Extensor of fingers

Extensor of fingers, m. Extensor digitorum, has a spindle-shaped abdomen, and in the direction of the muscular bundles it is bipedular. The muscle lies directly under the skin, closer to the lateral margin of the rear surface of the forearm, and borders on the ulnar side with m. Extensor carpi ulnaris and m. Extensor digiti minimi, and with radiation - with mm. Extensores carpi radiales longus et brevis.

The muscle begins from the lateral epicondyle of the humerus, the joint capsule of the elbow joint and the fascia of the forearm. At the middle of its length the muscular abdomen passes into 4 tendons which, passing under the extensor retainer, are surrounded with the tendon of the extensor of the index finger with the vagina of the extensor tendons of the fingers and forefinger, vagina tendinum mm. Extensoris digitorum and extensoris indicis, reaching approximately the middle of the metacarpal bones.

Going to the brush, the tendons are interconnected by unstable sub-interspecific joints, connexus intertendinei, and at the base of the proximal phalange, from the index finger to the little finger, each tendon ends with a sinewy sprain that fuses with the joint capsule of the metacarpophalangeal joint. Tendon extensions are divided into 3 legs, of which the lateral attach to the base of the distal phalanx, and the middle to the base of the middle phalanx.

Function: extends fingers, taking part also in extension of the hand in the wrist joint.

Innervation: n. Radialis (CVI-CVIII).

Blood supply: a. Interossea posterior.