Tetraplegia is a form of paralysis affecting all four limbs and the torso. The condition results from damage to the cervical region of the spinal cord, located in the neck. This damage disrupts the communication pathways between the brain and the rest of the body, leading to a loss of motor and sensory function below the site of the injury. The terms tetraplegia and quadriplegia are used interchangeably, as “tetra” is Greek for four and “quad” is the Latin equivalent.
Affected Body Functions
The most apparent effect of tetraplegia is the loss of voluntary muscle control in the arms, hands, legs, and feet. The disruption of nerve signals traveling through the spinal cord prevents the brain’s commands from reaching these muscle groups. This leads to an inability to perform movements that were once routine.
Sensation is also impacted. Individuals may experience a partial or total loss of the ability to feel touch, pressure, temperature, and pain in the affected areas of the body. This loss of sensory feedback means the brain no longer receives critical information from the skin and muscles below the injury level. This can create risks, as the person may not be aware of injuries or pressure sores developing.
The autonomic nervous system, which manages involuntary bodily processes, is also affected. This can lead to difficulties with bladder and bowel control, as the muscles that manage these functions are no longer under consistent regulation. Breathing can be compromised, sometimes necessitating mechanical ventilation, especially with injuries higher in the neck. Other autonomic challenges include regulating blood pressure, controlling body temperature, and impacts on sexual function.
Levels of Injury and Function
The extent of paralysis in tetraplegia is directly related to the location and severity of the injury along the seven cervical vertebrae (C1-C7). Injuries are classified as “complete” or “incomplete.” A complete injury results in a total loss of all sensory and motor function below the level of the lesion.
An incomplete injury means that some nerve pathways remain intact, allowing a person to retain some sensation or have limited muscle control in certain areas below the injury site. Approximately one-third of traumatic spinal cord injuries result in incomplete tetraplegia. The potential for recovery of function is greater with an incomplete injury.
The specific vertebra where the damage occurs determines the functional outcome. An injury at the C1 or C2 level, the highest vertebrae in the neck, is the most severe and often affects the muscles that control breathing, requiring immediate ventilatory support. An injury lower down, for example at the C7 level, may allow for more function, potentially preserving some movement in the arms and hands while still impacting the legs and torso.
Common Causes of Tetraplegia
Traumatic spinal cord injuries are the most frequent cause of tetraplegia. Major causes include motor vehicle accidents, significant falls, and injuries sustained during sports activities. Acts of violence, such as gunshot wounds that affect the cervical spine, can also lead to this type of paralysis.
The condition does not always stem from a traumatic event. Several non-traumatic medical issues can also cause damage to the spinal cord or brain, resulting in tetraplegia. Diseases such as transverse myelitis, which involves inflammation of the spinal cord, can disrupt nerve signals. Other conditions like multiple sclerosis, cerebral palsy, or a tumor pressing on the spinal cord can also cause the condition, as can a stroke affecting a specific part of the brain or brainstem.