Regarding hemi-section of the spinal cord, which of the following statements is false: loss of pain and temperature (pain & temp) on the contralateral site, loss of pain and temperature on the upper limb contralateral site, loss of ipsilateral weakness of the lower limb, or loss of ipsilateral joint position and vibration sense?

Brown-Séquard Syndrome: Clinical Manifestations of Spinal Cord Hemisection

The false statement regarding hemisection of the spinal cord is "Loss of pain & temp. on the upper limb contralateral site." In Brown-Séquard syndrome, pain and temperature sensation loss occurs on the contralateral side of the body beginning 2-3 segments below the level of injury, not specifically limited to the upper limb.

Pathophysiology of Spinal Cord Hemisection

Brown-Séquard syndrome results from hemisection (lateral half transection) of the spinal cord, causing a distinct pattern of neurological deficits due to interruption of specific ascending and descending tracts:

1. Ipsilateral manifestations (same side as the lesion):

   • Motor weakness/paralysis due to corticospinal tract damage
   • Loss of proprioception and vibration sense due to dorsal column damage
   • Loss of tactile discrimination

2. Contralateral manifestations (opposite side to the lesion):

   • Loss of pain and temperature sensation beginning 2-3 segments below the level of injury due to spinothalamic tract damage

Correct Clinical Manifestations

• Ipsilateral findings (same side as lesion):

  • Motor weakness/paralysis of the limbs below the lesion 1
  • Loss of joint position and vibration sense (proprioception) 2
  • Tactile discrimination impairment

• Contralateral findings (opposite side to lesion):

  • Loss of pain and temperature sensation beginning 2-3 segments below the level of injury 1, 2

Why "Loss of pain & temp. on the upper limb contralateral site" is False

This statement is incorrect because:

1. In a spinal cord hemisection, contralateral loss of pain and temperature occurs at levels below the lesion (not specifically in the upper limb)

2. If the hemisection occurs in the thoracic or lumbar region, the upper limbs would not be affected on either side

3. If the hemisection occurs in the cervical region, the upper limb on the same side as the lesion would have motor weakness, while the contralateral upper limb would have pain and temperature loss only at and below the level of the lesion

Clinical Assessment of Brown-Séquard Syndrome

When evaluating a patient with suspected spinal cord hemisection:

• Motor function: Assess for ipsilateral weakness/paralysis below the level of injury
• Sensory function:
  • Test proprioception and vibration sense (impaired ipsilaterally)
  • Test pain and temperature sensation (impaired contralaterally)
• Reflexes: Check for hyperreflexia and positive Babinski sign ipsilaterally

Diagnostic Approach

MRI of the spine without contrast is the first-line imaging modality for evaluating spinal cord hemisection 3. This allows visualization of the extent of the lesion and any associated pathology.

Common Pitfalls in Assessment

1. Pure Brown-Séquard syndrome is rare - Most cases present as Brown-Séquard-plus syndrome with incomplete manifestations

2. Level-dependent manifestations - The specific pattern of deficits depends on the level of the hemisection

3. Confusing ipsilateral vs. contralateral deficits - Remember that motor and proprioceptive deficits are ipsilateral, while pain and temperature deficits are contralateral

4. Overlooking autonomic dysfunction - Bowel and bladder dysfunction may occur with severe cervical or thoracic hemisection 3

By understanding the correct pattern of neurological deficits in Brown-Séquard syndrome, clinicians can accurately diagnose this condition and distinguish it from other spinal cord syndromes.