Jerry Haney, SCI Series, Spinal Cord Purpose

I sincerely hope the information presented will be useful and help you and yours cope with this devastating injury.

If you do not find a subject shown here, please let me know and I will certainly try to research the information and present it on this website in continuing updates.

This important section is devoted to spinal cord injury, and includes information about the actual spinal cord injury, the changes that take place in the body, the spinal cord and what it does, the spinal column, differences in the type of spinal cord injury, the recovery process and terminology used when discussing SCI.

The spinal cord is the communicating link between the spinal nerves and the brain. The nerves that lie only within the spinal cord itself are called upper motor neurons (UMNs). These run only between the brain and the spinal nerves. The spinal nerves branch out from the spinal cord into the tissues of your body. Spinal nerves are also called lower motor neurons (LMNs). (See figure)

In movement, the brain sends messages through the spinal cord (UMNs) to the spinal nerves (LMINs). The LMINs then carry these messages to the muscles to coordinate complicated movements such as walking. In this way, the brain can influence movement.

In sensation, information is collected by the LMINs and sent up the spinal cord to the brain. This allows conscious awareness of feelings such as heat or cold.

You may wonder how the spinal cord keeps these messages from getting confused, what with all the running back and forth between brain and body. The LMINs and the UMNs carry messages in different nerve fibers.

Within the cord itself, the UMIN nerve fibers are combined into spinal tracts. Each tract carries messages one way, either up or down. They are similar to the lanes on a freeway. (See figure)

What Is an LMN and What Does it Do? Each LMN, or spinal nerve, has two main parts: One part carries information related to movement from the spinal cord to the muscles, It is called the motor portion of the nerve. Each motor portion of a spinal nerve connects to a specific muscle group. Each level of the spinal cord causes movement in a corresponding group of muscles.

The other part of the LMN carries messages of feeling, such as heat and cold, from the body to the spinal cord, It is called the sensory portion of the nerve.

Different types of sensation or feeling are carried up the spinal cord to the brain. These include pain, touch, heat, cold, vibration, pressure, and knowing where a body part is located in space without looking at it.

Each sensory portion of the spinal nerve collects information about feelings from a given area of skin. Each area is called a dermatome and matches a specific spinal cord level..