The spinal cord is the major collection of nerves that communicate muscle movement and sensation
to and from the brain and the rest of the body. It is surrounded by a column of bony rings called
vertebrae. The nerves that travel from the brain to the tailbone, together with this column of bones
is called the spine.
An injury to the spine may cause the bones around the spinal cord to break and press against the
spinal cord, which can damage the nerves, breaking the communication path and affecting
movement and sensation.
In addition to movement and sensation, the spinal cord carries nerves signals that affect and control
other body systems such as skin, bowel, bladder, and breathing. So, damage to the spinal cord,
depending on the completeness of the injury, may cause these body functions not to work the same
The American Spinal Injury Association (ASIA) ﬁrst published an international classiﬁcation of spinal cord injury in 1982, called the International Standards for Neurological and Functional Classiﬁcation of Spinal Cord Injury. Now in its sixth edition, the International Standards for Neurological Classiﬁcation of Spinal Cord Injury (ISNCSCI) is still widely used to document sensory and motor impairments following SCI. It is based on neurological responses, touch and pinprick sensations tested in each dermatome, and strength of the muscles that control ten key motions on both sides of the body, including hip ﬂexion (L2), shoulder shrug (C4), elbow ﬂexion (C5), wrist extension (C6), and elbow extension (C7).[Traumatic spinal cord injury is classiﬁed into ﬁve categories on the ASIA Impairment Scale:
• A indicates a “complete” spinal cord injury where no motor or sensory function is preserved
in the sacral segments S4-S5.
• B indicates an “incomplete” spinal cord injury where sensory but not motor function is
preserved below the neurological level and includes the sacral segments S4-S5. This is
typically a transient phase and if the person recovers any motor function below the
neurological level, that person essentially becomes a motor incomplete, i.e. ASIA C or D.
• C indicates an “incomplete” spinal cord injury where motor function is preserved below the
neurological level and fewer than half of key muscles below the neurological level have a
muscle grade of 3 or more (active movement with full range of motion against gravity).
• D indicates an “incomplete” spinal cord injury where motor function is preserved below the
neurological level and at least half of the key muscles below the neurological level have a
muscle grade of 3 or more.
• E indicates “normal” where motor and sensory scores are normal. It is possible to have
spinal cord injury and neurological deﬁcits with completely normal motor and sensory