Abstract
Introduction and objectives : Variations in structures of hand are of clinical and surgical importance. A rare variation of the extensor musculature on the dorsum of hand is extensor digitorum brevis manus (EDBM). Presence of EDBM on the dorsum of hand can be confused for many dorsal hand mass lesions. In the present cadaveric study, an attempt was made to delineate the anatomical morphology and morphometry of EDBM and evaluate its phylogenetic significance and clinical relevance. Methodology: Study was conducted on 78 human hands in the department of anatomy. A longitudinal incision was performed on the dorsum of hand along the axis of middle finger, skin flaps were raised both on radial and ulnar side. A transverse incision was taken at metacarpophalangeal joints from second to fifth fingers. Results: We found EDBM in two incidences. In both the cases it was extending from the distal end of radius, dorsal aspect of wrist joint and from the extensor indicis tendon. Muscle was medial to extensor indicis tendon. Insertion was into the dorsal digital expansion of middle finger. In both the cases it was classified as type III anatomical variety. Conclusion: Appreciation of such variant muscle on the dorsum of the hand is of great significance during clinical and surgical evaluation of mass lesions on the dorsum of hand. Key words: Extensor digitorum brevis manus; dorsum of hand; variations.
Highlights
Introduction and objectivesVariations in structures of hand are of clinical and surgical importance
The first notification of such muscle on the dorsum of hand was by Albinus way back in 1734.2 The term Extensor digitorum brevis manus was first used by Macalister in 1866.3 Less than 300 articles were noted in published literature worldwide in an extensive review conducted by Nakano et al.[4]
The extensor digitorum brevis manus muscle was observed in two hands in one of the cadavers
Summary
During migration of myotomes into the prospective upper limb, there can be various rearrangements giving rise to deviations from perceived normal structures. It’s a variant of finger extensor musculature found in nearly 2 % of general population.1Though it’s a small muscle on the dorsum of the hand, it can be confused for ganglion, tendon sheath cyst, tenosynovitis or exostosis or soft tissue tumor on the dorsum of hand. This structure can be distinguished from others as it is muscular. In type IIc, EDBM tendon inserts with a membranous slip to index finger along with normal insertion of extensor indicis. The current study was taken up to evaluate the occurrence, morphology, classification of EDBM and to review its phylogenetic and clinical significance
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