. Anatomy, descriptive and applied. Anatomy. THJ<: EXTERNAL EAR 1123 the tympanic plate, which, in the fetus, exists as a separate ring ( tijin- panicus), incomplete at its upper part. (See Section on Osteology, p. 87.) The skin lining the meatus is very thin, adheres closely to the cartilaginous and osseous portions of the tube, and covers the surface of the membrana tympani, forming a very thin outer layer. After maceration the thin pouch of epidermis, when withdrawn, preserves the form of the canal. In the thick subcutaneous tissue of the cartilaginous part of the meatus are nu
. Anatomy, descriptive and applied. Anatomy. THJ<: EXTERNAL EAR 1123 the tympanic plate, which, in the fetus, exists as a separate ring ( tijin- panicus), incomplete at its upper part. (See Section on Osteology, p. 87.) The skin lining the meatus is very thin, adheres closely to the cartilaginous and osseous portions of the tube, and covers the surface of the membrana tympani, forming a very thin outer layer. After maceration the thin pouch of epidermis, when withdrawn, preserves the form of the canal. In the thick subcutaneous tissue of the cartilaginous part of the meatus are numerous ceruminous glands (glandulae ceruminosae) which secrete the ear ivax or ceruvien. They resemble in structure sweat glands, and their ducts open on the surface of the -Vertical section through the external auditory canal and tympanum, passing i ovalis. (Testut.) , front of the fenestra Relations of the Canal.—In front of the osseous part is the glenoid fossa, which receives the condyle of the mandible (Fig. 100), which, however, is separated from the cartilaginous part by the retromandibular part of the parotid gland. The movements of the mandible influence to some extent the lumen of the cartilaginous portion. Behind tlie osseous part are the mastoid air cells {cellulae mastoideae), separated from it by a thin layer of bone (Fig. S4o). The arteries supplying the external canal are branches from the posterior am-iciilar, internal maxillary, and superficial temporal. The veins of the external canal accompany the corresponding arteries and pass to the in- ternal maxillary, temporal, and posterior auricular veins. The lymphatics accompany the veins and enter the parotid and posterior auricular lymph nodes. The nerves are chiefly derived from the auriculotemporal branch of the inferior maxillary nerve, the auricularis magnus, and the auricular branch of the vagus. The point of junction of the osseous and cartilaginous portions of the tube is an obtuse angle, which pr
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
