Discogenic Low Back Pain
By Stan Andrzejewski • January 27th, 2006 • 7807 Views
Anatomy of the Spine.
A basic vertebra is comprised of a bony block and a bony ring. The block is sandwiched between disks. The ring houses the precious spinal cord. The ring consists of 2 pedicles, 2 lamina, 1 spinous process, and 2 transverse processes. Processes are levers that attach to muscles. Each vertebra has 4 facets [joints], 2 superior, 2 inferior attached on the lateral posterior side of the vertebral body. A thoracic vertebra has 4 more facets attaching to the ribs. Facets are the synovial joints of the spine. This means they have a synovial membrane that secretes synovial fluid, and a capsular ligament that holds the synovial fluid. The angle of orientation of the facets changes with each vertebra. The angle influences the direction of movement.
The spine is segmental, consisting of 7 cervical, 12 thoracic, 5 lumbar, 5 sacral [fused], and 4 coccygeal [fused] vertebras. We must consider that each vertebrae has any direction of movement. The image of vertebra floating in all directions is useful. We categorize each vertebra movement as flexion, extension, rotation, and side bending. Some vertebras move less, some more. This is called the relative flexibilities/inflexibilities of the spine.
Lumbar vertebras are massive for weight bearing. The facets have a sagittal orientation allowing little rotation, but a lot of flexion, extension.
Thoracic vertebras are medium size with ribs attached. Ribs are the armor of our vital organs. We have 4 more facets per vertebrae. These are more facets to become hypomobile and restrict spinal movement. The spinous processes are sharply angled down to prevent excessive back-bending.
Cervical vertebras are the smallest, designed for mobility of our head. Facets are angled at 45 degrees from the horizontal.
Spinal ligaments allow efficient passive joint stabilization. They limit and direct vertebral movement. These ligaments have many pain receptors. The anterior longitudinal ligament [ALL] is thin stretching from the occiput to the sacrum. The ALL stretches with backbends. The posterior longitudinal ligament [PLL] is thick, but tapers from the lumbar to the sacrum. The PLL stretches in forward bends. There many more spinal ligaments connecting vertebras to each other in every imaginable direction....