Ulnar artery palmar to palmaris brevis: cadaveric study and three case reports.

Three cases in which the ulnar artery was palmar to the palmaris brevis muscle at the level of the wrist are described and the results of a cadaveric study are presented. The anomaly was confined to the level of Guyon's canal with a normal position of the artery proximally in the forearm and distally in the palm. In spite of its superficial location, the artery was patent in all patients and no symptoms referable to the ulnar artery were present. The ulnar nerve was found dorsal to the palmaris brevis in Guyon's canal in all three patients. An accessory muscle was found in one patient, but no other anatomic anomalies were seen. A cadaveric study of 43 limbs revealed a similar anomaly of the ulnar artery in 1 cadaver. In the presence of this anomaly the ulnar artery may be at increased risk during surgical exploration of Guyon's canal. Exposure of the artery in the forearm prior to exploration of Guyon's canal is recommended.