Supernumerary nipple

A supernumerary nipple is an additional nipple occurring in mammals, including humans. Often mistaken for moles, supernumerary nipples are diagnosed in humans at a rate of approximately 1 in 18 people. The nipples appear along the two vertical 'milk lines', which start in the armpit on each side, run down through the typical nipples and end at the groin. They are classified into eight levels of completeness from a simple patch of hair to a milk-bearing breast in miniature. Polythelia refers to the presence of an additional nipple alone while polymastia denotes the much rarer presence of additional mammary glands. Although usually presenting on the milk line, pseudomamma can appear as far away as the foot. A possible relationship with mitral valve prolapse has been proposed. The Triple Nipple Club is a documentary shown on Channel 4 which explored the biological mystery of the supernumerary nipple. First broadcast on 2 January 2008, it was directed and produced by Dan Louw and commissioned as part of Channel 4's First Cut series. The film focuses on Louw’s attempts to understand why he was born with extra nipples, a condition he shares with the likes of Mark Wahlberg, Lily Allen, and Tilda Swinton, as well as well known TV and film characters such as Scaramanga and Chandler Bing. Fascinated and confused by this seemingly pointless mutation, Louw sets off on a personal journey of discovery to try and unwrap 'the riddle of the triple nipple'. He starts out by consulting the man in the street and even a renowned teratologist, an expert in physical mutations. After testing the notion that extra nipples could be a sign of fertility, he discovers that they are actually an atavism, or evolutionary 'holdover' – a sign of how humans evolved.