Anteriorly, the psoas major (and occasionally psoas minor) originates along the spine between the rib cage and pelvis.

http://en.wikipedia.org/wiki/Pelvis

Anteriorly, the psoas major(and occasionally psoas minor) originates along the spine between the rib cage and pelvis. Theiliacus originates on the iliac fossa to join psoas at the iliopubic eminence to form the iliopsoaswhich is inserted into the lesser trochanter. The iliopsoas is the most powerful hip flexor.