Psoas+major

toc =Description= Psoas major has a long fusiform shape. It is located on the lateral part of the lumbar region of the vertebral column and at the border of the lesser pelvis; in short it is located in the posterior abdominal wall. The psoas major is divided into a superficial and a deep part. The deep part arises from the transverse processes of the lumbar vertebrae 1-5. The superficial part originates from the lateral surfaces of the vertebrae T12 to L5, and from proximal invertebral discs. This muscle runs downwards and laterally to the anterior side of the pelvis and it inserts on the lesser trochanter of the femur.The psoas major is supplied by the lumbar arteries 1-4. The innervation is through lumbar plexus, the anterior rami of L1 to L3 and the spine nerves. Psoas major muscles actions are flexion and external rotation of the hip joint. On the lumbar spine, unilateral contraction assists in the side flexion of the trunk, while bilateral contraction elevates the trunk from its supine position. It forms part of a group of muscles called the hip flexors, whose action is primarily to lift the upper leg towards the body when the body is fixed or to pull the body towards the leg when the leg is fixed. Daily activities that we use the muscle for is to kick, swim, sit and when doing sit-ups. = = =Interactions and relations to other Muscles = The psoas major muscle, together with the iliacus muscle form a muscle called the iliopsoas. This muscle pair is found on the edges of the thigh and also mainly on the abdominal cavity. The psoas major and the iliacus muscle have a common insertion, they insert in the lesser trochanter of the femur. The iliacus and the psoas major perform hip flexion, and lateral rotation of the hip. Psoas major muscle also has similar muscle action with hip lateral rotators, namely: piriformis, obturator internus, gemellus superior and gemellus inferior. The antagonists of the psoas major muscle are the gluteus maximus, semitendinosus, semimembranous, biceps femoris (longhead) and the posterior fibres of the adductor magnus. The iliacus and the psoas major are synergists of each other. The gracilis, sartorius, and rectus femoris, which are muscles in the anterior compartment of the thigh, also flex the hip as the psoas major, though they are not the main hip flexors. In addition to that, the sartorious muscle also laterally rotates the hip.
 * Author: Oritonda Rejoice Makahane**

=Relevance to Physiotherapy = This muscle is relevant to physiotherapy because in exercises of the lower limb the psoas major is involved. As a Physiotherapist one needs to know the muscles that are working during hip flexion and lateral rotation. The physiotherapist will be able to decide which muscle is damaged by considering the muscle location and the muscle action, in this way suitable muscle strengthening exercises will be prescribed to the patient. The psoas major is also relevant to physiotherapy as this muscle functioning can be tested by performing passive and active movements such as hip flexion and lateral rotation; failure, pain or weakness in performing the movements may indicate an injury in the muscle and a more better and clearer diagnose will be made. Some techniques such as massage can help relieve lower back pain and lateral abdominal pain caused by the psoas major. If a physiotherapist knows where the psoas major is; he/she can be able to locate the muscle's trigger points and compress and massage them in order to stop the pains. In order to free tight psoas major muscle, the physiotherapist should be able to know the psoas major muscle and perform some stretch exercises directly on the muscle in order to free it. This muscle is also relevant to physiotherapy because it is involved in the treatment of the iliopsoas syndrome, which is the dysfuntion in the lower back. This muscle is also relevant when treating sports injury.

=Links to online interactive material = []

media type="youtube" key="ljuYus2kgrA" height="315" width="560" media type="youtube" key="TuGpwS8dBJU" height="315" width="560" =References= Introducing: The psoas muscle. Marguerite ogle March 11 2011 The principle artery of the psoas muscle. pillet et al;.( 1989) []