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

SECTION

ARYNX, I
I OESOPI

A. G. D. Maran

THE LARYNX, BRONCHI
AND OESOPHAGUS

CHAPTER 30

ANATOMY AND PHYSIOLOGY OF
THE LARYNX

The larynx is an integral part of the respiratory tract and is the organ of voice
production. Only the essential parts of the anatomy will be dealt with in this
chapter as specialized points will be mentioned in chapters relating to the
appropriate diseases.

SKELETON

The main part of the laryngeal skeleton is formed by the thyroid cartilage
which articulates with the cricoid inferiorly. The hyoid bone lies superiorly
(Fig. 58). The epiglottis is attached to the thyroid prominence (Adam's apple)
at the level of the vocal cords and forms the anterior wall of the laryngeal'
compartment. Anterior to the epiglottis (between the epiglottis and the
thyroid cartilage, thyrohyoid membrane and hyoid) is the pre-epiglottic space
(Fig. 59,2), an area into which cancer spreads readily. From the sides of the
epiglottis two folds of mucosa pass posteriorly to be attached to the arytenoids;
these are the ary-epiglottic folds and they form the lateral wall of the upper
laryngeal compartment (Fig. 60). They have a very rich lymphatic supply and
so tumours of this area have a three out of four chance of producing a
metastatic neck node. Laterally, the space between the ary-epiglottic fold and
the thyroid cartilage is the pyriform fossa which is part of the pharynx. Food
passes over the back of the tongue and down the lateral food channels formed
by the pyriform fossae before entering the oesophagus. Inferiorly, the ary-
epiglottic fold turns laterally to form the laryngeal ventricle immediately
superior to the vocal cords (folds). The thick area where it turns laterally is
the false vocal cord (ventricular folds) and shares the same rich lymphatic
drainage*

The laryngeal ventricle (Fig. 59, 4) is the site of the primitive air sac and
lies between the vocal and ventricular folds. It is the potential origin of a
laryngocele.

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