A canal through the medial epicondyle at the distal end of the vertebrate humerus, usually traversed by the median nerve and brachial artery.
Comment:
[taxon-note] "It is often present in primitive placentals, such as the enigmatic Madagascan Plesiorycteropus. In most Neotominae and all Tylomyinae among cricetid rodents, it is located above the medial epicondyle of the humerus, but it is absent in all Sigmodontinae and Arvicolinae and this trait has been suggested as a synapomorphy for the former subfamily.[WP]"; [taxon-note] "Primitive amniote feature found in primitive reptil-like amphibians (Romeer) [http://www.jstor.org/discover/10.2307/2422468]"