Incidence of gluteus quartus in human cadavers

Human gluteal musculature is described as three distinct muscles: gluteus maximus, gluteus medius and gluteus minimus. There also exists a lesser‐known fourth muscle, gluteus quartus (also referred to as gluteus scansorius.) First mentions of gluteus quartus appear in scientific literature from the early 1800's, with descriptions of chimpanzee anatomy. In an 1885 paper it was proposed the human iliofemoral band is a degenerated remnant of the gluteus quartus, later refuted by a paper published in 1900. Mention of an accessory muscle anterior to gluteus medius has variably appeared in older French and German anatomy texts. A single specimen cadaveric study in 1954 gave the first detailed description of gluteus quartus in humans. A recent study of gluteus medius and gluteus minimus found gluteus quartus in 2 of 16 specimens. The purpose of our study was to determine the prevalence of gluteus quartus in both the male and female population. Careful dissections were carried out on 45 embalmed cadaveric hips (29F, 16M). Gluteus quartus was present either as small fibers or a distinct muscular bundle. The Gluteus quartus was observed as fibers in 44% of males and 41% of females, gluteus quartus was observed as a bundle in 50% of males and 31% of females. There was an overall incidence of 80%, suggesting that gluteus quartus is more prevalent in humans than previously thought.