A Rare Variation of Palmaris Longus Muscle and Flexor Carpi Ulnaris Muscle with Clinical Significance: Case Report

Abstract

Not so many variations of the muscles belonging to the flexor muscle group of the forearm are described in comparison to the tendons of extensor muscle group of the forearm. During routine dissection in the section hall of the Department of Anatomy, Histology and Embryology in Medical University of Sofia we came across a very interesting variation of palmaris longus muscle and the tendons of flexor carpi ulnaris muscle. We observed the division of the tendon of palmaris longus into two wide and flat tendon bellies called lateral and medial. These bellies formed a Y-shaped figure. The lateral tendon belly passed over the upper part of the flexor retinaculum and inserted into the palmar aponeurosis. The medial tendon however ran deeper than the lateral one and the beginning of the palmar aponeurosis and finally reached the flexor retinaculum where it was inserted. We also came across the presence of additional tendon belly belonging to the flexor carpi ulnaris muscle. That additional belly arose from the pisiform like the pisohamate and pisometacarpal ligaments, then ran deeper than usual and finally joined the fourth metacarpal bone.