Variation in the Forearm Extensor Muscle: case report

The Extensor Carpi Radialis Longus (ECRL) and the Extensor Carpi Radialis Brevis (ECRB) are muscles of the posterior forearm compartment. variations in this area of the forearm are common and are usually diagnosed during surgery. Sometimes these variations are symptomatic and can be helpful in clinical procedures such as surgery. Diagnosis and identification of abnormalities can be used in academic studies to evaluate limb function. Reporting such variations is important in clinical practice and will help treat limb dysfunction. In this report, we report two cases of ECRL and ECRB muscle tendon variations in the upper third of the forearm.

During routine dissection of the body of a 70-year-old man fixed in 10% formalin in the Department of Biology and Anatomy, Shahid Beheshti University of Medical Sciences, Tehran, two cases of ECRL and ECRB muscle tendon variations were observed in the upper third of the left forearm. The fascia of the ECRL and ECRB muscles were separated, and following the ECRL muscle from the external epicondyle of the humerus to the outer third of the forearm, we observed that the tendon of this muscle was divided into two branches. We also observed that the ECRB muscle tendon split into two branches slightly below its origin. The branch had moved obliquely toward the lower end of the radius. at the lower end of the forearm, this tendon was connected to the ECRL muscle tendon by passing over the sub-branch of the ECRL muscle tendon and the depth of the retinaculum extensor. The submandibular tendon was attached to the base of the second Metacarpal bone along with the ECRL muscle tendon. The main branch of this muscle also had its main path to the lower end of the forearm. The lower end of the forearm was connected to the dorsal base of the second and third metacarpals by passing under the retinaculum extensor.

Knowing these variations can help radiologists and surgeons in diagnosis and treatment.