Morphologie et morphométrie du chef ulnaire du muscle Pronator Teres et ses relations avec une compression du nerf médian à l’avant-bras proximal

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IntroductionThe pronator syndrome is a rare compression neuropathy of the median nerve. Ulnar head of the pronator teres muscle may cause compression at proximal forearm. HypothesisDetailed morphologic and morphometric studies on the anatomy of the ulnar head of pronator teres is scarce. Material and methodsWe dissected 112 forearms of fresh cadavers. We evaluated the morphology and morphometry of the ulnar head of pronator teres muscle. ResultsThe average ulnar head width was 16.31±8.2mm. The median nerve passed anterior to the ulnar head at a distance of 50.36±10.7mm from the interepicondylar line. We classified the morphology of the ulnar head into 5 types. In type 1, the ulnar head was fibromuscular in 60 forearms (53.6%). In type 2, it was muscular in 23 forearms (20.5%). In type 3, it was just a fibrotic band in 18 forearms (16.1%). In type 4, it was absent in 9 forearms (8%). In type 5, the ulnar head had two arches in 2 forearms (1.8%). In 80 forearms (71.5%: types 1, 3, and 5), the ulnar head was either fibromuscular or a fibrotic band. DiscussionAlthough the pronator syndrome is a rare compression syndrome, the ulnar head of pronator teres is reported as the major cause of entrapment in majority of the cases. The location of the compression of the median nerve in relation to the ulnar head of pronator teres muscle and the morphology of the ulnar head is important for open or minimally invasive surgical treatment. Type of studySectional study. Level of evidenceBasic science study.