Abdominal Muscles and Back Pain

Abdominal trigger points can refer to the low back

Many people are aware that the abdominal muscles have something to do with back pain and this awareness is centered around 'core' support and the role of these abdominal muscles in back support. While this is certainly the case, my patients are less aware that the abdominal muscles can be directly tied to the back pain they experience. The rectus abdominis specifically can harbor trigger points, or sensitive contractile knots, that can cause pain not necessarily in the abdomen, but can instead refer pain to the back.

Regardless if you have a developed rectus abdominis or not, this is the muscle that people refer to when the discuss a 'six pack' ab. Technically, there are four grouping of muscles on either side, and each of these compartment are bordered by a tendinous intersection. The upper compartment is lies over the lower ribcage and this compartment is less visible when people do have 'six pack abs', so you are really seeing the lower three compartments on either side.

The rectus abdominis attaches from the pubic bone to the lower ribcage and sternum. The muscle is involved with flexion of the trunk, forced exhale and compression of the abdominal organs.

While it is actively involved in forced expiration or exhale, when the muscle becomes rigid and restricted, it can reduce the ability to take a good, deep inhale and this is most frequently the case when this muscle becomes a component of low back pain.

There is a characteristic referral pattern when this muscle is contributing to back pain which can be seen on the image to the right. The low back portion of the refer specifically usually is associated with trigger points in the umbilical region, in my opinion, and they can frequently even occur in the tendinous intersection in this region. This image to the right shows and X at the pubic bone attachment which can also occur, but I still find this occurs more frequently at the umbilical region. The mid back pain referral is more often at the region just below the lower ribcage and close to the xiphoid process which is the lowest part of the sternum or breastbone.

Many people with low back pain will look at the referral that travels across the low back/upper pelvic region and say, 'That describes my back pain!" It could be the case, then that the rectus abdominis is a contributor. It is the case, thought, that there are other frequently causes of this horizontal distribution of low back pain. Specifically, the joints of the lower spine, referred to as facet joints, can become irritated and cause a similar pain distribution. Below is and image that illustrates this referral pattern and you can see that there is some overlap.

It can be a combination of causes, all contributing to the pain that brings people in to see me. Palpation can be used to see if this muscle is referring pain, but there are also other clues. Urinary problems, digestive disturbances, and dysmenorrhea (painful periods) can all be associated with trigger points in the rectus abdominis. Clinically, it is worth investigating if this important muscle is contributing to the back pain and other problems, and then adding protocols to treat it into the mix. Acupuncture, dry needling, manual therapy and specific corrective exercises are all helpful and tools I use for this trigger points in this muscle and for back pain in general.

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Iliac Crest Syndrome

Iliac Crest Syndrome - A Common Cause of Low Back Pain

Fig. 1: Pain site at the posterior iliac crest region

Pain experienced at the iliac crest is a frequent low back condition affecting patients seeking help from Sports Medicine Acupuncturists®. The iliac crest is the top (or ‘crest’) of the ilium, which is the most superior or upper portion of the pelvic structure. If you were to place your hands on your hips, they would be resting on the iliac crest. Pain at the iliac crest, referred to as ‘iliac crest syndrome,’ is experienced at the posterior (back) portion of the iliac crest and can be persistent (Fig. 1).

Fig. 2: Palpation of yaoyan at 
the superficial and deep vectors

This pain is at an acupuncture point called yaoyan which is a commonly used 'extra point'. Extra points are points which are not on main acupuncture channels, but have been found to be clinically important nonetheless. This particular extra point is found at the attachment site of two important back muscles. Depending on the depth, these muscles are either the iliocostalis lumborum or the quadratus lumborum (Fig. 2).

The iliocostalis lumborum is the more superficial of the two of these muscles. It is one of three muscles which are part of a group called the erector spinae (Fig 3 left image). This is the group of muscles that span the back from the hip through the neck and run parallel to the spine. The iliocostalis lumborum is the ‘lumbar’ or low back portion of this group; it runs from the top of the iliac crest (the ‘ilio’ part of the name) to the ribs (the ‘costo’ part of the name). This muscle then continues upward (but it is then called the iliocostalis thoracic and iliocostalis cervicis) and is the most lateral of the three muscles of the erector spinae. The iliocostalis functions with the other muscles of this group to perform extension of the torso, which is the motion involved in bending backward. However, since this muscle is a bit more lateral than the others in the group, it is also involved in side bending motion. In this case, only one side is primarily involved–the right muscle in right side bending and the left in left side bending.

The quadratus lumborum is a deeper muscle underneath the iliocostalis (Fig. 3 right image). It runs from the iliac crest and has attachments on the lumbar (low back) vertebrae, and ends at the 12^th (lowest) rib in the back. This muscle laterally flexes the trunk. It does this by shortening the space between the top of the hip and the 12^th rib. This would either pull the rib towards the hip (sidebending on that side) or pull the hip towards the rib (elevating or hiking the hip up on that side).

Both of these muscles have attachments on the iliac crest and both can become pain-producing sites. In both cases, these muscles would be in a shortened position when the hip is hiked on the side of pain. This is frequently what is seen with iliac crest pain.

Fig. 3: Image on the left shows the iliocostalis which is the lateral muscles of the erector spinae group. The image on the right has this group removed to highlight the deeper quadratus lumborum muscle. Both are common sites of pain at the iliac crest. Both images are from Netter's Atlas of Human Anatomy.

When the hip is elevated on one side, as is often the case with iliac crest syndrome, it is not simply the muscles discussed which are involved. Other muscles whose job it is to stabilize the hip and prevent it from elevating are also part of the overall picture. The gluteus medius and minimus are the primary muscles which do this, and these muscles have a propensity to become inhibited and fail in their stabilization roll.

When treating iliac crest syndrome, it is important to address all of the muscles involved in the imbalance. This includes both the shortened and overactive muscles such as the iliocostalis and quadratus lumborum, along with the inhibited and overlengthened muscles such as the gluteals. Acupuncture and manual therapy are powerful treatment options to correct these imbalances, and corrective exercises performed by the patient can solidify treatment at continue to return function.

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