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vertredline.GIF (89 bytes)Click on the shaded areas or words for more information. Click on the hand (below) to return to the Hand Kinesiology home page.
Origin: First, lateral head:  Proximal one half of ulnar border of first metacarpal bone. First, medial head:  Radial border of second metacarpal bone. Second, third, & fourth:  Adjacent sides of metacarpal bones in each interspace

Insertion: Into extensor expansion and to base of proximal phalanx via the proximal wing tendons as follows: First:  Radial side of index finger, chiefly to base of proximal phalanx. Second:  Radial side of middle finger. Third:  Ulnar side of middle finger, chiefly into extensor expansion. Fourth:  Ulnar side of ring finger

Innervation: Ulnar, C8. T1

Action: Abducts the index, and ring fingers, and radially and ulnarlly deviates the middle finger from the axial line through the third digit.  Assists in flexion of MCP joints and extension of IP joints of the same fingers.  The first assists in adduction of the thumb.

 

Dorsal Instrinsic | Volar Instrinsic Superficial | Volar Intrinsic Deep | Extrinsic Muscles | Muscle Arrangement | Help | Hand Kinesiology

Lorie Richards and Janice Loudon, University of Kansas Medical Center, School of Allied Health,
Occupational and Physical Therapy Education, October 1997