Psoas major muscle

Psoas Major is a long muscle placed on the sides of the lumbar (lower back) region of the vertebral column and brim of the pelvis. Psoas is involved in various activities of daily living like running, dancing, sitting and walking, as it is the primary connector between trunk and lower limbs. It also plays a role in stabilizing the spine and assists in maintaining posture. Psoas major and the iliacus muscle form the iliopsoas, and combined they are seen as the strongest hip flexor muscle.

The upper part of the muscle primarily plays a postural role, whereas the lower part of the muscle has a more dynamic role (movement of the hip).

Functions of the muscle:

• Stabilizes the lumbar spine

• Flexion(bending) of hip

Prolonged sitting and work which requires long sitting periods, tend to put psoas major in shortened and tight positions. Because they are major flexors, weak psoas muscles can cause many of the surrounding muscles to compensate and become overused. That is why a tight or overstretched psoas muscle could cause low back and pelvic pain.

Source: https://www.physio-pedia.com/Psoas_Major

Image: Google images