INTRODUCTION TO EAR DISEASE: THE ANATOMY AND PHYSIOLOGY OF THE EAR INTRODUCTION
The ear is the human organ of hearing and balance. It has three parts, namely the outer ear, the middle ear and the inner ear. The outer ear consists of the visible external ear (otherwise called the pinna or the auricle) and the passage leading from this to the eardrum-the ear canal. The middle ear is bounded externally by the eardrum (properly called the tympanic membrane). It is a cavity within the temporal bone, which is a part of the skull. It contains three tiny bones which transmit sound to the inner ear, and one or two other structures of importance. The inner ear contains the organs of hearing and balance, and is buried within very dense bone which serves to protect it against (most) injuries. The organ of hearing is named the cochlea and the organs of balance are collectively called the vestibular system. Figure 1 shows a schematic representation of the general plan of the ear. The individual parts
will now be described in a little more detail to enable the reader to understand the medical discussions in later chapters.