QS Study

Effects of Hemisection of Spinal Cord

Hemisection of the spinal cord results in the typical syndrome of ipsilateral paralysis and contralateral pain and temperature loss below the level of the lesion, known as the Brown-Séquard syndrome. It is caused by a lateral hemisection of the spinal cord that severs the pyramidal tract, the uncrossed dorsal columns, and the crossed spinothalamic tract. Major Causes are; Penetrating Trauma, Blunt spinal cord injury, Disc Herniation, Epidural Hematoma etc.

Below the level of Section

 (A) Same side:

Sensory changes:

  • Kinesthetic and position sensation are cost due to damage of tract of Goll and Burdach.
  • Pain temperature and Crude touch remain unchanged.

Motor changes:

  • Extensive paralysis of the upper motor neuron type due to damage of crossed pyramidal tract.
  • Temporary loss of vasomotor tone.

(B) Opposite side:

Sensory changes:

  • Complete loss of pain, temperature, and crude touch due to damage of spinothalamic tract.
  • Kinesthetic sensation, fine touch etc will persist.

Motor Changes:

  • Either no paralysis or paralysis of few muscles only.

At the level of Section

 (A) Same side:

Sensory changes: Complete anesthetics due to damage of posterior nerve root and posterior horn cells.

Motor changes:

  • Lower motor neuron type paralysis due to the destruction of anterior horn cells.
  • Complete and permanent vasomotor paralysis the destruction of lateral horn cells.

(B) Opposite side:

Sensory changes: Some loss of pain sensation due to the destruction of crossed horizontal spinothalamic fibers.

Motor changes: Nil or very slight.

Above the level of Section

(A) Same side: Hyperaesthesia due to irritation of uppercut ends of the damaged fibers.

(B) Opposite side: Hyperaesthesia may be referred.

Additional Effect for Specific Region

At cervical region:

Three additional features –

  • Construction of the pupil on the same side,
  • Loss of biceps triceps, supinator and pronator jerks,
  • Paralysis of the same side at the diaphragm.

At lumbar region

If 3rd and 4th lumber involve feature will be –