Horner's Syndrome pic

Horner's Syndrome is a syndrome caused by a lesion in the sympathetic nervous system, especially the cervical chain or central pathways, and characterized by drooping upper eyelid(ptosis), pupillary contraction(miosis), absence of sweating(anhydrosis), and receding eyeball


Loss of sympathetic nervous system input to (in this case) right eye.

Note that right pupil is smaller than left. Also that right eyelid covers a greater portion of eye than on left
(known as ptosis). The etiology in this case was due to tumor infiltrating the sympathetic chain.