The condition described is Anterior Cord Syndrome — but let me clarify precisely, because the pattern you described (intact touch + pain, lost motor, ipsilateral) requires careful anatomical reasoning. Let me explain fully:
The Answer: This Does NOT Fit a Classic Syndrome — Here's Why
The combination you describe is:
- Touch sensation: INTACT (same side)
- Pain sensation: INTACT (same side)
- Motor function: LOST (same side — ipsilateral)
This pattern is neuroanatomically unique and points to an isolated corticospinal tract (motor) lesion sparing the sensory tracts. Here is how the spinal cord tracts map:
| Tract | Location in Cord | Function | Decussation |
|---|
| Corticospinal (lateral) | Lateral column | Motor | Already crossed in medulla (ipsilateral in cord) |
| Dorsal columns | Posterior column | Fine touch, proprioception, vibration | Cross in medulla |
| Spinothalamic | Anterior/lateral column | Pain & temperature | Cross within 1-2 levels of entry (contralateral in cord) |
Closest Matching Syndrome: Anterior Cord Syndrome (partial match)
Anterior Cord Syndrome causes:
- ❌ Motor loss (bilateral or unilateral)
- ❌ Pain & temperature loss
- ✅ Preserved dorsal column function (fine touch, proprioception)
This does NOT fully match because pain is preserved in your scenario.
Best Match: Isolated Corticospinal Tract Lesion / Pure Motor Hemiplegia
The exact pattern — ipsilateral motor loss with preserved ipsilateral touch AND pain — is best explained by:
Pure Motor Hemiplegia (Lacunar Infarct)
- A small infarct in the posterior limb of the internal capsule or basis pontis (corticospinal fibers only)
- Affects motor fibers exclusively
- All sensory modalities (touch, pain, proprioception) are completely spared
- Upper + lower limb same side involved (face may also be involved)
This is one of the classic lacunar syndromes described by C. Miller Fisher.
Why Not Brown-Séquard?
Brown-Séquard (hemi-cord transection) gives:
| Finding | Side |
|---|
| Motor loss | Ipsilateral ✓ |
| Fine touch/proprioception loss | Ipsilateral |
| Pain & temperature loss | Contralateral ✗ |
So in Brown-Séquard, pain sensation is lost on the opposite side, not preserved ipsilaterally — ruling it out here.
Summary
The condition is Pure Motor Hemiplegia, most commonly due to a lacunar infarct at:
- Posterior limb of the internal capsule
- Basis pontis
The lesion selectively involves the corticospinal tract after it has already crossed, producing ipsilateral (same-side) weakness of upper and lower limbs, with complete preservation of all sensory modalities including both touch and pain on that side.
(Spine Injury Best Practices, p. 35)