An unusual case of an accessory head of the brachioradialis muscle: case report and literature review

The two-headed brachioradialis (BR) muscle represents a rare anatomical variation. The present study aims to describe this variant and provide detailed morphometric documentation. The study was conducted during routine anatomical dissection of a formalin-fixed 92-year-old male cadaver in whom a two-headed BR muscle was identified in the right upper limb. Detailed dissection was performed, and morphometric measurements were obtained three times using a digital caliper, with mean values reported. The BR consisted of two distinct heads with separate proximal attachments on the humerus, with the upper head located more proximally than the lower head. Both heads merged into a common tendon at distances of 193.11 mm and 170.69 mm from their respective proximal attachments. The total lengths of the upper and lower heads were 297.70 mm and 276.42 mm, respectively. Each head was independently innervated by branches arising from the radial nerve before its division. This case represents a rare and comprehensively documented example of a twoheaded BR muscle. Awareness of such variations may be clinically relevant, particularly in surgical procedures, imaging interpretation, and neurovascular interventions involving the forearm.