Topographical relations between the Gantzer's muscle and neurovascular structures.

PURPOSE: Gantzer's muscle (GM) is an additional muscle in the forearm, which develops as an accessory head of the flexor pollicis longus or the flexor digitorum profundus. The study aimed to determine the topography of the GM and to define the topographical relationship between the GM and the neurovascular structures surrounding it.

METHODS: After confirming the presence of GM, its topography and the neurovascular structures were analyzed to determine the correlation between them in 73 upper limbs.

RESULTS: The incidence of GM was 47.95% (35/73) and the average insertion point of GM was identified at 49.33 ± 7.47‰ (119.82 ± 20.80 mm) on the reference line between the medial epicondyle and the pisiform bone. And the branching points of the median nerve and the ulnar artery were located 19.91 ± 11.23‰ (52.21 ± 24.67 mm), 17.45 ± 8.39‰ (42.53 ± 20.54 mm) on the reference line, respectively. The presence of GM had no significant correlation with the position of the nerve branches. On the other hand, the branching point of the ulnar artery was distally located in the cases with the presence of the GM (17.35 ± 8.65 vs 19.42 ± 10.87, p = 0.031). There was a significant positive correlation between the point of arterial bifurcation and the length of the GM (r = 0.407, p = 0.015).

CONCLUSIONS: This study suggested that the GM has a topographical relation with the arterial structures, perhaps for embryological reasons.