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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: Flexor retinaculum, tubercle of trapezium bone, and tubercle of scaphoid bone.

Insertion: Base of proximal phalanx of thumb, radial side, and extensor expansion

Innervation: Median, C6, 7, 8, T1

Action: Abducts the CMC and MCP joints of the thumb in a ventral direction perpendicular to the plane of the palm. May extend the IP joint of the thumb. Assists in opposition and may assist in flexion and medial rotation of the MCP joint.

Volar Intinsic Superficial | Volar Instrinsic Deep | Dorsal Intrinsic Muscles | 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