Anatomy and physiology: the ear.

An appreciation of the physical behaviour of the ear cannot be complete without a knowledge of its physical structure, and the subjective interpretation of acoustical phenomena depends to a large extent on the initiation and communication of impulses along the neural pathway to and from the brain. It is therefore logical to commence discussion of the physics of the ear by a general descrip­ tion of its anatomical structure, which may be classified under the two headings of (1) the receiving and conducting mechanism, and (2) the perceptive, analytical and assessing system. The reception and conduction of sound is a mechanical process whereby the disturbances due to an incident sound excitation result in stimulation of the end organ of the neural pathway. From thence, along the course of the latter, nerve signals proceed to the section of the brain known as the auditory cortex, where the final assessment of the incident stimulation is made, and from whence information or instructions may be fed back to parts of the conductive mechanism, the end organ or other parts of the body with which the ear has neural connection.