Therefore, a hemi-section lesion to the spinal cord will demonstrate loss of these modalities on the contralateral side of the lesion, while preserving them on the ipsilateral side. Upon touching this side, the patient will not be able to localize where they were touched, only that they were touched. This is because fine touch fibers are carried in the dorsal column-medial lemniscus pathway. The fibers in this pathway decussate at the level of the medulla. Therefore, a hemi-section lesion of the spinal cord will demonstrate loss of fine touch on ipsilateral side (preserved on the contralateral side) and crude touch (destruction of the decussated spinothalamic fibers from the contralateral side) on the contralateral side.Pure Brown-Séquard syndrome is associated with the following:
Interruption of the lateral corticospinal tracts:
Ipsilateral spastic paralysis below the level of the lesion
Babinski sign ipsilateral to lesion
Abnormal reflexes and Babinski sign may not be present in acute injury
Interruption of posterior white column:
Ipsilateral loss of tactile discrimination, vibratory, and position sensation below the level of the lesion
Interruption of lateral spinothalamic tracts:
Contralateral loss of pain and temperature sensation. This usually occurs 2–3 segments below the level of the lesion. Treatment
Treatment is directed at the pathology causing the paralysis. If the syndrome is caused by a spinal fracture, this should be identified and treated appropriately. Although steroids may be used to decrease cord swelling and inflammation, the usual therapy for spinal cord injury is expectant.
Pathophysiology
The hemisection of the cord results in a lesion of each of the three main neural systems:
the principal upper motor neuron pathway of the corticospinal tract
one or both dorsal columns
the spinothalamic tractAs a result of the injury to these three main brain pathways the patient will present with three lesions:

The corticospinal lesion produces spastic paralysis on the same side of the body below the level of the lesion (due to loss of moderation by the UMN). At the level of the lesion, there will be flaccid paralysis of the muscles supplied by the nerve of that level (since lower motor neurons are affected at the level of the lesion). The lesion to fasciculus gracilis or fasciculus cuneatus (dorsal column) results in ipsilateral loss of vibration and proprioception (position sense) as well as loss of all sensation of fine touch. The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion.In addition, if the lesion occurs above T1 of the spinal cord it will produce ipsilateral Horners syndrome with involvement of the oculosympathetic pathway. Diagnosis
Magnetic resonance imaging (MRI) is the imaging of choice in spinal cord lesions.Brown-Séquard syndrome is an incomplete spinal cord lesion characterized by findings on clinical examination which reflect hemisection of the spinal cord (cutting the spinal cord in half on one or the other side).