About 10 years ago, the so-called chronic cerebrospinal venous insufficiency syndrome was discovered. This clinical
entity, which is associated with extracranial venous abnormalities that impair venous outflow from the brain, was initially
found exclusively in multiple sclerosis patients. Currently, we know that such venous lesions can also be revealed in other
neurological pathologies, including Alzheimer’s and Parkinson’s diseases. Although direct causative role of chronic cerebrospinal
venous insufficiency in these neurological diseases still remains elusive, in this paper, we suggest that perhaps an abnormal
venous drainage of the brain affects functioning of the glymphatic system, which in turn results in the accumulation of
pathological proteins in the cerebral tissue (such as β-synuclein, β-amyloid and α-synuclein) and triggers the venous outflow
from the cranial cavity and circulation of the cerebrospinal fluid in the settings of neurodegenerative disease.