Upper Lid Retractors include: (A) Muller muscle and superior rectus, (B) Levator palpabrae superioris and superior oblique, (C) Superior oblique and superior rectus, (D) Levator palpabrae superioris & muller muscle
Answer is D. Ans. is 'd' i.e., Levator palpabrae superioris & muller muscle The levator palpebrae superioris is the impoant upper eye lid retractor. Injury or weakness to this muscle leads to ptosis. This muscle is supplied by occulomotor (3') nerve. Deep pa of the elevator muscle is the Muller's muscle, which is sympathetically innvervated. In hypehyroidism, sensitization of the Muller muscle leads to upper eyelid retraction and pseudoproptosis. On the other hand, in Horner's syndrome loss of this muscle action leads to ptosis. The capsulopalpebral fascia assists in lower eyelid retraction and coordinates with eyeball movement. It arises as an extension of the inferior rectus and inses into the lower edge of the lower tarsus and the adjacent orbital septum.