Spinal Cord Tracts Quiz

Spinal Cord Structure and Function

• The spinal cord has sensory tracts on one half and motor tracts on the other half, but all tracts are present on both sides.
• The precise location and size of the tracts change throughout different levels of the spinal cord.
• The name of a tract often indicates its location in the white matter and where it begins and ends.

Functions of the Spinal Cord

• The white matter of the spinal cord contains sensory and motor tracts, which are the "highways" for conduction of sensory nerve impulses toward the brain and motor nerve impulses from the brain toward effector tissues.
• The spinal cord gray matter is a site for integration (summing) of excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs).

Tracts in the Spinal Cord

• Posterior column: Gracile fasciculus and Cuneate fasciculus
• Lateral corticospinal tract, Posterior spinocerebellar tract, and Anterior spinocerebellar tract
• Rubrospinal tract, Lateral reticulospinal tract, and Lateral spinothalamic tract
• Spinal nerve, Vestibulospinal tract, Anterior spinothalamic tract, and Medial reticulospinal tract
• Tectospinal tract and Anterior corticospinal tract
• The spinothalamic tract originates in the spinal cord and ends in the thalamus, and it is a sensory tract.

Effects of Spinal Cord Injuries

• The closer the injury is to the head, the greater the area of the body that may be affected.
• Muscle functions retained at progressively lower levels of spinal cord transection:
  • C1-C3: no function maintained from the neck down; ventilator needed for breathing
  • C4-C5: diaphragm, which allows breathing
  • C6-C7: some arm and chest muscles, which allows feeding, some dressing, and manual wheelchair required
  • T1-L1: progressively more functions regained with lower levels of injury
• Traumatic injuries to the spinal cord can result in a range of outcomes, from little or no long-term neurological deficits to severe deficits and even death.
• Brown-Séquard syndrome occurs when damage to the posterior column and lateral corticospinal tract results in loss of proprioception and fine touch sensations on the ipsilateral side, and ipsilateral paralysis.