Spinal cord
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The spinal cord is a part of the vertebrate central nervous system that is enclosed in and protected by the vertebral column (it passes through the spinal canal). It consists of nerve cells. The cord conveys the 31 spinal nerve pairs of the peripheral nervous system, as well as central nervous system pathways that innervate skeletal muscles.
The vertebral column consists of vertebrae described as belonging to 5 groups. These groups are (in order from top to bottom): the cervical, thoracic, and lumbar vertebrae, and the sacrum and coccyx.
Injury
Spinal cord injuries are caused by damage to the spinal cord, such as falling on the neck or back, or having the spinal cord moved or disrupted in another way. The vertebral bones or intervertebral disks can shatter, causing the spinal cord to be punctured by a sharp fragment of bone. Usually victims of spinal cord injuries will suffer loss of feeling in certain parts of their body. In good cases a victim might only suffer loss of hand or foot function. More severe injury may result in paraplegia, tetraplegia, or full body paralysis below the site of injury to the spinal cord.
The two most common areas of the spinal cord most injured are the cervical spine (C1-C7) and the lumbar spine (L1-L5). (The notation C1, C7, L1, L5 refer to the location of a specefic vertebra in either the cervical, thoracic, or lumbar region of the spine.)
Embryology
In the human fetus, the spinal cord extends all the way down to the sacral vertebrae. As a person matures, the rest of the body grows faster than the spinal cord, so that adulthood, the spinal cord reaches only to the level of the first or second lumbar vertebrae. Below this level, there is no spinal cord, only spinal nerves that form the cauda equina.
External links
- [Spinal cord, topographical and functional anatomy. Spinal cord cross-section, detailed anatomy]
- [Nerve Structures of the Spine]
- BrainMaps at UCDavis []
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