You’ve seen it in the q-bank: a trauma vignette, a spinal cord lesion level, and five answer choices that all sound plausible under pressure. Anterior cord syndrome is one of those diagnoses where getting the right answer is less about memorizing a name and more about mapping tracts to deficits—and then using that map to eliminate distractors with confidence.
Tag: Neurology > Peripheral Nerve & Spinal Cord
The Clinical Vignette (Q-bank style)
A 28-year-old man is brought to the ED after a high-speed MVC. He has midline cervical tenderness. On exam, he has bilateral weakness in the upper and lower extremities. He cannot feel pinprick or temperature below the level of injury. Vibration and proprioception are intact. Reflexes are decreased initially. MRI shows a lesion involving the anterior two-thirds of the spinal cord.
Question: Which spinal cord syndrome best explains these findings?
The Correct Answer: Anterior Cord Syndrome
Why it fits
Anterior cord syndrome classically results from damage to the anterior two-thirds of the cord, often due to:
- Anterior spinal artery infarct (ischemia)
- Flexion injuries and vertebral body fractures
- Severe hypotension in watershed areas
Tracts affected (and what you lose)
| Structure (cord) | Modality | Deficit in anterior cord syndrome? |
|---|---|---|
| Corticospinal tracts (lateral) | Motor | Yes → bilateral weakness below lesion |
| Spinothalamic tracts (anterolateral) | Pain & temperature | Yes → bilateral loss below lesion |
| Dorsal columns (posterior) | Vibration, proprioception | No → spared |
High-yield pearl: The dorsal columns are supplied primarily by the posterior spinal arteries, so they’re often spared in anterior spinal artery pathology.
What about reflexes?
Early after acute spinal cord injury, patients can have spinal shock:
- Flaccid weakness
- Hyporeflexia
- Autonomic dysfunction
Later, as spinal shock resolves: - Hyperreflexia
- Spasticity
- Babinski sign
How to Systematically Kill the Distractors
Below are the common answer choices that try to steal points—plus the one-liner that should pop into your head when you see them.
Distractor 1: Central Cord Syndrome
Why it’s tempting
It often shows up in trauma vignettes and involves cervical cord injury.
Why it’s wrong here
Central cord syndrome causes:
- Upper extremity weakness > lower extremity weakness (hands are hit hardest)
- Variable sensory loss
- Often due to hyperextension injury, especially in older patients with cervical spondylosis
Key difference: In anterior cord syndrome, motor and pain/temp loss are typically more complete and bilateral below the lesion with dorsal column sparing. In central cord, the hallmark is arm > leg weakness, not a clean dissociation of pain/temp with preserved vibration/proprioception.
High-yield association: Central cord can produce a “cape-like” pain/temp loss if the lesion affects crossing fibers in the anterior white commissure (classically also discussed with syringomyelia).
Distractor 2: Brown-Séquard Syndrome (Hemisection)
Why it’s tempting
Students remember it’s all about tract anatomy—same as anterior cord.
Why it’s wrong here
Brown-Séquard is asymmetric. Findings below the lesion:
- Ipsilateral motor weakness (corticospinal)
- Ipsilateral loss of vibration/proprioception (dorsal column)
- Contralateral loss of pain/temp beginning a few levels below (spinothalamic)
Your vignette is bilateral motor loss + bilateral pain/temp loss with preserved vibration/proprioception—that’s not a hemisection pattern.
High-yield association: Think penetrating trauma (e.g., stab wound).
Distractor 3: Posterior Cord Syndrome
Why it’s tempting
Because it’s essentially the “opposite” of anterior cord and can be confused when you’re rushing.
Why it’s wrong here
Posterior cord syndrome causes loss of:
- Vibration and proprioception
- Sensory ataxia, positive Romberg
But pain and temperature are preserved, and motor function is often relatively spared.
Your vignette specifically says vibration/proprioception intact and pain/temp lost → that points away from posterior cord.
