What is the difference between paraplegia and tetraplegia?

The main difference between paraplegia and tetraplegia (also known as quadriplegia) lies in which parts of your body are affected, which is determined by the neurological level of your spinal cord injury—the specific point on the spinal cord where normal function stops ^[1]. In short, tetraplegia can affect all four limbs (arms and legs) and the trunk, while paraplegia primarily affects the lower half of the body (legs and sometimes the lower trunk) with arm function generally spared ^{[1] [2]}. Neither term describes a single, absolute outcome; they describe a broad pattern of impairment, and exactly how much function is affected varies widely from person to person ^[1].

Vertebral Bones vs. Neurological Level

It is important to understand the difference between the bone that was broken and the actual damage to the nerve pathways. While doctors use imaging (like X-rays or MRIs) to see vertebral (bone) damage, the labels paraplegia and tetraplegia are based on the neurological level of injury ^[3]. This level is determined through a physical examination that tests exactly which muscles and areas of skin still have normal function ^[3].

Tetraplegia (Quadriplegia)

Tetraplegia refers to a pattern of weakness or paralysis that involves all four limbs as well as the torso (trunk) ^[2]. The terms tetraplegia and quadriplegia mean the exact same thing in medicine.

• Injury Location: Tetraplegia is caused by damage to the cervical spinal cord, which is the section located in your neck ^[1].
• What it may affect: It can affect the arms, hands, trunk, legs, and pelvic organs (bladder, bowel, and sexual function) ^{[1] [4]}. High cervical injuries can also impair breathing and respiratory muscles ^[5].

Paraplegia

Paraplegia refers to a pattern of impairment that primarily affects the lower half of the body, including both legs and possibly parts of the trunk ^[1].

• Injury Location: Paraplegia happens when the neurological injury is below the neck—in the thoracic (upper and middle back), lumbar (lower back), or sacral (tailbone) sections of the spinal cord ^[1].
• What it may affect: It primarily affects the legs, lower trunk, and pelvic organs ^{[1] [4]}. Upper body, arm, and hand function are generally spared ^[1].

Comparison Table

Complete vs. Incomplete Injuries

Neither paraplegia nor tetraplegia automatically means a total loss of movement or feeling. Your care team will classify your injury as “complete” or “incomplete” using a formal clinical examination called the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) ^[3]. This exam results in an ASIA Impairment Scale (AIS) grade (A through E), which helps standardize how injuries are described ^[3].

• Sacral Sparing: An injury is considered “incomplete” if there is preserved sensation or voluntary movement in the very lowest part of the spinal cord ^[7]. These lowest nerve pathways are called the sacral segments, which control the anal area; having function here is known as sacral sparing ^[7].
• Complete Injuries (AIS A): A “complete” injury means there is no sacral sparing ^[7]. However, complete does not mean the spinal cord is cut entirely in half, nor does it mean absolute paralysis of every muscle below the injury. Even with an AIS A complete injury, many people retain zones of partial preservation, meaning they have scattered patches of feeling or movement below their neurological level ^[3].
• What this means for you: Because injuries can be incomplete, someone with tetraplegia might still have some ability to move their arms, or even walk ^[2]. These labels do not guarantee a specific outcome for independence, wheelchair use, or walking ability ^[2].

When to Seek Urgent Care

Because high spinal cord injuries can affect the muscles used for breathing and coughing, it is critical to monitor your respiratory health ^[5]. If you experience new or worsening breathing difficulty, a weakened ability to cough, or sudden changes in your neurological function (like new weakness or numbness), seek urgent medical attention.