Optho 6

Question 1

a. Anterior and posterior lamellae

Answer 1

the anterior lamella is made up of the skin, orbicularis muscle and levator aponeurosis, the posterior lamella is made up of the tarsal plate, Muller’s muscle and palpebral conjunctiva.

Question 2

Lid margin

Answer 2

contains the eyelash follicles in the anterior lamella, the grey line is the area where the anterior and posterior lamellae meet, and the meibomian gland orifices are contained in the posterior lamella.

Question 3

c. Orbital septum, relationship to eyelid/ orbit

Answer 3

the orbital septum is a connective tissue membrane the extends from the orbital rim to the levator aponeorosis superiorly, and to the lower lid retractors inferiorly. It is inelastic, and functions to hold back the orbital fat into the retro-orbital space.

Question 4

Eyebrow

Answer 4

an area of transition from the eyelid to the forehead that is often marked by several rows of cilia. Ideally it is located at the prominence of the superior orbital rim, but frequently drops with age due to loss of elasticity. It functions to prevent sweat from the forehead from entering the eye. It is also important in non-verbal communications and frequently the recipient of cosmetic attention.

Question 5

Levator aponeurosis

Answer 5

the fibrous connective tissue that extends from the levator to the anterior tarsal plate and overlying eyelid skin. Its insertion is responsible for the upper eyelid crease.

Question 6

f. Sensory supply

Answer 6

V1 and V2

Question 7

g. Motor supply

Answer 7

cranial nerve III (levator palpebrae), cranial nerve VII (orbicularis oculi), and upper eye lid sympathetic innervations (Muller’s muscle).

Question 8

i. Blepharoptosis

Answer 8

an abnormally low position of the upper eyelid, it may be classified as neurogenic, myogenic, aponeurotic or mechanical.

Neurogenic refers to a defect in the motor innervation of the upper eyelid, most often due to either a third nerve palsy or Horner’s syndrome. Myogenic refers to conditions in which the muscle cannot function properly such as myasthenia gravis or myotonic dystrophy.aponeurotic is the most commons and refers to stretching or dehiscence of the levator aponeurosis due to either aging or surgical trauma. Mechanical ptosis is the result of impaired mobility of the upper lid due to large eyelid lesions (neurofibroma, hemangioma), scarring, edema or anterior orbital lesions.

Question 9

i. Chalazion

Answer 9

chronic lipogranulomatous inflammatory lesion caused by blockage of meibomian gland orifices and stagnation of secretions.