Anatomy of Spine
The spine is divided into three major sections; each section is made up of individual bones called vertebrae.
- The Cervical Section (Neck). This section has seven(7) cervical vertebrae
- The Thoracic Section (Upper Back). This section has Twelve(12) thoracic vertebrae
- The Lumbar Spine Section (Lower Back). This section has five (5) lumbar vertebrae
- Sacral. Four fused bones forming the sacrum
- Coccyx. The tailbone
Beneath the Lumbar Spine is a bone called the Sacrum that is part of the pelvis.
An individual vertebra is made up of a number of parts. The body of the vertebra is the primary area of weight bearing and provides a resting place for the fibrous discs that separate each of the vertebrae. The lamina covers the spinal canal, the large hole in the center of the vertebra through which the spinal nerves pass. The spinous process is the bone you can feel when running your hands down your back.
The paired transverse processes are oriented 90 degrees to the spinous process and provide attachment for back muscles. There are four facet joints associated with each vertebra.
- A pair face upward
- Another pair faces downward.
These interlock with the adjacent vertebrae and provide stability to the spine.
Intervertebral discs that act as cushions between the bones separate the vertebrae. Each disc is made up of two parts.
- Annulus Fibrosus. The annulus fibrosus is the tough outer covering of the intervertebral disc.
- Nucleus Pulposus. Nucleus pulposus is the jelly-like substance in the middle of the spinal disc. It is the remnant of the notochord. It functions to distribute hydraulic pressure in all directions within the disc under compressive load.
Causes of Back Pain
Various structures in the spine can generate back pain, the reason can be:
- The large nerve roots that go to the legs and arms are irritated
- The smaller nerves that innervate the spine are irritated
- The large paired back muscles are strained
- The bones, ligaments or joints themselves are injured
- The disc space itself is a source of pain.