Clinical Assessment of Absence of Palmaris Longus Muscle and its Association with Gender, Body Sides, Handedness and Other Neighboring Anomalies in a Population of Central India

Abstract

The palmaris longus (PL) is a vestigial or degenerating superficial muscle in the anterior compartment of forearm. It is variable in its structure, attachments and presence or absence in different individuals in various populations and even in one population among individuals. It is well known that individuals may have unilateral or bilateral absence of PL. The aims of this study were to determine the incidence of absence of PL and its association with gender, body sides, handedness and other neighboring anomalies like the absence of flexor digitorum superficialis (FDS) muscle to little finger, the incomplete superficial palmar arch (SPA) etc. in a population of central India; and to correlate the same with the other related studies. We examined 400 Caucasian subjects (200males and 200 females of a population of central India) aged 18–55 years. Total 65 (16.25%) subjects had overall absence of PL, out of which 25 (6.25%) presented bilateral absence and 40 (10%) presented unilateral absence so statistically unilateral absence was little more common than bilateral absence. Overall absence and unilateral absence of PL were little more common in males (M:8.5%,17:7.75% and M:5.75%,17:4.25% respectively) whereas bilateral absence was little more common in females (17:3.5%,M:2.75) however these associations with gender were not statistically significant. In unilateral PL absence, the right and the left sides were more or less equally affected (RT: 5.25%, LT: 4.75%) and no statistical significance was evident for this association with body sides. Out of 65 subjects with absence of PL only 5 were left handed and rest right handed so this association with handedness was also statistically insignificant. No correlation was evident between PL absence and other neighboring anomalies like absence of FDS to little finger, incomplete SPA etc. So the present study concluded with (i) The unilateral absence is statistically little more common than the bilateral absence (ii) There is no statistical association between the PL absence and gender, body sides, handedness and other neighboring anomalies like absence of FDS to little finger, incomplete SPA etc. in a population of central India.