Spinal Cord Syndromes
Overview
The spinal cord contains discrete laminated sensory and motor tracts. Partial cord lesions produce predictable, topographically precise deficits based on which tracts are compromised, enabling lesion localisation on clinical examination correlated by MRI.
Key Spinal Tracts
- Dorsal Columns (Gracile + Cuneate fasciculi): Vibration, proprioception, fine touch. Ascend IPSILATERALLY and cross in the medulla. Ipsilateral loss below the lesion.
- Lateral Corticospinal Tract: Motor pathway. Crosses in the medulla. IPSILATERAL UMN weakness below the lesion.
- Lateral Spinothalamic Tract: Pain and temperature. Crosses within 1-2 segments of entry at the anterior commissure. CONTRALATERAL pain/temperature loss 1-2 levels below the lesion.
Classic Incomplete Cord Syndromes
- Brown-Sequard Syndrome (Hemisection): Ipsilateral UMN paralysis + ipsilateral dorsal column loss. Contralateral pain/temperature loss. Classic: penetrating stab wound.
- Central Cord Syndrome: Bilateral spinothalamic disruption at the crossing (anterior commissure). 'Cape-like' bilateral pain/temperature loss over shoulders and arms. Motor and fine touch mostly preserved. Classic: elderly hyperextension injury on spondylotic cord.
- Anterior Cord Syndrome (ASA Infarction): Bilateral motor paralysis + bilateral loss of pain/temperature. Dorsal columns PRESERVED (intact proprioception and vibration). Classic: acute aortic surgery, watershed ischaemia.
WarningSubacute Combined Degeneration of Cord
Vitamin B12 deficiency simultaneously destroys the dorsal columns (loss of vibration/proprioception) and lateral corticospinal tracts (UMN signs + positive Babinski). MRI shows T2 hyperintensity in the posterior and lateral cord columns on sagittal STIR.
High Yield Facts
LightbulbFRCR / MD Prep Pearl
MRI T2/STIR hyperintensity within the cord locates the lesion. Gadolinium enhancement = active inflammation (MS plaque, NMOSD). DWI restriction = cord infarction (acute). STIR is the most sensitive sequence detecting cord oedema. Look for 'snakeeye' appearance on axial T2 in central cord syndrome.