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.