Etymology: L, crena, notch. the formation of notches or leaflike scalloped edges on an object. Red blood cells exposed to a hypertonic saline solution acquire a notched, shriveled surface as a result of the osmotic effect of the solution. They are then called crenated red blood cells. crenate, crenated, adj.
Occipital neuralgia is the neck/head pain that results from injury or irritation to the occipital nerves. It can be caused by trauma, such as a car accident, by a pinched nerve root in the neck (from arthritis, for example) or by âtightâ muscles at the back of the head that entrap the nerves.
Causes of Ocular Migraines. Some scientists think that ocular (visual) migraines are caused by or triggered by inflammatory substances released in the tissues surrounding the circulatory and nerve system of the head and brain. Ocular migraines may be due to stress and fatigue - the same probable causes of migraine headaches.