Aberrant tendinous variation of the pronator quadratus muscle: A case report

A 46-year-old right-hand dominant female underwent a distal radius corrective osteotomy for fracture malunion. A standard flexor carpi radialis incision to the volar wrist was used. In the deep dissection, the fibers were oriented in a transverse fashion consistent with the typical appearance of pronator quadratus (PQ) fibers. However, the muscle belly of the PQ was not visualized. After further dissection, we concluded that this tendinous structure was an aberrant anatomic variation of the PQ muscle. Although anatomical variation of other tendons and muscles of the forearm, hand and wrist are common, this is the first case report describing an aberrant tendinous pronator quadratus. Although aberrant tendons are usually not pathological, these variations may contribute to specific medical conditions. Many forearm tendons are commonly used as donor tendons for reconstructive surgeries in the hand, wrist and fingers. Knowledge of anomalous tendons of the hand and forearm is clinically relevant and may prevent uncertainty on the surgical approach.