They connect to scapulae (6)
I believe the answer is:
humeri
'they connect to scapulae' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for humeri that I've seen before include "Bones in upper arm from shoulder to elbow" , "Bones form shoulder to elbow" , "Upper-arm bones" , "Bones from shoulder to elbow, in Latin plural" , "Components of arms" .)