The origin of the muscle originates on the inner surface of the ilium and the lower borders of the transverse processes (l1-l5), sides of the bodies of the last thoracic vertebra (t12), lumbar vertebrae (l1-l5), intervertebral fibrocartilages, and base of the sacrum.
insertion: lesser trochanter of the femur and shaft just below posts minor; pectineal line (of pubis) and iliopectineal eminence
a) flexion of the hip
b) anterior pelvic rotation
c) flexion of lumbar spine (sagittal)
d) external rotation of hip
e) transverse pelvic rotation contra laterally when ipsilateral femur is stabilized (transverse)