There are seven cervical, twelve thoracic, five lumbar, and one sacral vertebrae that make up the spine. The bones get progressively thicker moving down the spinal cord. The level of injury references Spinal Cord Injuries.
Cervical Injuries are the highest these injuries are referred to as C2 being the highest level of injury and C8 being the lowest level of injury with the most function. Individuals with Cervical injuries are most often referred to as Quadraplegics because all four limbs are affected.
Individuals with injuries below the cervical level of the spine are called thoracic injuries and are most often referred to as Paraplegics. Injuries to the thoracic levels relate to the trunk of the body. Paraplegics have complete use of their hands and arms, which indicates that only two limbs are affected. Thoracic injuries are injuries at or below the first thoracic vertebrae. These injuries are classified as T1 being the highest and T12 the lowest.
Individuals with injuries to the Lumbar section of the spine are not as common as injuries to the Cervical and Thoracic areas of the spinal cord. These injuries are referenced as L1 through L5.
Keep in mind that spinal cord injuries are referenced as complete and incomplete. In a complete spinal cord injury communication is stopped, whereas an incomplete injury leaves some nerve function in tact.