Learn About The Spine
Spine Anatomy
The spinal column is one of the primary support structures in the human skeleton. Your spine is made up of a column of vertically stacked bones, called vertebrae, which surround and protect the spinal cord. There are 33 separate vertebrae that are divided into five segments: cervical, thoracic, lumbar, sacral and coccyx. Each of the vertebra lines up much like blocks on top of one other. There are discs between each vertebra, which act as shock absorbers between each bony vertebra. The vertebrae, while interconnected, operate relatively independently, which gives your back a degree of flexibility while enabling it to provide a tremendous amount of support.
The Five Segments of the Spine
The Nervous System
Running down the spine, and protected by the vertebra, are some of the most important components of the human body's nervous system. In particular, the spinal cord is protected by an opening in the back of the vertebrae called the foramen. Other nerves extend from the spinal cord through spaces between each vertebra.
The Disc
In between the vertebrae are the discs. The discs act as a cushion between the vertebral bones. Each disc consists of a soft jelly-like center and a tough outer material that holds the disc's shape and position in the spine.
The Facets
On the back of the vertebrae are two sets of facets; one set at the top of the vertebra (called the "superior facets") and one set at the bottom (called the "inferior facets"). The superior facets face up and make contact with the downward facing inferior facets on the next vertebra forming the facet joint. The facet joints are the points at which two vertebrae contact each other. The facet joints act as a hinge on which two vertebrae move when bending forward and backward.
The Ligaments, Tendons and Muscles
A variety of soft tissue holds the entire spinal column in place and allows it to flex. Ligaments and tendons are fibrous bands of tissue that attach to bone. Ligaments connect two or more vertebrae and help stabilize the spine. Tendons attach muscle to bone allowing the spine to move when the muscles contract and relax.