The palmaris profundus is a variant muscle in the forearm which might lead to carpal tunnel syndrome. Due to its variable origins, courses and insertions, it has been classified into subtypes previously, and its often very close relation to the median nerve has been highlighted. Dissection of a male cadaver now uncovered a new reversed variant of this muscle which does not match any of the already described subtypes because of its unique origin from the proximal ulnar shaft and its less pronounced spatial relation to the median nerve. This case shows that there are still unknown variations, which a surgeon may come across during carpal tunnel surgery or any other surgery of the forearm and which may lead to median nerve compression.
