Ligaments And Muscles - The Anatomy Of Your Back: Back Pain

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Ligaments and muscles

Your spinal ligaments and muscles attach to the spinous and transverse processes. The ligaments connect the vertebrae to one another, making the spine a flexible column. The muscles enable your trunk to move, bend, twist, and stretch. More important, they limit and control back motions and support the spine — a bit like guy wires that support a tall television relay tower. They can be divided into three general groups (see Figure 3A).

Figure 3: Back muscles and nerves A. Three groups of muscles — the erector spinae, abdominal muscles, and iliopsoas muscles — support your spine and control back movements. The abdominal muscles also form your abdominal cavity, and the iliopsoas muscles allow you to flex your hips and help balance your trunk when you're standing. B. Your spinal cord runs from your brain down through your spinal canal and ends in the lumbar area. Nerve roots exit through the two narrow channels, one on each side, between adjacent vertebrae. In the lumbar spine, the remaining, lowermost nerve roots form a bundle of strands that resemble a horse's tail — in Latin, the cauda equina.

The flat abdominal muscles in front are attached to the pelvis below and the ribs above. These muscles form the cavity that contains your stomach and other abdominal organs; they also support your lumbar spine in front.

The two iliopsoas muscles, one on each side of your lumbar vertebrae, are attached to the bodies of the vertebrae and to the inside of your pelvis. They pass downward in front of your hip joints and attach to the thighbones. These muscles not only support your spine but also flex your hips and help balance your trunk on your lower limbs when you stand.

The erector spinae (Latin for "upholder of the spine") — located to the left and right of your spine in the rear — are the large muscle masses visible in the lower part of your back. They are composed of many muscle groups attached to the bony processes on the vertebrae, as well as to the pelvis below and the rib cage and thoracic and cervical spines above. They are the major supports of your spine during lifting. If you have acute back pain, these are the muscles that may go into spasm.

Last updated:	January 23, 2007