Surgical implications of variations in hand collateral circulation: anatomy revisited.

OBJECTIVES: One of the risks associated with harvesting the radial artery is hand ischemia. Accordingly, this study investigated the variations of the hand collateral circulation. METHODS: Fifty hands of cadavers were examined. Variations of the palmar arches were recorded. A classic superficial palmar arch was defined as direct continuity between the ulnar artery and the superficial palmar branch of the radial artery. A classic complete deep palmar arch was defined as direct continuity between the radial artery and the deep branch of the ulnar artery. RESULTS: A classic superficial palmar arch was found in 10% (5/50) of hands, and a classic complete deep palmar arch was found in 90% (45/50) of hands. The superficial palmar branch of the ulnar artery supplied blood to all fingers in 66% (33/50) of hands. Although the superficial palmar branch of the ulnar artery was continuous with the radial artery in only 34% (17/50) of hands (including the classic type of superficial palmar arch), every hand had at least one major branch connecting the radial and ulnar arteries. CONCLUSIONS: Variations in the terminations of the radial and ulnar arteries are common. Although the classic type of superficial palmar arch occurs relatively infrequently, there is always a significant anastomosis between the radial and the ulnar artery in the hand. This anatomic study confirms the presence of a collateral supply in the hand. In the absence of vascular disease, harvesting the radial artery should be regarded as a safe procedure.

Anatomy of the karate chop.

A reticular shell of tendon-like fibers lines the teguments of the hypothenar space. This fibrous shell, together with the exceptionally thick skin and the arrangements of the fat tissues, gives the "heel of the hand" a remarkable resistance to pressure.

[The role of the retinaculum extensorum in the stability of the wrist (author's transl)]. / Le rôle du ligament annulaire postérieur du carpe, dans la stabilité du poignet.

The carpus is attached to the radius mainly by two radiocarpal ligaments, anterior and posterior. These ligaments are not symmetrical and cannot oppose on the ulnar side the action of the longitudinal force of the extrinsic muscles of the fingers. This force is directed by the volar and ulnar inclination of the radial articular surface. This force initiates a movement of supination of the carpus and of anterior subluxation. The main fibrous structure which may oppose this force is the posterior annular ligament (retinaculum extensorum).

The proximal end of the palmar aponeurosis.

The proximal end of the palmar aponeurosis receives two important contingents of fibres from the flexor carpi ulnaris tendon. The superficial contingent blends with the fibres of palmaris longus; the deep contingent runs on the surface of the pisohamate ligament and connects the flexor retinaculum to the palmar aponeurosis. In congenital absences of the palmaris longus, flexor carpi ulnaris completely takes over as the longitudinal tensor of the palmar aponeurosis.

On the form and function of the abductor pollicis brevis muscle.

The abductor pollicis brevis muscle acts in conjunction with the palmaris longus and the abductor pollicis longus to abduct the first metacarpal in the sagittal plane. Segments of the abductor pollicis brevis which arise from the tendons of the palmaris longus and/or the abductor pollicis longus and are inserted into the extensor expansion are the lumbricals of the thumb. The lateral border of the abductor pollicis brevis presents an important muscular (in four cases out of ten neurovascular) hilum. The tendinous slip to the abductor pollicis brevis from the palmaris longus presents near its origin an orifice which the palmar branch of the median nerve traverses to become superficial.

Palmaris longus, anteductor of the thumb.

Palmaris longus contributes to the anteposition and pronation of the thumb under circumstances. It is however restricted by its medial tendon which runs into the palmar aponeurosis. The diversion of this tendon and the mobilisation of the muscular head of the abductor pollicis brevis arising from its lateral tendon will substantially accentuate the rôle of palmaris longus as a muscle of the thumb.