In
anatomy, 'lumbar' is an
adjective that means ''of or pertaining to the
abdominal segment of the
torso, between the
diaphragm and the
sacrum (
pelvis)''. The five
vertebrae in the lumbar region of the back are the largest and strongest in the
spinal column. In most
mammals, the lumbar region of the spine curves outward; this is called
lordosis.
The actual
spinal cord terminates between vertebra one and two of this series, called L1 and L2. The
nervous tissue that extends below this point are individual strands that collectively form the
cauda equina. In between each lumbar vertebra a
nerve root exits, and these nerve roots come together again to form the largest single nerve in the
human body, the
sciatic nerve. The sciatic nerve runs through the back of each leg and into the feet. This is why a disorder of the low back that affects a nerve root, such as a
spinal disc herniation, can cause pain that radiates along the sciatic nerve (
sciatica) down into the foot.
There are several
muscles in the low back that assist with rotation, flexibility and strength. These muscles are susceptible to injury, especially while lifting heavy objects, or lifting while twisting. A low back
muscle strain can be extremely painful but will usually heal within a few days or weeks.
The lumbar portion of the spine bears the most body weight and also provides the most flexibility, a combination that makes it susceptible to injury and wear and tear over time. This is why low back pain is so prevalent.
See also
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Car seat and lumbar support
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Low back pain
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Lumbar Puncture
External links
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Back Pain Medical Journal for Patients
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Lower back pain information