Purvis, Thomas L. The Making of a Myth: Abraham Lincoln's Family Background in the Perspective of Jacksonian Politics.. Journal of the Illinois State Historical Society 75 (Summer 1982): 148-60.
The gluteal group of muscles consists of 3 muscles: Gluteus Maximus, Gluteus Medius and Gluteus Minimus. Gluteus is Greek for rump. Maximus is the largest of the muscles and Minimus the smallest. The role of the Gluteus maximus is different from the medius and minimus muscles because of their attachment points.
the muscle of the buttocks lying between the gluteus maximus and the gluteus minimus, involved in the abduction of the thigh. When it contracts, taking its fixed point at the pelvis, the gluteus medius extends the thigh, which it is also able to abduct.