A novel case of ulnar nerve compression neuropathy with co-existing accessory flexor carpi ulnaris and accessory abductor digiti minimi.

There are numerous cases reported of the accessory muscles of the hand and wrist in surgical, cadaveric, and imaging-based studies. Anatomical muscle variations in the flexor compartment of the wrist and forearm can present as a pseudo mass or space-occupying lesion causing external compression on the traversing nerves. Guyon's canal is a compact space with a high potential for nerve entrapment.