Multiple variations of the tendons of the anatomical snuffbox

Abstract

Introduction: Multiple tendons of the abductor pollicis longus (APL) in the anatomical snuffbox of the wrist can lead to the development of de Quervain's syndrome, which is caused by stenosing tenosynovitis. A cadaveric study was performed to establish the variations present in the tendons of the anatomical snuffbox in a Malaysian population, in the hope that this knowledge would aid clinical investigation and surgical treatment of de Quervain's tenosynovitis.

Methods: Routine dissection of ten upper limbs was performed to determine the variations in the tendons of the anatomical snuffbox of the wrist.

Results: In all the dissected upper limbs, the APL tendon of the first extensor compartment was found to have several (3-14) tendon slips. The insertion of the APL tendon slips in all upper limbs were at the base of the first metacarpal bone, trapezium and fascia of the opponens pollicis muscle; however, in seven specimens, they were also found to be attached to the fleshy belly of the abductor pollicis brevis muscle. In two specimens, double tendons of the extensor pollicis longus located in the third extensor compartment were inserted into the capsule of the proximal interphalangeal joints before being joined to the extensor expansion. In two other specimens, the first extensor compartment had two osseofibrous tunnels divided by a septum that separated the APL tendon from the extensor pollicis brevis tendon.

Conclusion: Multiple variations were found in the anatomical snuffbox region of the dissected upper limbs. Knowledge of these variations would be useful in interventional radiology and orthopaedic surgery.

Fig. 1

Schematic diagram shows the extensor compartments (1–6) of the dorsum of the hand and their contents.

Fig. 2

Photograph of the left upper limb of specimen 10 shows the APL with 14 tendon slips. Some tendons of the extensor and flexor compartments are also seen. APL: abductor pollicis longus; ECRB: extensor carpi radialis brevis; ECRL: extensor carpi radial is longus; ED: extensor digitorum; EI: extensor indicis; EPB: extensor pollicis brevis; EPL: extensor pollicis longus; FCR: f lexor carpi radialis; FD: f lexor digitorum

Fig. 3

Photograph of the right upper limb of specimen 1 shows the insertion of the APL tendon into the fleshy belly of the APB. Other tendinous slips of the APL show attachment to the fascia of the opponens pollicis muscle. APL: abductor pollicis longus; APB: abductor pollicis brevis; EPB: extensor pollicis brevis; EPL: extensor pollicis longus

Fig. 4

Photograph of the right upper limb of specimen 10 shows the EPL with two tendons. The anatomical snuffbox, together with the cephalic vein, is also shown. EPB: extensor pollicis brevis; EPL: extensor pollicis longus

Fig. 5

Photograph of the left upper limb of specimen 5 shows the tendons of the APL and EPB within separate tunnels in the first extensor compartment. Also shown are the radial artery and cephalic vein in the anatomical snuffbox. APL: abductor pollicis longus; EPB: extensor pollicis brevis