The transversus
abdominis is the deepest abdominal
muscle. It is the "corset muscle" of the spine and
pelvis (Sacroiliac joint "SIJ"). In the normal situation
it contracts in anticipation of body motion to guard the joints,
ligaments, discs and nerves of the spine and pelvis.
Ultrasound image showing transversus abdominis (centre & left of screen)
The first time a patient suffers from low back pain appears to inhibit the normal activity of this muscle. Once the back pain has resolved this muscle does not automatically switch on again. Other causes of muscle inhibition include: past abdominal surgery, pelvic pain and post pregnancy.
The poor response of the transversus abdominis muscle is thought to expose the spine to further trauma and hence "recurrent back attacks". Each incident becomes a little more severe and consequently further inhibition of the transversus abdominus occurs.
