[Ulnar nerve compression in the area of the wrist].

Clinical investigation precisely determines the localization of ulnar nerve entrapment in Guyon's canal. The cause of compression can be due to internal (tumor, distal fibrous arch or proximal ligament arcade, nerve or muscle anomalies) or external influences (ulnar neuropathy of cyclists, thrombosis of ulnar artery by hypothenar hammer syndrome, fractures of pisiform or hook of hamate). Treatment involves splitting the roof of Guyon's canal, the ligaments or muscle anomalies, and excision of a tumor.