Spinal Cord Injury Levels: A Complete Overview of Each Type – Flint Rehab

The level of a spinal cord injury refers to the lowest region of the spinal cord where normal motor control and sensation exist. Knowing ones level of injury will help individuals determine what functions may be affected after an injury.

To help you understand each of the spinal cord injury levels, this article will discuss:

The spinal cord is the neural passageway that allows for communication between the brain and body. After a spinal cord injury, that connection is disrupted, and areas below the level of injury may no longer effectively send or receive communication from the brain.

The spinal cord in particular is essential for the functions of movement and sensation. As such, common complications of spinal cord injury involve paralysis and/or changes in sensation, such as numbness.

To determine which secondary effects may occur, it is essential to understand your level of spinal cord injury.

When determining your level of injury, a physician will test your sensory and motor functions using the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), also called the ASIA exam.

Each level of the spinal cord sends motor signals from the brain to different muscles throughout the body. The muscles designated to each level of the spinal cord are called myotomes.

Additionally, each level of the spinal cord receives sensory information from a different area of skin called a dermatome. This information travels through the spinal cord to the brain for processing and to allow the brain to decide how to appropriately respond.

In the next section, youll learn more about how different spinal cord injury levels affect different dermatomes and myotomes and, as a result, affect sensation and movement. Before we get there, lets discuss the anatomy of the spinal column.

The spinal cord is protected by the spine, which is composed of 33 vertebrae. Spinal nerves branch out from the spinal cord and exit above or below their corresponding vertebrae.

For each spinal cord level, there is a pair of spinal nerves (31 pairs in total), with one nerve going to the left side of the body and one going to the right. Furthermore, each spinal nerve contains a sensory nerve root that sends messages from the body to the brain, and a motor nerve root that sends messages from the brain to the corresponding area of the body.

Additionally, the spinal cord is divided into 5 regions (from top to bottom):

Motor signals from the brain and sensory signals from the body cannot travel past damaged regions of the spinal cord. As a result, all motor functions and sensations innervated below the level of injury may be affected, depending on the severity of the injury.

If the spinal cord was completely severed, its called a complete spinal cord injury; and if some connections within the spinal cord were left intact, its called an incomplete spinal cord injury. The higher your level of injury and the more complete the spinal cord injury, the more functions will be affected.

In the next section, well go over what functions are affected at each of the spinal cord injury levels.

The cervical region of the spinal cord consists of 7 vertebrae and 8 cervical nerve roots in the neck area. Cervical spinal cord injuries are the most prevalent, making up nearly60% of all SCIs. They are also generally the most debilitating because the entire body can potentially be affected.

Completecervical spinal cord injuriesresult inquadriplegia, which describes paralysis in both the upper and lower limbs.

Here are the functions that correspond with each specific level of cervical spinal cord injury:

Learn more about cervical spinal cord injuries

Below the cervical region is the thoracic region of the spinal cord. This region of the spinal cord consists of 12 levels.

Thoracic-level spinal cord injuriesprimarily affect sensation in the trunk and abdomen, as well as the muscles that make up your trunk and chest. As a result, individuals may experience difficulties with balance, posture, breathing, and coughing.Thoracic spinal cord injuries may also affect innervation of important organs, including the lungs, heart, liver, and small intestine.

Because the thoracic region is located below the cervical region, all functions corresponding to the cervical region remain intact. Therefore, individuals with SCIs below the T1 level should be able to use their hands and arms normally.

The lowermost functions left intact at each level of thoracic spinal cord injury include:

Learn more about thoracic spinal cord injuries

Following the thoracic region is the lumbar region. This region of the spinal cord consists of 5 levels.

Lumbar spinal cord injuriesonly affect the lower body, so individuals should have unaffected motor control and sensation in their hands, arms, and trunk. Because individuals with lumbar spinal cord injuries experience weakness or paralysis in their legs, they may struggle with walking and balance.

The lowermost functions left intact at each level of the lumbar spinal cord injury include:

Learn more about lumbar spinal cord injuries

The sacral region of the spinal cord consists of 5 levels. Individuals with sacral-level spinal cord injuries have unaffected upper body functions and partial leg functions.

Because bowel and bladder functions are innervated by the bottommost segments of the sacral spinal cord, individuals with nearly any level of spinal cord injury are likely to experience bowel and bladder problems.

The functions left intact at each level of the sacral region of the spinal cord include:

At the very end of the spinal cord is a single coccygeal nerve. This nerve innervates the skin around the tailbone. As a result, individuals may experience pain, discomfort, or complete loss of sensation in the tailbone area.

However, because this nerve makes up the lowest level of the spinal cord, individuals should have normal motor control and sensation throughout most of their bodies.

Functional loss after spinal cord injury depends on the severity and level of injury. The severity of your SCI will determine to what extent functions innervated below your level of injury are affected. Likewise, the level of injury will determine which functions may or may not be affected.

We hope this article helped you better understand spinal cord injury levels and what sensorimotor functions may be impacted.

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Spinal Cord Injury Levels: A Complete Overview of Each Type - Flint Rehab