Where does the spinothalamic tract decussate?

Where does the spinothalamic tract decussate?

• A. In the thalamus.
• B. At or near its entry level in the spinal cord.
• C. In the medulla.
• D. Spinothalamic never decussates.

Answer: (B)

The spinothalamic tract carries pain and temperature. After the sensory neuron enters the spinal cord, it synapses in the dorsal horn, and the second-order neuron crosses to the opposite side at or near the level of entry through the anterior white commissure. The tract then ascends on the contralateral side to the thalamus and onward to the cortex. So the decussation happens right where the fibers enter the spinal cord, not in the thalamus or medulla, and it does cross.

The spinothalamic tract carries pain and temperature. After the sensory neuron enters the spinal cord, it synapses in the dorsal horn, and the second-order neuron crosses to the opposite side at or near the level of entry through the anterior white commissure. The tract then ascends on the contralateral side to the thalamus and onward to the cortex. So the decussation happens right where the fibers enter the spinal cord, not in the thalamus or medulla, and it does cross.