The presence of anatomical variations of the peripheral nervous system often accounts for unexpected clinical signs and symptoms. We report unusual variations of the lateral and posterior cords of the brachial plexus in a female cadaver. Such variations are attributed to a faulty union of divisions of the brachial plexus during the embryonic period. The median nerve lay medial to the axillary artery (AA) on both sides. On the right, the lateral root of the median nerve crossing the AA and the median nerve in relation to the medial side of the AA was likely the result of a faulty development of the seventh intersegmental artery. We discuss these variations and compare them with the findings of other researchers. Knowledge of such rare variations is clinically important, aiding radiologists, anaesthesiologists and surgeons to avoid inadvertent damage to nerves and the AA during blocks and surgical interventions.
Axillary Artery ; innervation ; Brachial Plexus ; abnormalities ; anatomy & histology ; Cadaver ; Female ; Human Body ; Humans ; Median Nerve ; abnormalities ; anatomy & histology ; Middle Aged

INTRODUCTIONMultiple 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.

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

RESULTSIn 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.

CONCLUSIONMultiple 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.

Cadaver ; Humans ; Malaysia ; Orthopedics ; Tendons ; anatomy & histology ; Tenosynovitis ; diagnosis ; Upper Extremity ; anatomy & histology ; Wrist ; anatomy & histology