Bell's Palsy Essay

The immunological hypothesis was introduced by McGovern and coworkers.35-36 Friedreich hypothesized that the cause of facial paralysis was ~rheumatic" because of exposure to cold often followed by fever, chills and local pain and swelling in and around the neck.37 Brunninghausen speculated that the paralysis arose from the nerve sheath becoming thickened and compressed in stylomastoid foramen. The cold hypothesis, or paralysis e frigore, maintained that exposure to draughts produced the palsy. Exposure to cold or drafts considered as the primary cause of Bell's palsy. Cobb and Coggeshall38 hypothesized:-Edema of a nerve trunk may interrupt passage of the nerve impulses along axons, especially if the oedema happens to be a point at which the nerve is passing through a bony canal (Stylomastoid foramen in case of facial nerve). Exposure of the face to severe cold, a strong wind or local cooling often brings on edema that blocks the foramen, presses on the facial nerve and causes paralysis- so called Bell's palsy. Newman, and Bohn39 and Kovocs40 have stated that over 75% of all cases with spontaneous onset are due to refrigeration or exposure. In 1972 McCormick published his hypothesis suggesting that …show more content…
With in the axoplasm, there are neurofilaments and microtubules which are involved in axona transport mechanism. The diameter of facial nerve axon varies between 3 and 20un and the nodes of spaced from 0.1 to 1.8mm apart. As the facial nerve fibers are myelinated, the salutatory conduction takes place in it which accounts for the rapid conduction velocity of the facial never, which is 70 to 110./sec. When injury to the neuron results in demyelination and faulty remyelination of the nerve fiber, the myelin covering is thinner and the distance between the nodes of ranvier are are altered, leading to marked slowing in the conduction velocity as well as to an increase in the threshold for