Conditions in Neurorehabilitation: Spinal Cord Injury and Disorders of the Motor Unit

Tetraplegia

Complete paralysis of all four extremities and trunk, including respiratory muscles, resulting from lesions involving the cervical spinal cord.

Paraplegia

Complete paralysis of all or part of the trunk and both lower extremities ($\text{LEs}$), resulting from damage to the thoracic or lumbar spinal cord or cauda equina.

Conus Medullaris

The tapered caudal termination of the spinal cord located approximately at the level of the $L1$ vertebra in adults.

Dorsal Column / Medial Lemniscus

Ascending pathway originating from first-order sensory neurons in the posterior root ganglion that conveys proprioception, vibratory sensation, deep touch, and discriminative touch.

Anterolateral System

Ascending sensory tract system composed of the spinothalamic, spinoreticular, and spinotectal tracts that transmits pain, temperature, and crude touch sensations.

Lateral Corticospinal Tract

Primary descending motor pathway responsible for voluntary movement and contralateral selective motor control, specifically governing skilled hand movements.

Rubrospinal Tract

Descending motor tract that originates in the red nucleus of the midbrain tegmentum and mediates motor control of the limbs.

Major Spinal Cord Tracts

The neuroanatomical organization of white matter tracts in the spinal cord, comprising ascending sensory pathways and descending motor pathways.

Neurological Level of Injury (NLI)

The most caudal segment of the spinal cord that demonstrates normal motor and normal sensory function on both the left and right sides of the body.

Motor Level vs. Sensory Level

Motor level is the most caudal segment with normal bilateral motor function; sensory level is the most caudal segment with normal bilateral sensory function.

Key Muscle Intactness Rule (ISNCSCI)

Standard defining a key muscle as having intact innervation if it scores at least $3/5$ on manual muscle testing and the next most rostral key muscle scores a normal $5/5$.

Dermatome

The area of the skin supplied by sensory fibers originating from a single spinal dorsal nerve root and its corresponding spinal nerve.

Dermatome Landmarks: $T4$ and $T10$

Key anatomical sensory landmarks located at the nipple line ($T4$) and at the umbilicus or belly button ($T10$).