Spinal cord tracts and their decussation

What it is

The cord is gray matter around a central canal, set in white matter that holds the long tracts. The gray matter has a posterior horn, an anterior horn and an intermediate horn, and the intermediate horn is the sympathetic one, T1 to L2/L3. Three tracts do most of the work:

• Dorsal column, ascending: pressure, vibration, touch and proprioception. It is the fasciculus gracilis for the lower body and legs, and the fasciculus cuneatus for the upper body and arms.
• Corticospinal tract, descending: voluntary motor, the tract of fine movement. It runs as a lateral corticospinal tract and an anterior corticospinal tract.
• Spinothalamic tract, ascending: the lateral spinothalamic tract for pain and temperature, the anterior spinothalamic tract for crude touch and pressure.

The lateral corticospinal and the lateral spinothalamic tracts each hold sacral and cervical fibers. Drawn on the same view are the dorsal root, the anterior white comissure, the pyramidal tract and the spinocerebellar tract, with the anterior spinal artery in front and the posterior spinal arteries at the back.