Obex
The obex is the point in the human brain at which the fourth ventricle narrows to become the central canal of the spinal cord.
The obex occurs in the caudal medulla.
The decussation of sensory fibers happens at this point.Lesions at the location can result in obstructive hydrocephalus. The most common lesion at this location is a subependymoma, a benign tumor. Hemangioblastoma has been observed in this location.to test brain, lymph, and neuroendocrine tissues for the presence of the abnormal prion protein to diagnose wasting diseases like Chronic wasting disease in cervidae. Positive IHC findings in the obex is considered the gold standard.Additional images
