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Full text of "Diseases Of The Nose Throat And Ear"

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J. R. McCallum


The pharynx is a fibromuscular tube lined with epithelium. It extends from the
base of the skull superiorly to the level of the sixth cervical vertebra where it
becomes continuous with the oesophagus (Fig. 46). Anteriorly it communicates
with the nasal cavities, the mouth and the larynx, and is thus divided anatomic-
ally into the nasopharynx, oropharynx and laryngopharynx (hypopharynx).
The lining epithelium is of the stratified squamous type, except in the naso-
pharynx where columnar ciliated epithelium is found. There are numerous
mucous glands. The middle fibrous tissue layer consists of the pharyngobasilar
fascia. The outer muscular layer comprises chiefly the three constrictor
muscles, superior, middle and inferior, which overlap from below upwards.
The Nasopharynx. At the junction of the roof and the posterior wall lies a
small mass of lymphoid tissue called the pharyngeal tonsil or adenoids. There
is a central mass of this tissue, and there are smaller accumulations of
lymphoid tissue laterally around the pharyngeal openings of the auditory
(Eustachian) tubes. These tubes connect the nasopharynx with the middle ear
cavities, and are lined by columnar ciliated epithelium in continuity with that
of the nasopharynx. Anteriorly the nasopharynx communicates with the nasal
cavities through the posterior nares.

The Oropharynx. This part is usually referred to as the 'pharynx', and is the
easiest part to examine when the patient opens his mouth. The free edge of the
soft palate forms the palatine arch which separates the oral cavity from the
pharynx. From its centre the uvula hangs downwards, and from the arch,
on either side, run two folds of mucous membrane, raised up by bands of
muscle fibres of the palatoglossus and palatopharyngeus muscles, to form the
palatoglossal and palatopharyngeal arches, or anterior and posterior pillars of
the fauces. The palatine tonsil lies between these folds.

The laryngopharynx- (hypopharynx) is that part of the pharynx which
extends from the base of the tongue to the upper end of the oesophagus. It is
lined by mucosa, and is enclosed within the three constrictor muscles of the
pharynx—superior, middle and inferior. The middle constrictor is attached to
the hyoid bone which gives stability to the hypopharynx. Lymphoid tissue is