(op-ō'nenz dij'i-tī mi'ni-mī mŭs'ĕl) Origin, hamulus of the hamate bone and transverse carpal ligament; insertion, shaft of fifth metacarpal; action, "cups" palm, drawing ulnar side of hand toward center of palm; nerve supply, ulnar. Synonym(s): musculus opponens digiti minimi [TA] .