High-yield association: Neurosyphilis (tabes dorsalis) and B12 deficiency affect dorsal columns (technically subacute combined degeneration hits dorsal columns + corticospinal, but pain/temp are relatively spared).
Distractor 4: Cauda Equina Syndrome
Why it’s tempting
It’s a high-yield emergency with weakness and sensory symptoms.
Why it’s wrong here
Cauda equina is a peripheral nerve (LMN) problem, not a spinal cord tract syndrome. Classic features:
- Severe radicular pain
- Areflexia
- Saddle anesthesia
- Bowel/bladder dysfunction
- Often asymmetric weakness and sensory loss
Anterior cord syndrome is an UMN lesion below the level (after spinal shock resolves) and shows tract-pattern sensory loss (pain/temp) with dorsal column sparing.
Test-taking clue: If the stem is emphasizing “below the lesion” with clear tract dissociation, think spinal cord—not cauda equina.
Distractor 5: Conus Medullaris Syndrome
Why it’s tempting
It overlaps with cauda equina and involves bowel/bladder dysfunction.
Why it’s wrong here
Conus medullaris lesions (around L1) typically cause:
- Early bladder/bowel dysfunction
- Saddle anesthesia
- Mixed UMN/LMN findings
- Often more symmetric than cauda equina
But it doesn’t give you the classic anterior cord tract pattern of:
- bilateral motor loss + bilateral pain/temp loss
- preserved vibration/proprioception
If the vignette is built around dissociated sensory loss (pain/temp gone, proprioception intact), conus/cauda choices are usually decoys.
The “Tract Map” You Should Visualize in 5 Seconds
Anterior cord syndrome = “AMPS”
- Anterior cord
- Motor loss (corticospinal)
- Pain & temperature loss (spinothalamic)
- Sparing of dorsal columns (vibration/proprioception)
Extra High-Yield Facts (USMLE-friendly)
1) Vascular supply is the story
- Anterior spinal artery supplies the anterior two-thirds:
- corticospinal + spinothalamic + anterior horn cells
- Posterior spinal arteries supply dorsal columns
Classic board phrasing: “Loss of pain and temperature with preserved vibration/proprioception” → think anterior spinal artery.
2) Anterior horn involvement can add LMN signs at the level
If the lesion hits anterior horn cells, you can see LMN signs at the lesion level (e.g., focal weakness, atrophy), with UMN signs below (after spinal shock resolves).
3) Spinothalamic crossing explains bilateral pain/temp loss
Pain/temp fibers:
- enter cord
- travel up/down ~1–2 levels in Lissauer tract
- cross via anterior white commissure
So a cord lesion can produce pain/temp loss starting slightly below the lesion.
4) Don’t forget autonomics
Anterior cord injuries can be associated with:
- hypotension/bradycardia (neurogenic shock, especially cervical/high thoracic)
- bladder dysfunction depending on level/severity
Rapid-Fire Differentials Table (Best for Last-Minute Review)
| Syndrome | Motor | Pain/Temp | Vibration/Proprioception | Signature clue |
|---|---|---|---|---|
| Anterior cord | ↓ bilateral | ↓ bilateral | Preserved | ASA infarct / flexion injury |
| Central cord | Arms > legs | Variable | Variable | Hyperextension in older pt |
| Brown-Séquard | ↓ ipsi | ↓ contra | ↓ ipsi | Hemisection, penetrating trauma |
| Posterior cord | Usually ok | Preserved | ↓ | Sensory ataxia, +Romberg |
| Conus medullaris | Mixed | Saddle | Variable | Early bowel/bladder, symmetric |
| Cauda equina | LMN, asymmetric | Patchy | Patchy | Radicular pain, areflexia |
Takeaway: Why Every Answer Choice Matters
If you can name anterior cord syndrome, great—but points come from proving it by:
- identifying the tracts affected,
- recognizing what’s spared, and
- using those specifics to eliminate close distractors (especially central cord and Brown-Séquard).
On test day, your best friend is the pattern: motor + pain/temp loss with dorsal column sparing → anterior cord syndrome.