First Dorsal Interosseous


Origin: the adjacent surfaces of the thumb and index metacarpals

Insertion: the radial base of the index proximal phalanx and the index radial digital extensor mechanism

Function: flexes, radially deviates (abducts) and pronates the index MCP joint and radially adducts the thumb basal joint along with other muscles which radially adduct the basal joint. Also (weakly) extends the index PIP and DIP joints

Nerve: Motor Branch of Ulnar Nerve

Artery: deep palmar arch

Interossei - all

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