There are 31 pairs of spinal nerves: 8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
Because of the large number of nerve roots needed to control the upper and lower extrem-ities, the spinal canal in the cervical and lumbar regions is larger than in the thoracic region.
Although there are seven cervical vertebrae, there are actually eight cervical nerve roots. The first cervical nerve root exits between the skull (C0) and C1. the 8th cervical nerve root exits at the same level as the corresponding vertebrae. For example, the L1 nerve root exits between L1 and L2.The nerve roots branch off the spinal cord higher than their actual exit through the inter-vertebral foramen. This means that the spinal nerves must often pass downwards adjacent to the spinal cord before exiting through the intervertebral forament. This leaves the nerves exposed to risk of compression by protruding disc material. Therefore, it is possible to have a compression of the L5 nerve root at the L4-L5 disc space.
Reference: www.iscoliosis.com, www.brainspine.com.hk
The information provided aims to provide educational purpose, if you have the described conditions as above, please consult your neurosurgeon.
