The head and speculum of an otoscope have been designed for irrigating and draining secretions from the external auditory canal. The instrument is illustrated in the accompanying sketch.
The fluid used for irrigating is delivered by gravity through the intake tube A, B, C. A is the connection over which the rubber tubing from the reservoir fits; B is an adjustable valve regulating the rate of flow, and C is the inner opening of the tube near N, the beginning of the spiral grooves on the inner surface of the speculum to deliver the fluid in a circular motion at the opening of the speculum.
Washings are removed through the drainage tube J, K, L, M. M is the opening of the drainage tube, L is an oval opening in the head of the otoscope by which the drainage tube J, K, L, M can