The Auricula or Pinna is of an ovoid form, with its larger end directed upward. Its lateral surface is irregularly concave, directed slightly forward, and presents numerous eminences and depressions to which names have been assigned. The prominent rim of the auricula is called the helix; where the helix turns downward behind, a small tubercle, the auricular tubercle
The lobule, composed of tough areolar and adipose tissues, and wanting the firmness and elasticity of the rest of the auricula
The middle ear or tympanic cavity is an irregular, laterally compressed space within the temporal bone. It is filled with air, which is conveyed to it from the nasal part of the pharynx through the auditory tube. It contains a chain of movable bones, which connect its lateral to its medial wall, and serve to convey the vibrations communicated to the tympanic membrane across the cavity to the internal ear.
The internal ear is the essential part of the organ of hearing, receiving the ultimate distribution of the auditory nerve. It is called the labyrinth, from the complexity of its shape, and consists of two parts: the osseous labyrinth, a series of cavities within the petrous part of the temporal bone, and the membranous labyrinth, a series of communicating membranous sacs and ducts, contained withi
n the bony 
cavities.
(Interior of right osseous labyrinth)
The Osseous Labyrinth (labyrinthus osseus)-The osseous labyrinth consists of three parts: the vestibule, semicircular canals, and cochlea. These are cavities hollowed out of the substance of the bone, and lined by periosteum; they contain a clear fluid, the perilymph, in which the membranous labyrinth is situated.
The Vestibule (vestibulum).—The vestibule is the central part of the osseous labyrinth, and is situated medial to the tympanic cavity, behind the cochlea, and in front of the semicircular canals. It is somewhat ovoid in shape, but flattened transversely
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