THE HEAD AND NECK 



1283 



Interior of the Larynx. — The superior aperture of the larynx is 



situated behind and below the epiglottis. It is triangular, being 

 wide in front and narrow behind, and its plane is sloped obliquely 

 downwards and backwards. Above and in front it is bounded by 

 the epiglottis, and behind by the fold of mucous membrane which 

 stretches bet^veen the arytenoid cartilages. On either side are the 

 prominent ar\'teno-epiglottidean folds, which extend from the tips 

 of the arytenoid cartilages to the sides of the epiglottis and contain 

 muscular fibres. Each of these folds, close to the arytenoid cartilage, 

 contains the comiculum laryngis or cartilage of Santorini, which 

 gives rise to a slight elevation, and a little in front of this it presents 

 another slight elevation produced by the cuneiform cartilage or 

 cartilage of Wrisberg. Between the arytenoid cartilage and the 

 back part of the aryteno-epiglottidean fold internally and the back 

 part of the ala of the thyroid cartilage extemaJly there is a 

 depression, opening upwards, called the sinus pyriformis. In this 

 depression a foreign body may become lodged. 



The interior of the larynx commences at the superior aperture 

 and terminates on a level with the lower border of the cricoid 

 cartilage. It is divided into three compartments by means of two 



antero-posterior folds of mucous membrane, v.hich project into it 



from each lateral wall. The 



upper pair of folds are called Epigiouis 



the false vocal cords, and the 



lower pair the true vocal cords. 



The upper compartment is 



known as the vestibule, and it 



extends from the superior aper- 

 ture down to the level of the 



false vocal cords. It is wider 



above than below, and its 



anterior depth exceeds the pos- 

 terior. The middle or ventricular 



compartment is situated between 



the false vocal cords above and 



the true vocal cords below. On 



either side it presents a recess, 



called the ventricle of the larynx 



or laryngeal sinus. This is 



bounded above by a false vocal 



cord, and below by a true vocal 



cord. Its outer wall is covered 



externally by fibres of the 



thyro-arytenoid muscle. At the anterior part of the ventricle 



there is a small valvular aperture, which leads to a diverticulum 



of the ventricle, called the laryngeal saccule or pouch. This 



extends upwards between the false vocal cord and the ala of 



the thyroid cartilage, reaching as high as the upper border of 



the latter. On its inner aspect there are some muscular fibres. 



^{^Vestibule 



Ala of Thyroid Cartilage 

 — Middle Compartment 



Cricoid Cartilage 

 Lower Compartment 



Tnu±ea 



Fig. 531. — Vertical Transverse 

 Section of the Larynx, showing 

 THE Posterior Surface of the 

 Anterior Half of the Organ 

 (Marshall). 



