Abductor pollicis brevis APB Thenar Group Attachments Proximal

Abductor pollicis brevis (APB)

Thenar Group Attachments: Proximal: Tubercles of scaphoid + trapezium + flexor retinaculum Distal: Base of PROXIMAL phalanx of thumb (lateral side) Action: ABduct CM jt of thumb PERIPHERAL NERVE + spinal cord level of origin: Median nerve: C 6, 7, 8, T 1 Spinal Segments: C 6, 7, 8, T 1

Flexor pollicis brevis (FPB)

Thenar Group Attachments: Proximal: Tubercle of trapezium + flexor retinaculum Distal: Base of PROXIMAL phalanx of thumb (lateral side) Action: Flex MP + CM jts of thumb PERIPHERAL NERVE + spinal cord level of origin: Median nerve: C 6, 7, 8, T 1 Spinal Segments: C 6, 7, 8, T 1

Opponens pollicis

Thenar Group Attachments: Proximal: Tubercle of trapezium + flexor retinaculum Distal: Body of 1 st metacarpal (lateral side) Action: Opposes CM jt of thumb (3 of 4 opposition movements = AB, flex, + MR) PERIPHERAL NERVE + spinal cord level of origin: Median nerve: C 6, 7, 8, T 1 Spinal Segments: C 6, 7, 8, T 1

Adductor pollicis: Oblique and transverse heads

Thenar Group Attachments: Proximal: Oblique Head: Capitate + base of metacarpals 2 + 3 Transverse Head: 3 rd metacarpal Distal: Base of PROXIMAL phalanx of thumb (medial side) Action: ADduct CM jt of thumb PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1

Abductor Digiti Minimi (ADM)

Hypothenar Group Attachments: Proximal: Pisiform + tendon of FCU Distal: Base of PROXIMAL phalanx of digit 5 Action: ABduct MP jt of 5, assist in flex MP of 5 PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1

Flexor digiti minimi (brevis)

Hypothenar Group Attachments: Proximal: Hook of hamate + flexor retinaculum Distal: Base of PROXIMAL phalanx of digit 5 Action: Flex MP jt of 5 PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1

Opponens digiti minimi

Hypothenar Group Attachments: Proximal: Hook of hamate + flexor retinaculum Distal: Body of metacarpal 5 Action: Oppose CM jt of 5 (AD, flex, + LR) PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1

Lumbricals (4)

Palmar Group Attachments: Proximal: Tendons of FDP (on radial side) Distal: Dorsal apparatus on radial side of 2, 3, 4, 5 Action: Extend IP jts 2 -5, flex MP jts 2 -5 PERIPHERAL NERVE + spinal cord level of origin: Median n. to I, II; Ulnar n. to III, IV Spinal Segments: C 8, T 1

Palmar interossei (PAD) unipennate form

Palmar Group Attachments: Proximal: Metacarpals 2, 4, 5 on palmar surface Distal: Dorsal apparatus on digits 2, 4, 5 Action: ADduct + flex MP + extend IP jts of 2, 4, 5 PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1

Dorsal interossei (DAB) bipennate form

Palmar Group Attachments: Proximal: Adjacent sides of two metacarpals Distal: Dorsal apparatus on digits 2, 3, 4 Action: ABduct MP jt 2, 4. RD + UD MP jt 3. Flex MP jt 2, 3, 4. Extend IP jts 2, 3, 4 PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1

Palmaris brevis

Palmar Group Attachments: Proximal: Flexor retinaculum + palmar aponeurosis Distal: Skin on ulnar side of palm Action: Wrinkle palmar fascia – for grip PERIPHERAL NERVE + spinal cord level of origin: Ulnar nerve: C 8, T 1 Spinal Segments: C 8, T 1