0350 ch 27-Tab 10/12/04 5:12 PM Page 4 4 Therapeutic Exercise: Moving Toward Function TABLE 27-4 Muscles Functioning Primarily at the Hand SPINAL PERIPHERAL MUSCLE ORIGIN INSERTION ACTION LEVEL NERVE Extensor Common extensor Middle and base of Extends MCP joints C6–C8 Radial digitorum tendon of lateral distal phalanx and assists extension epicondyle of digits 2–5 of IP joints Extensor indicis Posterior ulna Extensor expansion Extends MCP joint C7–C8 Radial of index finger and assists IP joint extension Extensor digiti Common extensor Extensor expansion Extends MCP joint C7–C8 Radial minimi tendon of fifth digit and assists with IP joint extension Palmaris longus Common flexor Flexor retinaculum, Tenses palmar fascia C7–C8 Median (PL) tendon palmar aponeurosis Flexor digitorum Common flexor Middle phalanges of Flexes proximal IP C7–C8 Median superficialis tendon; coronoid digits 2–5 joints, assists MCP (FDS) process; radius joint and wrist flexion Flexor digitorum Anteromedial ulna Bases of distal Flexes DIP joints; profundus phalanges digits assists flexion of IP (FDP) 2–5 and MCP joints Flexor digiti minimi Hook of hamate Proximal phalanx MCP flexion of C8 Ulnar of fifth digit fifth finger Opponens digiti Hook of hamate Length of fifth MC Opposes CMC of C8–T1 Ulnar minimi fifth finger Dorsal interossei Metacarpal bones Radial and ulnar Digit abduction and C8–T1 Ulnar sides of fingers assists flexion and extension Palmar interossei Metacarpal bones Ulnar and radial Adduction of fingers C8–T1 Ulnar sides of fingers IP, interphalangeal; MCP, metacarpophalangeal. Hall & Brody: Therapeutic Exercise: Moving Toward Function, 2nd Edition © 2005, Lippincott Williams and Wilkins.