The lower half of the forearm is so largely tendinous that musculocutaneous flaps are unsuitable; by the time the tendons are cut short there is little tissue left but skin, superficial and deep fascia, and a few muscular fibres.

Amputation should be performed as low down as one can so as to save as much as possible. Artificial appliances, so useful in the lower extremity, are, practically, of little value in the upper. The preservation of the power of pronation and supi- nation is to be accomplished when the condition permits. The pronator radii teres has its insertion in the middle of the radius and if the division of the bone is below that point rotary movements will be preserved.

The surgeon should be acquainted with the position of the main arteries and nerves. Four arteries will require ligation: the radial, ulnar, volar (anterior), and dorsal (posterior) interosseous. Their position as well as that of the nerves will vary accordingly to the site of the amputation. The median and ulnar are the only nerves that require shortening.

Amputation Through The Upper Third

The radial artery is to be looked for near the surface under the deep fascia, just beneath the edge of the brachioradialis muscle.

The ulnar artery lies between the superficial and deep flexor muscles somewhat toward the ulnar side of the median line.

The volar interosseous artery lies in front of the interosseous membrane.

The dorsal interosseous lies between the superficial and deep muscles on the back of the forearm more toward the ulnar side.

The median nerve is to be sought in the middle line of the forearm below the superficial flexor muscles.

The ulnar nerve lies to the ulnar side of the ulnar artery on a level with it and beneath the flexor carpi ulnaris muscle.

Amputation Through The Middle Third

The radial artery lies beneath the deep fascia in front of the radius along the inner edge of the brachioradialis.

Fig. 33 7.   Amputation about the middle of the forearm.

Fig. 33 7. - Amputation about the middle of the forearm.

The ulnar artery here becomes more superficial and lies beneath the radial edge of the flexor carpi ulnaris muscle.

The volar interosseous is found lying on the anterior surface of the interosseous membrane or the thin edge of the flexor profundus.

The dorsal interosseous lies posterior to the membrane between the superficial and deep extensor muscles.

The median nerve is directly in the midline beneath the flexor sublimis and above the flexor profundus digiterum.

The ulnar nerve lies to the radial side of the ulna, to the ulnar side of the ulnar artery, and under the flexor carpi ulnaris muscle (Fig. 337).

Amputation Through The Lower Third

The radial artery lies beneath the deep fascia between the flexor carpi radialis and brachioradialis.

The ulnar artery lies to the ulnar side under the deep fascia and at the edge of the flexor carpi ulnaris muscle.

The volar and dorsal interosseous arteries are too small to require ligation.

The median nerve lies beneath the palmaris longus muscle. At the wrist it lies beneath the interval between it and the flexor carpi radialis.

The ulnar nerve is superficial along the edge of the flexor carpi ulnaris and accompanies the ulnar artery along its medial (ulnar) side.