The palmar muscles are innervated by either the median or the ulnar nerve, and can be divided as below.
Thenar and Adductor Compartments
- Abductor Pollicis Brevis (APL): Abducts thumb at MCP and CMC jts
- Opponens Pollicis (OP): Opposes thumb at CMC jts
- Flexor Pollicis Brevis (FPB): Flexor thumbs at MCP and CMC jts
- Adductor Pollicis (AP): Adducts thumbs at MCP and CMC jts
Hypothenar Compartment
- Palmaris Brevis (PB) : Tightens the palmar aponeurosis (protective function)
- Abductor Digiti Minimi (ADM) : Abducts little finger at MCP jt
- Flexor Digiti Minimi Brevis (FDMB):Flex little finger at MCP jt
- Opponens Digiti Minimi (ODM):Opposes CMC jt