Can External strabismus and ptosis be caused by damage to the oculomotor nerve?

Yes, both external strabismus and ptosis can be caused by damage to the oculomotor nerve. Damage to the oculomotor nerve can disrupt the control of the levator palpebrae superioris muscle responsible for elevating the eyelid, leading to ptosis, and disruption of lateral rectus, superior rectus, and inferior rectus muscles, responsible for extraocular movements, can lead to external strabismus.