Muscle Test Group: Extensor digitorum communis, extensor indicis proprius, and extensor digiti minimi.
• Extensor digiti minimi is tested in a muscle group with extensor digitorum communis and extensor indicis proprius.
• Extends the small finger.
• Extrinsic muscle.
• In the fifth extensor compartment of the wrist.
Tendon Transfers: Is useful for tendon transfer procedures because it provides redundant function.
Extensor digiti minimi (EDM) is examined and tested with extensor digitorum communis (EDC) and extensor indicis proprius. EDM runs parallel with EDC on the ulnar/lateral side and inserts into the extensor expansion of the little finger with EDC. Refer to extensor digitorum communis for examination.
Muscle Function: Extends the metacarpo-phalangeal joint of the little finger. In conjunction with the lumbricalis and interosseous, extends the interphalangeal joints of the little finger. Assists in abduct of the little finger.
• Roots: C6, C7, C8.
• Nerve: Radial nerve, posterior interosseous nerve.
• Innervation Route: C6, C7, C8 → radial nerve → posterior interosseous nerve → extensor digiti minimi.
Origin: Common extensor tendon from the lateral epicondyle of the humerus and deep antebrachial fascia.
Insertion: Into the extensor expansion of the little finger with the extensor digitorum communis tendon.