Spine 101 – Overview of All Things Spine

The spine consists of 33 bones and provides support for the body, so if you suffer from back pain, it is important for the doctor—and you—to know what part of your back is affected. This “Spine 101” will explain the basics of your spinal anatomy and how it functions, so you can have a better idea of your diagnosis and how it may affect your mobility.

Spinal Anatomy

The spine consists of three sections: the cervical spine, thoracic spine, and lumbar spine. These correspond to the neck, mid-to upper back, and lower back, respectively. The cervical spine contains seven vertebrae, while there are 12 vertebrae in the thoracic spine and five vertebrae in the lumbar spine.

Each vertebra is an individual bone, placed one on top of another. Between each vertebra is an intervertebral disk made of cartilage which aids in shock absorption and allows flexibility. Disks consist of a tough out shell and a jelly-like interior.

Each vertebra also has four facet joints, with two connecting to the vertebra above and two connecting to the vertebra below. These joints permit the back to move.

The sacrum connects the spine to the iliac—or hip—bones. The coccyx, or tailbone, consists of four fused bones which allow ligaments and muscles to connect to the pelvic floor.

The Spinal Cord

Within the spinal column lies the spinal cord, which along with the brain serves as the body’s central nervous system. The spinal cord sends messages to the brain, which then relays those messages to other parts of the body.

The spinal cord itself forms a tube running about 18 inches from the brain stem to the end of the spinal column. As with the brain, the spinal cord is covered with three membranes called meninges—the pia, arachnoid, and dura.

Nerves, Ligaments, and Muscles

The primary muscle groups in the spine are the extensors and flexors, which allow flexing and the ability to pick up objects. They are also responsible for spinal stabilization. Ligaments hold the vertebrae in place, and also provide disk protection.

The peripheral nervous system is the nerve network emanating from both sides of the spinal cord via through passages between the vertebra on the spinal canal. These are the nerves, spreading throughout the body, that send signals from the spinal cord and brain back and forth between different areas of the body.

Some nerves, known as the cauda equina, reach beyond the spinal cord into the tailbone and send nerve commands into the legs. Spinal nerves are numbered based on their vertebrae, with the cervical nerves known as C1 through C8, the thoracic nerves labeled as T1 to T12 and the lumbar nerves listed as L1 to L5. There are five sacral spine nerves—S1 to S5—and one nerve in the coccyx.

The Most Common Sites for Pain and Injuries

Even though the thoracic spine has more vertebrae than the lumbar or cervical spine, spinal injuries and back pain are actually least likely to result from this area. The lumbar region is responsible for most cases of low back pain, primarily due to amount of wear-and-tear it experiences over an individual’s lifetime. Most of the spine’s weight is concentrated in the lumbar region.

Talk to a Spine Doctor Today

If you are experiencing back problems, call us today and arrange an appointment. An experienced spinal surgeon with our practice could consult with us regarding your condition, conduct a thorough medical examination, and make a recommendation for an appropriate course of treatment.