Psoas major muscle
| Psoas major muscle |
|---|
|
| anterior hip muscles |
| origin |
superficial part:
|
| approach |
| as lumbar iliac muscle ( Musculus iliopsoas ) on the lesser trochanter of the thighbone ( femur ) |
| function |
Hip joint :
Spine :
|
| Innervation |
|
Lumbar plexus and femoral nerve
Segment = L1-L4 |
The psoas major muscle ( lat. For "large lumbar muscle") is a skeletal muscle of the lower extremity , more precisely the front ( ventral ) layer of the rear ( dorsal ) hip muscles. It is functionally combined with the iliac muscle ( musculus iliacus ) to form the lumbar iliac muscle ( musculus iliopsoas ).
Less than half of all people may have a small lumbar muscle ( Musculus psoas minor ) on top of the large lumbar muscle (inconstant muscle); this muscle is not developed in all mammals .
course
The superficial part of the large lumbar muscle arises on the side surfaces of the twelfth thoracic vertebrae , the first four lumbar vertebrae and the corresponding intervertebral discs ( Disci intervertebrales ).
The low proportion rises to the rib projections ( costal processes of the first to fifth lumbar vertebral body).
Both parts unite with the iliac muscle and, enveloped by their muscle ligament ( fascia ) ( fascia iliaca ) as a lumbar iliac muscle, pass through the muscular portal ( lacuna musculorum ) to the small rolling hillock ( trochanter lesser ) of the thigh bone , where it attaches.
function
In the hip joint , the muscle causes flexion ; it is the strongest human hip flexor. He is also responsible for the outward rotation ( external rotation ) in the hip joint . In addition, it causes side bending ( lateral flexion ) with one-sided tension and flexion ( inclination ) in the spine when tensioned on both sides .
Psoas sign
The right large lumbar muscle also provides an indication of an existing inflammation ( appendicitis ) of the appendix ( appendix vermiformis ). With strong contraction ( contraction ) of the muscle, e.g. B. when bending the right thigh, the pressure on the appendix causes pain in the right lower abdomen.
See also
literature
- Walther Graumann, Dieter Sasse: Compact textbook anatomy . Volume 2, Schattauer Verlag 2004, ISBN 3-7945-2062-9 , p. 130.
- Franz-Viktor Salomon: muscle tissue. In: Anatomy for veterinary medicine. 2nd ext. Edition. Enke, Stuttgart 2008, ISBN 978-3-8304-1075-1 , pp. 147-234.