Iliopsoas

Iliopsoas (hip flexor)
Anterior hip muscles. The iliopsoas is not labeled but can be seen as the psoas major and the iliacus join inferiorly.
Details
Origin	Iliac fossa and lumbar spine
Insertion	Lesser trochanter of femur
Artery	Medial femoral circumflex artery and iliolumbar artery
Nerve	Branches from L1 to L3
Actions	Flexion of hip
Antagonist	Gluteus maximus and the posterior compartment of thigh
Identifiers
Latin	Musculus iliopsoas
Dorlands /Elsevier	m_22/12549330
TA	A04.7.02.002
FMA	64918
Anatomical terms of muscle []

The iliopsoas (ilio-so-as) is the combination of the psoas major and the iliacus at their inferior ends. These muscles are distinct in the abdomen, but usually indistinguishable in the thigh. As such, they are usually given the common name iliopsoas and are referred to as the "dorsal hip muscles". or "inner hip muscles". The psoas minor does contribute to the iliopsoas muscle.

The psoas major originates along the lateral surfaces of the vertebral bodies of T12 and L1-L3 and their associated intervertebral discs. The iliacus originates in the iliac fossa of the pelvis.

The psoas major unites with the iliacus at the level of the inguinal ligament and crosses the hip joint to insert on the lesser trochanter of the femur. The iliopsoas is involved in flexion and lateral rotation (supination) of the thigh. If the limb is fixed they involve in flexion of the trunk.

It is a composite muscle. The psoas major is innervated by direct branches of the anterior rami off the lumbar plexus at the levels of L1-L3, while the iliacus is innervated by the femoral nerve (which is composed of nerves from the anterior rami of L2-L4).

The iliopsoas is the strongest of the hip flexors (others are rectus femoris, sartorius, and tensor fasciae latae). The iliopsoas is important for standing, walking, and running. The iliacus and psoas major perform different actions when postural changes occur.