The Extensor Indicis Brevis – A Rare Variation and Its Significance

Abstract

Variations in muscle attachments are valuable in interpreting rare clinical conditions. This case report discusses about the abnormal extensor indicis muscle attachment in left hand of male cadaver and its clinical relevance. The extensor indicis muscle was arising from lunate carpal bone and posterior radiocarpal ligament which further continued as short belly and had its distal attachment on the proximal phalanx of the index finger. This muscular variation has been described in earlier studies with 1.0% incidence. Abnormal origin of extensor indicis may be associated with pain and swelling at the back of the hand. This pain may be confused with other clinical conditions like synovial cyst and ganglion. Knowledge of such rare variations are useful to clinicians, surgeons, occupational and physical therapists for planning better surgical decisions.

Extensor Indicis Brevis Muscle: Report of a Rare Muscular Variant and Classification Proposal

“…The muscle permits independent extension of the index, even in extremes of ulnar or radial wrist deviation (el-Badawi et al, 1995;Komiyama et al, 1999). Though the anomalous variation of extensor indicis tendon is very rare, the anatomical knowledge of such variation is very important while performing tendon graft surgeries in the hand (Arathala et al, 2016). Different anatomical variations of this muscle have been documented in the literature (Georgiev et al); one of the rare variants is the extensor indicis.…”