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).
Hwang W, Ralph J, Marco E, Hemphill JC (June 2003). "Incomplete Brown-Séquard syndrome after methamphetamine injection into the neck". Neurology. 60 (12): 2015–16. doi:10.1212/01.wnl.0000068014.89207.99. PMID 12821761. S2CID 13491137. Kraus JA, Stüper BK, Berlit P (1998). "Multiple sclerosis presenting with a Brown-Séquard syndrome". J. Neurol. Sci. 156 (1): 112–13. doi:10.1016/S0022-510X(98)00016-1. PMID 9559998. S2CID 44403915. Lim E, Wong YS, Lo YL, Lim SH (April 2003). "Traumatic atypical Brown-Sequard syndrome: case report and literature review". Clin Neurol Neurosurg. 105 (2): 143–45. doi:10.1016/S0303-8467(03)00009-X. PMID 12691810. S2CID 37419566. Lipper MH, Goldstein JH, Do HM (August 1998). "Brown-Séquard syndrome of the cervical spinal cord after chiropractic manipulation". AJNR Am J Neuroradiol. 19 (7): 1349–52. PMID 9726481. Mastronardi L, Ruggeri A (January 2004). "Cervical disc herniation producing Brown-Sequard syndrome: case report". Spine. 29 (2): E28–31. doi:10.1097/01.BRS.0000105984.62308.F6. PMID 14722422. S2CID 36231998. Miyake S, Tamaki N, Nagashima T, Kurata H, Eguchi T, Kimura H (February 1998). "Idiopathic spinal cord herniation. Report of two cases and review of the literature". J. Neurosurg. 88 (2): 331–35. doi:10.3171/jns.1998.88.2.0331. PMID 9452246. Rumana CS, Baskin DS (April 1996). "Brown-Sequard syndrome produced by cervical disc herniation: case report and literature review". Surg Neurol. 45 (4): 359–61. doi:10.1016/0090-3019(95)00412-2. PMID 8607086. Stephen AB, Stevens K, Craigen MA, Kerslake RW (October 1997). "Brown-Séquard syndrome due to traumatic brachial plexus root avulsion". Injury. 28 (8): 557–58. doi:10.1016/S0020-1383(97)83474-2. PMID 9616398. External links

Case studies of Brown-Séquard syndrome