Perhaps to many a branch of medicine (7)
I believe the answer is:
anatomy
'branch of medicine' is the definition.
'anatomy' can be an answer for 'medicine' (thesaurus). I'm unsure of the 'branch of' bit.
'perhaps to many a' is the wordplay.
'perhaps' indicates anagramming the letters.
'to'+'many'+'a'='tomanya'
'tomanya' anagrammed gives 'ANATOMY'.
Can you help me to learn more?
(Other definitions for anatomy that I've seen before include "Study of body structure" , "Study of the structure of animals" , "mummy?" , "Science of bodily structure" , "Study of bodies" .)