Publication

Abstract : Introduction and Aims: The movements of the thumb are carried out by three muscles originating from the forearm viz., two extensors (a longus and a brevis) and an abductor. Anatomical variation has been observed in one out of every six cadavers. Among the muscles of the thumb the abductor is commonly known to show such variations. Aim of this report is to present the frequency of variations in local population. Materials and Methods: The data for the present study was collected by dissection of fifty hands (30 adult and 20fetal).Tendon slips of each of the three muscles were counted and their width was measured with a calliper. Observations: A single tendon slip of extensor pollicis longus was found in 43 (86%) hands, and in seven (14%) the tendon slip was duplicated. The extensor pollicis brevis tendon was found to have a single slip in 47 (94%) hands and in three (6%) the tendon slip was duplicated. The abductor pollicis longus tendon (APL) had a single slip in 38(76%) hands, double and triple together in 11(22%). The APL was absent in one (2%) hand. In one adult male the APL had three slips of origin; anterior slip formed a fusiform belly attached to the base of the proximal phalanx. On the left side of the same cadaver the muscle had two slips, the anterior slip divided into two, one of these ended in a fusiform belly within the thenar eminence. Conclusions: Knowledge of anatomical variations of the tendons of the thumb is essential during the surgical repair and in cases where tendon transfer is required. Multiple tendons are known to cause conditions like de Queverain's syndrome.