Low back pain is one of the most common complaints for musckuloskeletal problems and can be addressed through maintaining/developing core strength and coordination. The core can be defined as the musclo-skeletal system that starts from just below the chest and continues all the way down to the knees. All of these muscle groups contribute to the stability of the core and its ability to create pain free movement.
ANATOMY and FUNCTION:
Bones of the lower back include the lumbar spine (5 lumbar vertebrae), the sacrum, and coccyx. The lumbar vertebrae provide protection to the spine, while serving as attachment sites for muscles to produce movement in various planes of the body. Nerve roots that innervate the muscles of the body exit the lumbar spine through the intervertebral foramen. (1) In between each lumbar vertebrae is an intervertebral disc that acts to cushion the forces transmitted through the body. The lumbar vertebrae can be compared to a jelly donut, with the outside made of a tough tissue called the annulus fibrosus. Inside lies the nucleus propulsis which is comprised of 60-70% water, with similar consistency to the jelly in a donut. This composition allows for some deformity while still being strong enough to cushion forces between the vertebrae.
Figure 1
Unfortunately, the water content of these discs decrease over time and by the age of 60 the discs reach a maximum state of dehydration. This decreases the size of the disc, which subsequently decreases the space provided by the intervertebral foramen to allow the nerve roots to exit. (1) This degenerative process can predispose an individual to certain radicular pathologies. Time and repeated stress on the disc can also weaken the annulus fibrosis and cause the nucleus propulsis to bulge out (Bulging Disc). Further damage to the nucleus propulsis can cause the nucleus propulsis to herniate Figure 2 through the annulus fibrosis and place pressure on the nerve (Herniated Disc). (1) Pressure on the nerve produces radicular symptoms and can be described as one or a combination of the following: pain down the leg, numbness, tingling, or muscular weakness in the hip, leg or foot. If you are experiencing any of these symptoms medical attention should be sought.
A common way that muscular skeletal pain is produced is Figure 3 through muscle strains to the lower back. A muscle strain can be described as when a muscle has been stretch or torn by a strong sudden movement. (2) When the back is placed in awkward positions muscles can become overloaded with tension, thereby creating trauma to the muscle fiber. The muscle strain can take place in either the muscle, musculo-tendon junction, or the tendon.
Another common source of lower back pain produced through uncoordinated movements are muscle spasms. Here the muscle is overstretched and in attempt to protect itself muscle guarding occurs (process of muscle trying to protect itself by reflexively contracting) which creates a “cramp” or spasm.
Ligament sprain are less commonly seen as the product of low back pain but must be appropriately assessed if suspected. The lumbar vertebrae are connected to each other and pelvic bones by various ligaments. Ligaments are tough connective tissue that attaches bone to bone. When the lumbar spine is placed is a disadvantaged position, under heavy loads, muscles fail in their support and the spine stability is then dependent on ligaments. If the force is great enough small micro tears develop in the ligament and a sprain is the result.
Injuries to the bones are usually caused by repetitive stress and maladaptive movements at the lower back. The movements tend to be seen in sports that require a lot of lumbar extension, such as volleyball and gymnastics. The forward slippage of one vertebrae on another places stress on the pars interarticularis. Spondylolysis is the resultant defect in the bone when to much repetitive stress has resulted. If left untreated this defect can progress to spondylolithesis which is an actual separation of the pars interarticularis into two pieces. Spondylolithesis is most commonly seen in adolescents and women. Gymnasts are four times more likely to develop this condition. Symptoms usually include pain in the lumbar spine that may radiate into the buttocks and Figure 4: Spondylolithesis upper portion at the back of the outer thigh. (1)
Appropriate recognition and treatment of low back pain is essential to long-term success. Early and effective treatment can lessen the impact of low back pain and can allow for long-term pain free activity. Addressing both postural and functional aspects of low back pain are essential tools for injury prevention.