Expansion
PAM, Ptosis Anhidrosis Miosis
Mnemonic
“PAM is horny”, the classic triad plus enophthalmos:
- P - Ptosis, partial, from loss of the superior tarsal (Muller’s) muscle
- A - Anhidrosis, of the face on that side
- M - Miosis, a constricted pupil that dilates poorly in the dark
The level is given by the anhidrosis: whole face and neck suggests a first order (central) lesion; face only suggests second order (preganglionic); no anhidrosis suggests third order (postganglionic), since the sudomotor fibres leave along the external carotid.
The lesions that matter are a Pancoast tumour at the lung apex, carotid dissection (painful, third order), a lateral medullary infarct and neuroblastoma in children. Ptosis here is partial, unlike the complete ptosis of a third nerve palsy.
Expansion
- P - Ptosis, drooping eyelid
- A - Anhidrosis, loss of sweating
- M - Miosis, constricted pupil