Spinal Cord Tracts (NEET PG Focus)
Mastering the location and decussation of spinal tracts is essential for localizing lesions (Brown-Séquard, Syringomyelia, etc.).
1. Major Ascending (Sensory) Tracts
| Tract | Modality | Decussation |
|---|---|---|
| Dorsal Column | Fine touch, Vibration, Proprioception | Medulla |
| Lateral Spinothalamic | Pain, Temperature | Spinal Cord (within 1–2 segments) |
2. Descending (Motor) Tracts
- Lateral Corticospinal Tract: Controls voluntary movement of limbs. Decussates at the Pyramidal decussation (medulla).
3. Clinical Correlations
- Brown-Séquard Syndrome (Hemisection): Contralateral loss of pain/temp (spinothalamic) and ipsilateral loss of proprioception/motor (dorsal column/corticospinal).
- Syringomyelia: Bilateral loss of pain/temp in a “cape-like” distribution (damage to the anterior white commissure).
NEET PG Hint: Remember that the dorsal column fibers ascend ipsilaterally and only cross in the medulla, while the spinothalamic tract fibers cross immediately upon entering the spinal cord. This is the key to answering lesion questions correctly.