The extensor digitorum brevis manus is one of the rare anatomic variations which occur on the dorsum of the hand. Only some 295 articles were found worldwide in an extensive bibliographic review carried out in 2003. This muscle was dissected bilaterally on a male corpse at the Human Anatomy Laboratory of the Morphophysiological Department of the “Faculty of Medical Sciences of Minas Gerais”. It is an elongated, small muscle, originating at the carpal bones and at the extensor retinaculum and inserting into one of the tendons of the finger’s extensor muscle. Even though it does not present an essential function in the movement of the fingers nor the hand, it can lead to pain when hypertrophied, creating the need for clinical or even surgical treatment.