Table 1.

Anomalies of the Ulnar Nerve Within and Around the Guyon Canal.

Ulnar Nerve Anomalies
Branching pattern Bifurcation of the ulnar nerve proximal to the canal Trifurcation of the ulnar nerve proximal and within the canal Bifurcation of the ulnar nerve that encircles the pisiform Aberrant branches arising from the ulnar nerve proximal to the canal
Deep motor branch Aberrant origin of motor branch of the ulnar nerve Nerves to hypothenar muscles ranges from 1 to 4 branches Bifid deep motor branch of the ulnar nerve with or without neural loop
Superficial sensory branch Aberrant origin of superficial branch of the ulnar nerve Single, bifurcated, or trifurcated sensory branch(es)
Anomalous course The ulnar nerve inside the carpal tunnel
Communication with median nerve Martin-Gruber anastomosis Marinacci communications Riche-Cannieu anastomosis Berrettini anastomosis and ramus communicans
Dorsal cutaneous branch Kaplan accessory branch