Question

Contralateral loss of pain and temperature is due to injury to:

• A. Anterior spinothalamic tract
• B. Lateral spinothalamic tract
• C. Fasciculus gracilis
• D. Fasciculus cuneatus

Answer 1

The Correct Option is B

To understand why a contralateral loss of pain and temperature is due to injury to the "Lateral spinothalamic tract," it's essential to know the functionality of the different tracts in the spinal cord:

• The Lateral spinothalamic tract is responsible for transmitting pain and temperature sensations from the body to the brain. When an injury occurs in this tract, it results in a loss of these sensations on the opposite side (contralateral) of the body.
• The Anterior spinothalamic tract carries crude touch and pressure sensations, not specifically pain and temperature.
• The Fasciculus gracilis and Fasciculus cuneatus are parts of the dorsal columns in the spinal cord and are involved in carrying fine touch, vibration, and proprioceptive information, not pain and temperature.

Therefore, an injury to the Lateral spinothalamic tract disrupts the transmission of pain and temperature signals, leading to contralateral loss of these sensations. This happens because the fibers in the Lateral spinothalamic tract cross over to the opposite side in the spinal cord shortly after entering, causing sensations from one side of the body to be processed on the opposite side of the brain.