Anomalous extensor hand muscle: “extensor digitorum brevis manus”

Abstract

In the dorsal region of the wrist and hand, various accessory and supernumerary muscles are described; they can act as simulators and produce clinical entities (ganglion, synovial cysts, etc.). The clinical diagnosis is increasingly accessible; ultrasound and magnetic resonance have allowed to evaluate their nature and extent. The presence of this muscle usually goes unnoticed without symptoms, but it can cause swelling and pain in the carp; it is accentuated with activities, especially those requiring the forced extension of the wrist and fingers. It can manifest bilaterally in one third of patients and the incidence did not differ between males and females. When symptoms are severe, surgical treatment is indicated with the complete resection of the muscle or the division of the extensor retinaculum; both techniques achieve good results; in some cases, it has been used as a flap to reconstruct tendon injuries at other levels. The frequency of this muscle is very low; our literature review will help to consider this condition among the various differential diagnoses in the region of the wrist and hand.