In this article. Font Size. A. A. A. Spinal stenosis is the narrowing of spaces in the spine (backbone) which causes pressure on the spinal cord and nerves. About 75% of cases of spinal stenosis occur in the low back (lumbar spine).  The nerves that branch off your spinal cord down your back and neck are called lower motor neurons. These nerves exit between each of your vertebrae and go to all parts of your body. Any damage to the spinal cord can result in a loss of sensory and motor function below the level of injury. For example, an injury to the thoracic or lumbar area may cause motor and sensory loss of the legs and trunk (called paraplegia). (figure 2.5, & 10). In the lumbar spine, the vertebral canal houses an extension of the spinal cord known as the thecal sac (aka, dural sac), which in turn houses the nerves (lumbar spinal nerves) that give life to the lower extremities, pelvis, and lower abdomen. It extends from the conus medullaris down to the second sacral segment (S2).  The Spinal Cord. The Spinal Cord is connected to the brain and is about the diameter of a human finger. From the brain the spinal cord descends down the middle of the back and is surrounded and protected by the bony vertebral column. Both the nerves and the segments in the spinal cord are numbered in a similar way to the vertebrae. The point at which the spinal cord ends is called the conus medullaris, and is the terminal end of the spinal cord. It occurs near lumbar nerves L1 and L2. The human vertebral column is the vertebral column (backbone or spine) of the human skeleton, consisting of 24 articulating vertebrae and 9 fused vertebrae in the sacrum and the coccyx. The vertebrae in the column are separated from each other by intervertebral discs. These regions are called the cervical spine, thoracic spine, lumbar spine, sacrum and coccyx. There are a total of 33 vertebrae in the vertebral column. The articulating vertebrae are named according to their region of the spine. The spinal cord is the most important structure between the body and the brain. The spinal cord extends from the foramen magnum where it is continuous with the medulla to the level of the first or second lumbar vertebrae. It is a vital link between the brain and the body, and from the body to the brain. The spinal cord is 40 to 50 cm long and 1 cm to 1.5 cm in diameter The vertebral column (also known as the backbone or the spine), is a column of approximately 33 small bones, called vertebrae. The column runs from the cranium to the apex of the coccyx, on the posterior aspect of the body. It contains and protects the spinal cord.  The human vertebral column consists of 33 vertebrae. These are divided into different regions, which correspond to the curves of the spinal column. These regions are called the cervical spine, thoracic spine, lumbar spine, sacrum and coccyx. There are a total of 33 vertebrae in the vertebral column. The articulating vertebrae are named according to their region of the spine. There are seven cervical vertebrae, twelve thoracic vertebrae and five lumbar vertebrae The spine is also designed to protect your spinal cord. The spinal cord is a column of nerves that connects your brain with the rest of your body, allowing you to control your movements. Without a spinal cord, you could not move any part of your body, and your organs could not function. This is why keeping your spine healthy is vital if you want to live an active life. This is why damage to the spinal cord can cause paralysis in certain areas and not others -- it depends on which spinal nerves are affected. The nerves of the cervical spine go to the upper chest and arms. The nerves in your thoracic spine go to your chest and abdomen. The lumbar vertebrae consist of five individual cylindrical bones that form the spine in the lower back. These vertebrae carry all of the upper body’s weight while providing flexibility and movement to the trunk region. They also protect the delicate spinal cord and nerves within their vertebral canal. Found along the body’s midline in the lumbar (lower back) region, the lumbar vertebrae make up the region of the spine inferior to the thoracic vertebrae in the thorax and superior to the sacrum and coccyx in the pelvis....
http://www.webmd.com/back-pain/guide/spinal-stenosis https://mayfieldclinic.com/PE-AnatSpine.htm http://www.chirogeek.com/Anatomy%20Page/disc-anatomy.html http://cnsvp.stanford.edu/atlas/spinal_cord1/ https://en.wikipedia.org/wiki/Human_vertebral_column http://neuroscience.uth.tmc.edu/s2/chapter03.html http://teachmeanatomy.info/back/bones/vertebral-column/ https://en.wikipedia.org/wiki/Human_vertebral_column http://umm.edu/programs/spine/health/guides/anatomy-and-function http://www.innerbody.com/anatomy/skeletal/lumbar-vertebrae-lateral
why does the human spinal cord endat lumbar vertebra