The second cervical vertebra is called the Axis, upon which Atlas pivots. The first cervical vertebra, upon which the head is perched is sometimes called Atlas, after the Greek mythological figure who held up earth. The back of the head is called the Occiput. The first and second cervical segments are special because they hold and pivot the head. The L5 root exits the cord between L1 and S1 bodies. The L1 root exits the spinal cord between L1 and L2 bodies. The T12 root exits the spinal cord between T1 and L1.
![spine definition spine definition](https://i.ytimg.com/vi/ipelCshahvc/maxresdefault.jpg)
The first thoracic root or T1 exits the spinal cord between T1 and T2 vertebral bodies. The spinal roots for C2 exit the spinal column at the atlanto-axis. The spinal roots for C1 exit the spinal column at the atlanto-occiput junction. The sacral cord is situated between the T12 to L2 vertebrae, as shown in figure 1 Spinal Roots. The lumbar cord is situated between T9 and T11 vertebrae. For example, the C8 cord segment is situated in the C7 vertebra while the T12 cord is situated in the T8 vertebra. Spinal cord segmental levels are defined by their roots but are not always situated at the corresponding vertebral levels. The spinal cord sends roots that exit the spinal canal between vertebral bodies. There are 7 cervical (neck), 12 thoracic (chest), 5 lumbar (back), and 5 sacral (tail) vertebrae. The vertebral levels are indicated on the left side while the cord segmental levels are listed for the cervical (red), thoracic (green), lumbar (blue), and sacral (yellow) cord. As shown in the figure to the left (adapted from a spinal anatomy web site at Emory University) the spinal cord segmental levels do not necessarily correspond to the bony segments. The spinal cord itself has “neurological” segmental levels which are defined by the spinal roots that enter and exist the spinal column between each of the vertebral segments.
#Spine definition series#
The spine consists of a series of vertebral segments. The spinal cord is situated within the spine. In this article, I will try to explain the currently accepted definitions of spinal cord injury levels and classification.Īnd vertebral levels.
![spine definition spine definition](https://karmanhealth-karmanhealthcare.netdna-ssl.com/wp-content/uploads/2013/07/spinal.jpg)
Doctors frequently had different definitions of spinal cord injury levels and complete and incomplete injuries. What is the meaning of the different spinal cord injury levels, the definition of complete and incomplete injury, and the different classification of spinal cord injury? In the early 1990’s, there was no single definition of level, completeness of injury, or classification. They may also be told that they are classified according to the American Spinal Injury Association (ASIA) Classification, as a ASIA A, B, C, D, or E. They can sometimes be told that they have a bony fracture or other involvement of one or more spinal vertebral levels. They are often told that the injury is “complete” or “incomplete”.
![spine definition spine definition](https://healthncare.info/wp-content/uploads/2017/01/Sacralization.jpg)
People with spinal cord injury are often told that they have an injury at a given spinal cord level. Keck Center for Collaborative Neuroscience