There are four abdominal muscles. This post covers the transverse abdominis function and its role in helping with back pain. The transverse abdominis, referred to as the corset in pilates, is the deepest of them from the belly button up to the rib cage. Below the rib cage, the transverse switches with the rectus abdominis which moves behind the transverse to attach to the pubic bone.
The transverse abdominis wraps horizontally from the back of the body to the front. There is one transverse muscle on each side joined by a fascial sheet that connects them and allows them to act as one solid muscle.
The transverse abdominis function is to maintain tone of the abdominal organs; when one side works it bends and rotates the body to the side. And whenever we employ deep breathing, for sports or what have you, the transverse abdominis muscle gets involved. Throwing up, coughing, defecating, labor and also forced exhalation— like playing a wind instrument, blowing up balloons or moving heavy objects all bring the transverse abdominis function into play. Pushing out an exhale is an excellent way to feel this muscle at work as the essential transverse abdominis function is to compress the abdomen.
Transverse abdominis function has an interplay with many core components— the spine, and the muscles surrounding the spine, the psoas and the other abdominal muscles as well. Your core is the essential originator of most body movement, as well as being the determinant for the quality of an individual’s posture, aligning the trunk if the muscles all have their proper tone. Because of this building the core is a good way to help with lower back pain.
While this is true, none of the abdominal muscles actually connect to the spine. But the fascia (the connective tissue that wraps the whole body in many different ways) of the transverse abdominis goes all the way around to the outside attachments of the lumbar spine.
The transverse abdominis attaches at the bottom of the rib cage and the top of the iliac crest of the pelvis. The lower part of the muscle runs out of the iliac crest and wraps itself into the inguinal ligament which, among other things, straps down the psoas major.
Decent muscle tone in the transverse abdominis and the internal and external obliques keep the organs in place and supports the lumbar spine helping considerably with back pain relief. Low tone in these muscles allows for the organs to spill out of the abdominal cavity. Too much tone, which is possible but I don’t see it much, can lead to hernia, hemorrhoids, urinary incontinence, and other digestive troubles.