Which of the following spinal cord tracts is responsible for transmitting crude touch, pain, and temperature sensation from the contralateral side of the body?

Explanation

## Spinothalamic Tract: Function and Anatomy **Key Point:** The spinothalamic tract (also called the lateral spinothalamic tract) is the primary ascending pathway for crude touch, pain, and temperature sensation from the body to the thalamus and cerebral cortex. ### Tract Characteristics | Feature | Detail | |---------|--------| | **Sensory modalities** | Pain, temperature, crude touch | | **Decussation level** | Within 1–2 spinal segments of entry (in the spinal cord) | | **Crossed fibers** | Contralateral (opposite side) | | **Termination** | Ventral posterolateral (VPL) nucleus of thalamus | | **Pathway organization** | Lateral columns of spinal cord | | **Clinical sign** | Contralateral loss below the lesion level | **High-Yield:** The spinothalamic tract crosses within 1–2 segments of entry, making it different from the dorsal column tracts (fasciculus gracilis and cuneatus), which ascend ipsilaterally before crossing at the medulla. ### Why Spinothalamic and Not Dorsal Columns? - **Fasciculus gracilis & cuneatus** carry discriminative (fine) touch and proprioception, not crude touch or pain - **Dorsal spinocerebellar tract** carries unconscious proprioception to the cerebellum, not to the thalamus for conscious sensation - The spinothalamic tract is the sole pathway for pain and temperature to reach consciousness **Clinical Pearl:** A Brown-Séquard syndrome (hemisection of spinal cord) produces ipsilateral loss of fine touch and proprioception below the lesion (dorsal columns) but **contralateral loss of pain and temperature** one to two segments below the lesion (spinothalamic tract crosses early). **Mnemonic:** **STT = Spinothalamic Tract = Sensation (pain, Temp, Touch-crude)**