The spine is composed of 33 interlocking bones called vertebrae. The lumbosacral region of the spine (or lumbar spine) consists of 5 lumbar vertebrae and 5 sacral vertebrae. The sacral vertebrae, which are fused together, are called the sacrum.
A disc is located between each pair of lumbar vertebrae. The discs are capsules of connective tissue with a soft, jellylike center. The discs absorb shock and make the spine flexible. The bones of the sacrum are joined to one another and have no discs between them.
The vertebrae are supported by ropy tissues called ligaments and groups of muscles:
The spinal cord runs through the spinal canal, a tunnel that is formed by the holes in the center of each of the vertebrae. Nerves branch from the spinal cord, pass through openings (foraminae) between the vertebrae, and branch to the lower body.
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical Reviewer Robert B. Keller, MD - Orthopedics
Current as ofJune 4, 2014
Current as of: June 4, 2014
Author: Healthwise Staff
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