Unusual Co-existence of Biaponeurotic Palmaris Longus and Accessory Abductor Digiti Minimi in Man

The present study describes a rarely reported co-existence of variant muscles in the right upper limb of a male cadaver of 57 years of age, observed during routine anatomical dissection. There was a presence of the biaponeurotic palmaris longus with a central muscle belly in the anterior forearm region which was closely related to the median nerve. In addition to this, an accessory abductor digiti minimi muscle was also reported in the corresponding hypothenar region, traversing the Guyon's canal, passing superficial to the ulnar vessels and nerves. Biaponeurotic palmaris longus and accessory abductor digiti minimi are important structural causes of the entrapment neuropathies of forearm and wrist. Diagnosis of these muscles as a cause of entrapment neuropathies requires the sound knowledge of variant muscles in the forearm and wrist region.