Revisiting the Morphological Variations in Lumbricals of Hand

Abstract

Introduction: The lumbrical muscles are unique in their functions in being only intrinsic muscles which bridges between the palmar and dorsal surface. This unique property endows them in performing fast, alternating movements and fine tuning digit motion. The aim of this study was to evaluate the anatomical variations in the morphology and architecture of lumbricals and to discuss its clinical implications. Subjects and Methods: This study was conducted on 74 disarticulated upper limbs during routine dissection of cadavers in the Department of Anatomy of MVJMC & RH. The dissection was carried out based on the steps as per the Cunningham’s manual. Results: Variations in lumbricals were observed in 12 specimens (8 in right side & 4 in left side). The variation encountered were the proximal origin of lumbricals in 4 specimens (5.41%), Split insertion in one specimen (1.35%), bipennate second lumbrical in two specimens (2.70%), accessory belly of first lumbrical in 4 specimens (5.41%) and hypertrophied lumbrical in one specimen (1.35%). Conclusion: Variations of the lumbrical can present with wide range of clinical presentations like compression of neurovascular structures as in hypertrophy, carpal tunnel syndrome as in proximal origin and accessory belly of lumbrical.