The accessory heads of the muscles flexor pollicis longus and flexor digitorum profundus (Gantzer muscle) - An anatomical study in Brazilian cadavers.

An important accessory anatomical variation, exclusively human, and related to the muscular ventres of the flexor pollicis longus and flexor digitorum profundus is frequently denominated Gantzer. These variations have close relations with the anterior interosseous nerve (AIN), which provides, for many authors, by direct compression, one of the rare neuropathic syndromes. In this work, thirty-four forearms were dissected from the collections of the Medical School of the Federal University of Minas Gerais and the Department of Basic Sciences of the Federal University of Juiz de Fora, with a prevalence of 50% of the 34 forearms studied for the Gantzer muscle. The muscle relationship was mainly with the flexor pollicis longus muscle and only one occurrence related to the flexor digitorum profundus muscle, described as a rare occurrence of unilateral double formation of Gantzer muscle. Bilaterality was observed in 88.23% of the findings and the dominant innervation for this muscle variation occurred in 82.35% by the anterior interosseous nerve (AIN). The type morphological in all forms found was the fusiform, with 10.5cm of total length and an average of 0.3cm in diameter and all related, as origin, in the medial aspect of the coronoid process of the ulna, next to the origin of the flexor digitorum superficialis muscle. Our work largely reflected the findings of most publications and, considering the controversy of the occurrence of a compressive neuropathy, the data were not sufficient, from a strictly anatomical point of view, to confirm or refute the hypothesis.