Bilateral absence of third and fourth lumbricals: A case report with clinico-evolutionary insight

Lumbricals are wormlike, intrinsic muscle of the hand. During routine dissection of a male cadaver of age approximately ranging between 50 and 55 years, the absence of third and fourth lumbricals on both the palm was observed. First and second lumbricals showed no anatomical variation. Other muscles of hypothenar eminence supplied by deep branch of ulnar nerve which also supplies the third and fourth lumbricals were normal. Lumbricals are principle extensors of interphalangeal joint, and its role in flexion of metacarpophalangeal joint is meager. Variability in the presence of medial two lumbricals has evolutionary correlation and also shows its minimal role in the extension of interphalangeal joint of its respective digits. Henceforth, knowledge of absence of lumbricals is crucial for surgeons while planning for hand surgery.