Abstract
During routine dissection for the undergraduate medical students, we encountered an unusual, additional muscle in the anterior compartment of the forearm. This muscle took origin from the anterior surface of the radius in common with the flexor digitorum superficialis muscle. It had a tendon of origin and a tendon of insertion. Its fleshy radial belly and the tendon of insertion, crossed superficial to the median nerve. The muscle was inserted partly to the flexor retinaculum and partly to the undersurface of palmar aponeurosis. The observations made by us in the present case will supplement our knowledge of variations of the muscles in this region which could be useful for hand surgeons as it could possibly compress the median nerve because of its close relationship to it.
Highlights
Variations in muscles of the extensor compartment of the forearm are quite common
The superficial muscles are pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis (FDS) and flexor carpi ulnaris and they take a common origin from the medial epicondyle of the humerus
In a South Indian cadaver aged approximately 60 years, during routine dissection for undergraduate medical students, we found an abnormal muscle in the anterior compartment of the left forearm
Summary
Variations in muscles of the extensor compartment of the forearm are quite common. in the flexor compartment not many variations are noted and occurrence of an additional muscle is very uncommon. The superficial muscles are pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis (FDS) and flexor carpi ulnaris and they take a common origin from the medial epicondyle of the humerus. The picture shows the exposed anterior compartment of the forearm and proximal part of the palm to show the additional muscle belly (AMB) with two tendons, a tendon of origin (TO) and a tendon of insertion (TI). The fleshy part of the muscle and the long tendon of insertion crossed superficial to the median nerve from lateral to the medial side (Figure 1 and Figure 2). TfbtFoehirgletlyuhaperr(iAemcptMa2ualrmBne)dasarphnaodlpmwoitsansretthureernogdeisoxisnpoatonsofedisdnfhlsaeoenxwrtoteirtorhinroeer(taTicdnIoda) mcigtueipoltantmriantlmgmaeutntstacctlheed The picture shows the exposed anterior compartment the forearm and palmar region to show the additional muscle belly (AMB) and its tendon of insertion (TI) getting attached to the palmar aponeurosis and flexor retinaculam. FDS- flexor digitorum superficialis; FCR- flexor carpi radialis, MN- median nerve, RA- radial artery; SPA- superficial palmar arch
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
