The muscles that compose the posterior abdominal wall are powerful stabilizers of the lumbar spine and their disfunction is often involved in spine problems (together with anterior muscles). They are:
- Psoas Major: due to the common insertion with the Iliacus, it is often described as Iliopsoas;
- Psoas Minor;
- Quadratus Lumborum: this muscle can be divided into 3 parts from a functional point of view:
- Quadratus lumborum – Iliocostal division;
- Quadratus Lumborum – Iliolumbar division;
- Quadratus Lumborum – Lumbocostal division.