<Tr> <Th> MedlinePlus </Th> <Td> 003290 </Td> </Tr> <Tr> <Td_colspan="2"> (edit on Wikidata) </Td> </Tr> <P> In humans, a single transverse palmar crease is a single crease that extends across the palm of the hand, formed by the fusion of the two palmar creases (known in palmistry as the "heart line" and the "head line") and is found in people with Down syndrome . However, it is not an indication that a person with single transverse palmar crease has to have Down syndrome . It is also found in 1.5% of the general population in at least one hand . </P> <P> Because it resembles the usual condition of non-human simians, it is also known as a simian crease or simian line, although these terms have widely fallen out of favor due to their pejorative connotation . </P>

Deep crease in the palm of the hand