Variation in the hypothenar muscles and its impact on ulnar tunnel syndrome

摘要: Compression of the ulnar nerve at Guyon’s canal can be caused not only by tumor-like structures, a fibrotic arch, ganglion, lipoma, aneurysm or thrombosis but also anomalous hypothenar muscles which are reviewed here. For search relevant papers, PubMed and crucial anatomical textbooks were consulted. The abductor digiti minimi is most variable muscle. It possess one to three muscle bellies. Additional heads arise from flexor retinaculum, palmaris longus tendon, pronator quadratus tendon deep fascia palmar side forearm. Our own case an aberrant appearing like connective tissue originating in antebrachial included Hematoxylin eosin staining revealed that macroscopically non-muscle-like contained skeletal tissue. itself resembled other described cases. In addition, accessory with origin long forearm detected. By contrast, opponens mostly lacks variations sometimes missing. our opinion, this due its hidden location. However, few cases additional head lower arm aponeurosis. Furthermore, (fourth) might expressed. These characterized origins insertions on 5th metacarpal bone proximal phalanx. must noted look first glance. Often their extends fascia. This explained phylogenetic fact all intrinsic hand derived masses originated opinion several authors, compression evoked hyper trophied variant overuse as for example carpenters. some rare cases, evoke median compression.