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The dorsal interosseous muscles are paired intrinsic muscles of the hand situated between the metacarpals (see Image. Dorsal Interossei of the Hand). This group consists of 4 muscles responsible for finger abduction. These muscles also contribute to flexion at the metacarpophalangeal (MCP) joints and extension at the interphalangeal joints. All interossei receive innervation from the deep branch of the ulnar nerve. Injury to this nerve can significantly impair intrinsic hand function, particularly finger abduction and adduction, which depend primarily on the interossei.[1] Understanding the anatomy and physiology of the dorsal interosseous muscles aids in diagnosing ulnar nerve injuries and evaluating hand dysfunction. Precise knowledge of these muscles supports surgical planning for procedures involving the metacarpals, tendon repairs, and nerve decompression. Palpation and functional testing of the interossei provide valuable insight during clinical examinations, particularly in cases of trauma or neuropathy. Mastery of interosseous muscle mechanics enhances outcomes in reconstructive and rehabilitative hand surgery.