[Blood supply of the ear and gravity]

The terminal circulation of the labyrinth is weak and slow. There is no musculature or vasomotor innervation in labyrinthine arterial vessels, which makes hardly feasible circulation control for therapeutic purposes. The rate of circulation in the labyrinth varies as a function of local pCO2 and is controlled by arteriolar-venular anastomoses. Labyrinthine circulation is also influenced by the gravitational field. This is especially true of man and his upright posture because changes in the spatial body position cause significant blood shifts. In the dependent segments of the body, the hydrostatic pressure of arterial and venous blood increases and intracapillary pressure grows. As a result, capillaries become enlarged inducing mixed-type hyperemia. Transcapillary filtration of plasma containing oxygen and trophic substances, including drugs, enhances. Under conditions of mixed, partially venous, hyperemia the number of functioning capillaries increases. In the cranial part, including the labyrinth, these reactions have a negative sign in the orthostatic position, and a positive sign in the antiorthostatic position. In order to increase the efficacy of innex ear treatment, we applied the method of therapeutic hyperemia. Patients were kept in a head-down position at -15 degrees for an hour and drugs were administered. This therapy proved effective in cases of sensory hypoacusis.