FUNCTIONAL-ANATOMY OF THE EXTENSOR TENDONS OF THE DIGITS

The extrinsic extensor muscles of the forearm have relatively long fib ers, small pennation angles, and small, physiologic cross-sectional ar eas. From an architectural standpoint, they are designed more optimall y for excursion and velocity and less optimally for force generation. Tendon multiplicity and variations are more common on the ulnar side t han on the radial side, with the most common pattern consisting of a s ingle EIP tendon, a single EDC index, a single EDC long, a double EDC ring, an absent EDC small, and a double EDQ. Anomalous extensor muscle s indicis the extensor medii proprius, extensor indicis et medii commu nis and extensor medii et annularis communis, extensor digitorum brevi s manus, and extensor carpi radialis intermedius. Juncturae tendinum i nclude three general types: type 1 is a thin filamentous correction, t ype 2 is thicker and better defined, and type 3 is a thick tendon-like slip between extensors.