rhombus of michaelis rhombus of michaelis the rhombus of michaelis, also known as the michaelis-raute or the quadrilateral of michaelis, is a rhombus-shaped contour (also referred to as kite-shaped or diamond shaped) that is sometimes visible on the lower human back. the rhombus is defined by the following vertices: dimples of venus, the top of the gluteal crease and the lower end of the crease over the spine. the upper half of the rhombus of michaelis is visible just above the bikini bottom. the rhombus of michaelis is named after gustav adolf michaelis, a 19th-century german obstetrician.