Spinothalamic Tract (Anterolateral System) - The Pain and Temperature Pathway

The spinothalamic tract is the major ascending sensory pathway transmitting pain, temperature, crude touch and itch from the body to the brain. After entering the spinal cord, sensory fibers synapse in the posterior horn and the second-order neurons cross within one to two spinal segments through the anterior white commissure before ascending contralaterally to the VPL nucleus of the thalamus and then to the primary somatosensory cortex. Lesions of this tract produce contralateral loss of pain and temperature sensation below the level of injury. It is one of the body's essential protective pathways, enabling rapid perception of potentially harmful stimuli.