First Dorsal Interosseous Muscle Anatomy
- Origin: First metacarpal and the second metacarpal base
- Insertion: Lateral tubercle of the base of the proximal phalanx and secondarily into the dorsal extensor expansion
- Innervation: Cervical roots: C8-T1
- Nerve: Ulnar Nerve(motor branch)
- Function: Index abductor and index MP joint flexion
Diagrams & Photos
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First dorsal interosseous muscle (red arrow). -
First dorsal interosseous muscle between thumb metacarpal (1) and second metacarpal (2). Note distal web and proximal end of first web. Dorsal radial sensory nerve (3) is crossing the muscle.
Key Points
- The first dorsal interosseous is a bipennate muscle (two oblique muscle bellies with a central tendon).
- The first dorsal interosseous muscle can occasionally be involved an intrinsic compartment syndrome.