Ptosis is due to:

Ans. (a) 3rd CN palsy (oculomotor)Ref.:BDC 6th ed. Vol-III/361-62* Ptosis is drooping of eyelid.* Eyelid is comprised of 4 muscles:Muscles, their innervation and functionMuscleCN innervationFunction* LPSIIIOpens the eyelid* Muller's muscleT1 (NOT a CN; sympathetic nerve)Opens eyelid when LPS tired* FrontalisVIICloses the eyelid* Orbicularis oculiVIICloses the eyelid* CN III palsy leads to drooping of eyelid (Ptosis).* CN VII palsy may also cause ptosis.Also Know*All the extraocular muscles are supplied by CN III except lateral rectus and superior oblique.* Lateral rectus supplied by- CN VI* Superior oblique supplied by- CN IVRemember- LR6; So4