Variation and clinical significance of extensor pollicis brevis: A study in south Indian cadavers

Background: de Quervain's disease is a condition in which there is pain in the radial styloid process caused by stenosing tenosynovitis of the abductor pollicis longus (APL) or/and extensor pollicis brevis (EPB) tendons in the first extensor compartment of the wrist. In this study we studied variations in the tendons of the EPB in the first extensor compartment and its site of insertion. Methods: One hundred fifty six upper limbs from adult cadavers of south Indian origin were dissected to observe the number of EPB tendons and the presence of an osseo-fibrous septum in the first extensor compartment of the wrist. Results: The EPB had a single tendon in 133 limbs, double tendons in 17 limbs and triple tendons in only 6 limbs. The EPB was present in all of the upper limbs in our study. In 34.6% of cases, the tendons of the EPB were separated from the tendons of APL by an osseo-fibrous septum in the first extensor compartment. Conclusion: Variation in the number of EPB tendons and site of insertion should be taken into consideration by clinicians and surgeons when performing surgical decompression of the first extensor compartment of the wrist in de Quervain's syndrome. Surgical failure may occur due to overlooking variations in EPB tendons or septation of the first extensor compartment.