Spinal Stenosis (Page 2)
Spinal stenosis can occur in a variety of ways in the spine. Approximately 75% of cases of spinal stenosis occur in the low back (lumbar spine), which is called lumbar spinal stenosis, and most will affect the sciatic nerve which runs along the back of the leg. When this happens, it is commonly called sciatica.
Spinal Anatomy and its Effects on Types of Spinal Stenosis
The vertebral column in the spine and sacrum (at the bottom of the spine) is like a stack of blocks that serve to support the structures of the body. Each of these bony structures has additional bony attachments that serve to help stabilize the spine and to protect the spinal cord or nerves passing downward from the brain to organs, muscles and sensory structures of the body. Each vertebral body and its attachments and the disc between the adjacent vertebrae are known as a spinal segment.
The entire length of the spinal column has a large central canal or passage through which the spinal cord descends, and holes to each side of the canal to allow emergence of spinal nerves at each level. The spinal cord stops at the upper part of the low back, and below that the tiny contained nerve rootlets descend loosely splayed out - like a horse’s tail – and are protectively enclosed in a long sack. All central nerve structures are protected further by membranes, with a tough outer membrane called the dura (tough) mater (mother).
