Bell's palsy—facial nerve paralysis—has been defined as an ischemic palsy of the seventh cranial nerve. It is sympathetic paralysis, apparently due to a vasoconstriction of the arterioles of the peripheral perineural vascular channels of the seventh cranial nerve.1
There is usually a history of exposure to cold or draft on the affected side, although many patients will not recall such incidence of exposure.
It has been implied that a hyperactivity or activation of the sympathetic nervous system neuropathways will cause a vasoconstriction of the arterioles, which in many parts of the face will show no direct evidence of tissue involvement such as paleness of the underlying skin. If the small and none too plentiful arterioles of the seventh nerve are involved, the vasoconstriction will start a chain of events wherein ischemia, capillary dilatation, transudation, edema of the nerve and nerve sheath will occur, then associated loss of function, that
KIME CE. Bell's Palsy: A New Syndrome Associated with Treatment by Nicotinic Acid: A Guide to Adequate Medical Therapy. AMA Arch Otolaryngol. 1958;68(1):28–32. doi:10.1001/archotol.1958.00730020032004
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