Extensor digitorum muscle in cadavers: a case report

Abstract

Humans have many characteristics that separate them from other mammals, but one of the most noticeable and important ones is being capable to execute fine motor skills with their hands. It’s essential to understand the muscles that are present in the hands to perform surgeries with much care, since humans rely on their hands to fulfill basic needs, such as eating and personal care. The extensor digitorum muscle has 4 tendons that extend to the medial four digits of the hand. The anatomic variation studied in this case report is in the middle finger, which doesn't usually have an extensor digitorum muscle (EDM), but does on this occasion. A 40-year-old male cadaver was dissected, in which the skin was partially removed with care, followed by the subcutaneous tissue and then the fascia of the forearm. The cadaver was fixed with 10% formaldehyde, conserved in a storage tank for a year, and only dissected after this period. The belly of the EDM in the middle finger was found in the posterior region of the forearm. showing a volume similar to that of the extensor digitorum of the index finger and the extensor digitorum of the thumb. It exhibited two tendons, one being thin and the other thick. This belly was found in the posterior region of the left forearm, originating from the medial side of the distal third of the ulna and inserting itself onto the base of the proximal phalanx of the middle finger. It’s important to note that the right middle finger did not show this anatomic variation.