e.F
The lacrimal sac fossa is formed by the lacrimal bone and the frontal process of the maxilla

3. The following are true about the lacrimal gland:

a. it is covered by the pre-aponeurotic fat

b. it is situated within the zygomatic process of the frontal bone

c. the orbital portion is bigger than the palpebral portion

d. it is responsible for basal tear production

e. botulinum toxin inhibits lacrimal gland tear production

answera.F    b.T   c.T   d.F   e.T
Lacrimal gland has two portion: the larger orbital portion and a smaller palpebral potion.
The pre-aponeurotic fat does not extend to the lateral aspect and therefore during ptosis operation or blepharoplasty, it is important not to mistake lacrimal gland for pre-aponeurotic fat.
It is responsible for reflex tear production
Botulinum toxin inhibits tear production by the lacrimal gland and has been used in the treatment of crocodile tear.
 

a. it is situated between the orbital septum and the levator

b. the trochlear divides the fat into a medial and a lateral pad

c. the lateral pad is larger than the medial pad

d. the medial pad has more fibrous tissue than the lateral pad

e. the medial pad has a yellowish appearance whereas the lateral pad white

answera.T   b.T   c.T   d.T   e.F
The pre-aponeurotic fat pad forms an important anatomic landmark during ptosis operation. The levator is situated beneath the fat pad.
The pad is divided by the trochlear into two pads: the medial and the lateral.
The lateral pad is larger than the medial pad
The lateral pad is yellowish in colour whereas the medial pad is whitish. 
The difference is due to the higher content of fibrous tissue in the medial pad.
 

a. paralysis of the orbicular oculi causes widening of the palpebral fissure

b. procerus is responsible for frowning

c. corrugator is responsible for vertical glabellar wrinkles

d. the frontalis is inserted into the undersurface of the eyebrow

e. the frontalis is deficient laterally

answera.T   b.T   c.T   d.T   e.T
The unopposed action of the levator causes lid retraction in orbicularis oculi paralysis as seen in facial nerve palsy.
Both procerus and corrugator are responsible for frowning and the movement of the medial eyebrows.
The frontalis is deficient laterally and therefore lateral brow ptosis is commoner in the elderly.
 

a. Whitnall's ligament

b. check ligament of eyeball

c. suspensory ligament of eyeball

d. lateral canthal tendon

e. aponeurosis of levator muscle

answera.F   b.T   c.T   d.T   e.T
The Whitnall's ligament inserts 10 mm above the tubercle of Whitnall.
 

a. the supraorbital ridge extends only over the medial one half to two thirds of the superior 
    orbital rim

b. fat pad is found below the eyebrow

c. the frontalis muscle of the forehead supports medial two thirds of the eyebrow

d. the sensory nerves to the forehead travels on the underside of the frontalis

e. the supratrochlear nerve supplies most of the sensation of the forehead

answera.T   b.T   c.T   d.T   e.F
The eyebrow is attached to the underlying bone along the supraorbital ridge by attachments on the underside of the eyebrow fat pad.
Because the supraorbital ridge is only 1/2 to 1/3 of the superior orbital rim and that frontalis only supports the medial two thirds of the eyebrow, lateral ptosis is common.
The sensory nerves to the forehead travels on the underside of the frontalis and pierce the muscle to lie on its anterior surface about 2 cm above the supraorbital ridge.
The supraorbital nerve supplies most of the forehead sensation.

8. The following are true about the nasolacrimal system:

a. the canaliculi are found within the medial canthus along their full lengths

b. the canaliculi are lined by stratified columnar cells

c. the lower canaliculus is shorter than the upper canaliculus

d. the canaliculus can be dilated to three times its size without affecting its 
    integrity

e. sinus of Maier is found in the common canaliculus

answera.F  b.F   c.F   d.T   e.T
The canaliculi are initially surrounded by the pretarsal orbicularis muscles. 
The common canaliculi enters the lacrimal sac within the central fibrous portion of the medial canthus.
The canaliculi are lined by stratified squamous epithelium.
The lower canaliculi are about 10 mm in length and that of the upper canaliculi 8 mm.
The canaliculus can be dilated to 3X its size without its integrity affected.
The common canaliculus histologically is a diverticulum of the lacrimal sac and if dilated is called sinus of Maier.

9. The orbital septum:

a. is attached to the arcus marginalis of the orbital rim

b. is inserted on the levator at a point where the levator muscle becomes 
    aponeurosis

c. is attached to the retractor 4 mm below the inferior tarsal border

d. if attenuated results in fat herniation 

e. limits the spread of cellulitis into the orbit

answera.T   b.F   c.T   d.T   e.T
The orbital septum is continuous with the galea aponeurotica.
It is firmly attached to the arcus marginalis of the orbital rim.
It is inserted on the levator aponeurosis at a point just above where the levator inserts superficially into the orbicularis muscle.
 

a. originates at a point superolateral to the optic foramen

b. is attached to the lesser wing of the sphenoid bone

c. is attached to the circle of Zinn

d. turns from muscle into aponeurosis where superior transverse ligament of 
    Whitnall is found

e. is penetrated by the superior division of the oculomotor nerve at the 
    posterior one-third and anterior two-third junction.

answera.T   b.T  c.F   d.T   e.T
It originates from the lesser wing of the sphenoid bone at a point superolateral to the optic forman.
It is not attached tot he circle of Zinn.
The superior transverse ligament of Whitnall is an important landmark in ptosis operation as it marks the point where the levator muscle turns into aponeurosis.
The superior division of the oculomotor nerve enters the levator muscle at the posterior one-third and anterior two-third junction on the bulbar side.
 
 

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