Anatomy of the Spine
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The vertebral column is also called the spinal column or backbone. It's made up of 33 vertebrae that are separated by spongy disks and classified into 4 distinct areas. The cervical area consists of 7 bones in the neck. The first cervical vertebra supports the skull. The thoracic spine consists of 12 bones in the back area; the lumbar spine consists of 5bones in the lower back area; 5 sacral bones; and 4 coccygeal bones (the number of coccygeal bones can vary from 5 to 3).
Disks between each vertebrae help absorb shock. By adulthood, the 5 sacral vertebrae fuse to form 1 bone, and the 4 coccygeal vertebrae fuse to form 1 bone.
The spinal cord is a bundle of nerves. It passes through the center of the vertebral column. The spine protects the spinal cord and allows nerves for your arms, legs, and organs to exit and enter at each level.