Psoas major muscle

• Side surfaces of thoracic vertebra 12
• Lumbar vertebrae 1-4 and intervening intervertebral discs deeper portion: ribs extensions lumbar vertebrae 1-5

• Diffraction (flexion )
• Eversion ( external rotation )

Spine:

• Diffraction (inclination )
• Lateral bending ( lateral flexion )

Segment = L1 -L4

The psoas major ( Latin for " large lumbar muscle ") is a skeletal muscle of the lower extremity, specifically the anterior ( ventral ) layer of the posterior ( dorsal) hip muscles. He is functionally grouped with the iliac muscle (musculus iliacus ) for lumbar -iliac muscle ( Musculus iliopsoas ).

On the large lumbar muscle a small lumbar muscle ( psoas minor) may be in less than half of all people yet; this muscle is not trained in all mammals.

Course

The superficial portion of the large lumbar muscle originates from the lateral surfaces of the twelfth thoracic vertebra, the first four lumbar vertebrae and the corresponding intervertebral discs ( intervertebral disks ).

The deep portion originates ( costal processus ) of the ribs extensions of the first to fifth lumbar vertebral body.

Both parts combine with the iliac muscle and get enveloped in their muscle binding ( fascia ) ( iliac fascia ) as lumbar -iliac muscle by muscle Gate ( muscular lacuna ) to the small trochanter ( lesser trochanter ) of the femur, to which he attaches.

Function

In the hip joint the muscle causes flexion (flexion ), he is the most powerful hip flexors of man. He is also responsible in the hip joint for the eversion ( external rotation ). Furthermore, it results in one-sided tension side bending ( lateral flexion ) and with bilateral tension diffraction (inclination ) in the spine.

Psoas sign

The right great lumbar muscle also provides an indication of an inflammation ( appendicitis) of the appendix ( vermiform appendix ). In strong contraction ( contraction) of the muscle, eg during flexion of the right thigh, it comes through the induced pressure on the appendix to pain in the right lower abdomen.