Psoas muscle


The psoas muscle is a hip muscle and consists of the psoas major muscle and the psoas minor muscle in half of people. Since the psoas major muscle attaches itself to the iliacus muscle in its course, it is also often called iliopsoas muscle.

The psoas major muscle is one of the large muscles of the lower extremity and belongs to the anterior group of the posterior hip muscles.


The approach the psoas major muscle is in two parts divided.

  1. Once it springs from the Side face of twelfth thoracic vertebra, the first four lumbar vertebrae and the Band washers.
  2. The second part arises from the Transverse processes the Lumbar vertebrae one to five. The psoas major muscle then unites with the iliacus muscle and runs through the iliopsoas muscle Lacuna musculorum (a muscle gate) to the Thighbones and then attaches to the lesser trochanter, which is a small process on the Thighbones represents.


In the hip joint, the muscle has the following tasks:

  • he bends ( Flexion)

  • he turns the leg to Outside (External rotation)

  • Side tilt with unilateral tension (Lateral flexion)

Sensitive supply of the psoas major muscle

The Psoas major muscle is from Femoral nerve innervated. Also still pull direct branches from the Lumbar plexus (L 1-4) into the muscle and partially innervate it as well.

Psoas sign

The Psoas sign is a sign of a appendicitis. There bends one a leg in the hip, it comes about with this movement Pain is the psoas sign positive.

Psoas minor muscle

The Psoas minor muscle is like the name suggests small psoas muscle. He is Not with every person pronounced and has hardly any function.

He rises from the twelfth thoracic vertebra and from the first lumbar vertebra.

The M. Psoas Minor consists of one long tendonthat are in the Iliopsoas muscle irradiates. Like the psoas major muscle, it attaches to the minor trochanter Thighbone at.

The muscle is innervated by the Lumbar nerves 1-3.

Figure psoas muscle

Figure psoas muscle

Psoas muscle

  1. Lumbar muscle -
    Psoas major muscle
  2. Lumbar muscle -
    Psoas minor muscle
  3. Twelfth thoracic vertebra -
    Vertebra thoracica XII
  4. Iliac crest -
    Iliac crest
  5. Lumbar and sacrum kink -
  6. Great Rolling Hill -
    Greater trochanter
  7. Small rolling hill -
    Lesser trochanter
  8. Pubic bone - Pubis
  9. Iliac scoop -
    Ala ossis ilii
  10. Thigh shaft -
    Corpus femoris
  11. Fifth lumbar vertebra -
    Vertebra lumbalis V
  12. First lumbar vertebra -
    Vertebra lumbalis I

You can find an overview of all Dr-Gumpert images at: medical illustrations

Pain in the psoas muscle

The psoas muscle and the iliacus muscle form a functional unit, the M. iliopsoas. The function of the M. iliopsoas is to bend the hip, whereby the M. psoas is also responsible for the movement of the lumbar spine.

Read more about the topic here Iliopsoas

If the muscle is stressed too much, it or its tendon can become inflamed or tension can arise. If the muscle is not used enough, it can lead to muscle shortening. Pain often occurs in the lumbar area and is usually clearly defined around the spine, but can also radiate into the thigh. It is especially with M. psoas that the pain increases when standing or standing up. If an upright gait is no longer possible, this indicates tension or shortening of the muscle. Shortening often occurs during seated activities (truck driver, computer and general desk work) because the muscle is constantly contracted in this position. If the muscle is stretched too quickly, incorrectly or too much, it can lead to muscle tension. Painkillers or heat patches can be used for a short time, but if the pain is permanent or has persisted for several weeks, a doctor should be visited. Physiotherapy can lead to relief and exercise or back training can be very helpful in avoiding incorrect movements in the long term and preventing the associated pain. Pain in the psoas muscle should not be confused with the "psoas sign" that occurs in the context of appendicitis.