Iliolumbar Ligament

Fig. 5. Main function of the iliolumbar ligaments (based on Paul 1989)...

The iliacus muscle originates from the superior two thirds of the concavity of the iliac fossa, from the inner lip of the iliac crest, from the ventral sacroiliac and iliolumbar ligaments, and from the upper, lateral surface of the sacrum. In front, it reaches as far as the anterosuperior and anteroinferior iliac spines, and receives some fibers from the upper part of the capsule of the hip joint. It inserts into the lateral side of the tendon of the psoas major, which inserts into the lesser trochanter of the femur. 

From the posterior two inches of the iliac crest and the iliolumbar ligament. 

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