Handbook of diseases of the ear : for the use of students and practitioners / by Richard Lake.

Date:
1904
Catalogue details

Licence: In copyright

Credit: Handbook of diseases of the ear : for the use of students and practitioners / by Richard Lake. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    A BRIEF DESCRIPTION OF THE MORE IMPORTANT ANATOMICAL POINTS The External Ear, or Pinna, is formed of a fibro-cartilage, thrown into folds of considerable irregularity in different persons, which folds are intended to deflect the sound- waves towards the external meatus. The small portion of cartilage in front of the external meatus, known as the tragus, has for its principal function that, of preventing sound-waves thus deflected from being lost. The pinna is covered with skin and subcutaneous tissue, and at its centre is folded upon itself, but the edges do not come into close apposition, a cleft being left in its upper part which is closed by fibrous tissues. A cartilaginous tube is thus formed, which is attached to a roughened surface on the outer part of the temporal bone, and forms the outermost portion of the external auditory canal or meatus. The auditory or external meatus, a cartilaginous and bony tube, is about inches long ; its external or cartilaginous portion has an approximate length of | inch, on the an- terior aspect of which are two vertical clefts in the car- tilage, known as the fissures of Santorini. The inner or bony part of the canal, which averages in the adult h inch in length, is continuous with the cartilaginous meatus, and closed at its inner extremity by the tympanic membrane ; I