a long, flat, narrow muscle extending obliquely from the front of the hip to the inner side of the tibia, assisting in bending the hip or knee joint and in rotating the thigh outward: the longest muscle in humans.
anatomy a long ribbon-shaped muscle that aids in flexing the knee
[C18: New Latin, from sartorius musculus, literally: tailor's muscle, because it is used when one sits in the cross-legged position in which tailors traditionally sat while sewing]