A Rare Extra Head on the Arm Muscle

Original Title

Four-Headed Biceps Brachii Muscle, with a Rare Pectoralis Major Supernumerary Head: A Cadaveric Case Report

Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms

Summary

Doctors found a rare extra part of a muscle in someone's arm that most people don’t have. It was found while studying a body after death.

Sign up to see full results

Get access to research results, context, and detailed analysis.

Surprising Findings

A single person had a four-headed biceps muscle with a rare pectoral head attachment — a combination never before detailed in medical literature.

While accessory heads of the biceps are occasionally reported, the co-occurrence of both an accessory humeral head and a supernumerary pectoral head in a unilateral configuration is extremely rare and had not been formally documented until now.

Practical Takeaways

Medical professionals should consider anatomical variation as a possible cause when patients present with unexplained upper limb pain or nerve symptoms.

low confidence

Unlock Full Study Analysis

Sign up free to access quality scores, evidence strength analysis, and detailed methodology breakdowns.