Multiple variations of the extensor tendons of the forearm

Anatomic variations of the extensor tendons of the forearm are frequent and its knowledge is important to assess the diseased and traumatized hand. During routine cadaveric dissection in the Department of Anatomy, Kasturba Medical College, Mangalore, India, we came across unusual variations in the left upper limb of a 51-years-old male cadaver. The variants are, the complete absence of the extensor pollicis brevis (EPB), the abductor pollicis longus (APL) having six slips of insertion with additional muscle slip from the brachioradialis (BR). The extensor digitorum communis (EDC) had five tendon slips, the extra tendon splits close to the metacarpo-phalangeal (MP) joint and contribute to the tendons of the ring and little fingers. The number of accessory tendons of APL has functional significance in the development of de Quervain's stenosing tendovaginitis. The present case is unique in the sense that, all the three variations are present in the ipsilateral upper limb. The occurrence of these anomalies and its clinical and embryological significance are discussed.