Neuroanatomy • lesion localization

Spinal cord, sliced open.

Pick a lesion. The tract map lights up, then read the deficit by side and level. Think in pathways, not memorized syndromes.

Axial cross-section · patient’s right is on your left
CST CST SPINOTH. SPINOTH. DC DC ANTERIOR / VENTRAL POSTERIOR / DORSAL PATIENT RIGHT PATIENT LEFT
Dorsal columns · vibration / proprioception
Lateral spinothalamic · pain / temperature
Lateral corticospinal · UMN motor
Gray matter / other tracts
Selected pattern

What gets hit

The three rules that localize it
DCMLAscends ipsilaterally in the cord; crosses in the medulla.
SpinothalamicCrosses in the cord via the anterior white commissure, usually within 1–2 segments.
Lateral CSTAlready crossed in the pyramidal decussation; cord lesion causes ipsilateral UMN weakness below.

Orientation: the left side of the drawing is the patient’s right. “At level” means segmental gray matter/root findings; “below” means long-tract findings.

High-yield nuance: a hemicord lesion produces contralateral pain/temperature loss beginning slightly below the lesion, while dorsal-column and CST deficits begin at the lesion level and stay ipsilateral.