Palmaris Inversus Muscle: A Case Report With Clinical and Surgical Discussions

Abstract

Background:The palmaris longus muscle is a slender fusiform muscle. It is especially prone to vary in comparison to other muscles in the upper limb and it is considered to be a vestigial structure. It is the most variable muscle in the human body, although its reverted state is barely discussed. The palmaris longus inversion can cause compression on neurovascular bundles, specially the median nerve on the carpal tunnel and the ulnar nerve on the Guyon canal.

Hypertrophic reversed palmaris longus muscle: a cadaveric finding

“…Despite that, it usually originates from the medial epicondyle of the humerus as a fusiform muscle belly. Then, at the middle third of the forearm it turns into a long tendon that inserts itself into the palmar aponeurosis [7,11,20,21].…”

“…It acts as a weak wrist flexor and it puts tension into the palmar aponeurosis, although there is a debate regarding its actual function and significance [1,11,13,20,21]. It is innervated by the median nerve (MN) [11,21].…”

“…Nerve entrapment and effort-related compartment syndrome has been associated with the presence of a reversed PLM (RPLM) [17,20].…”