1586 A MANUAL OF ANATOMY 



of them in the text. To expose the middle meatus completely the middle 

 concha is to be removed with the scissors. The dissector will then see the 

 deep curved groove, called the hiatus semilunaris, at the upper and anterior 

 part of which will be found the infundibulum. The bulla ethmoidalis will 

 be evident, and the atrium and vestibule are to receive attention. By 

 clipping away the anterior part of the inferior concha a view will be obtained 

 of the lower orifice of the nasal duct, with its imperfect mucous fold, known 

 as the valve of Hasner. The distance of the orifice of the nasal duct from the 

 anterior nasal aperture should be carefully inspected. A probe should be 

 passed through the nasal duct, and the direction taken by the probe noted. 

 A Eustachian catheter should also be passed straight backwards through 

 the inferior meatus, and the mode of introducing it into the lower orifice 

 of the Eustachian tube should be inspected and practised. 



The dissection of the otic ganglion and of Meckel's ganglion may now be 

 completely overtaken, it being left to the discretion of the dissector to remove 

 whatever portions of bone may be necessary, after a perusal of the descrip- 

 tions which are given of these ganglia and their branches in the text. 



Larynx. — The lar5nix, with the tongue, is to be separated from the superior 

 maxilla and the lateral parts of the inferior maxilla. The superior aperture 

 of the larynx and the epiglottis are to be carefully studied, and, on looking 

 down through the superior aperture, the rima glottidis is to be inspected, 

 with a true vocal cord on either side of it. A little above each true vocal cord 

 the less distinct false vocal cord may be seen. In connection with the superior 

 aperture, the comicula laryngis, or cartilages of Santorini, are to be noted, 

 as well as the cuneiform cartilages, or cartilages of Wrisberg. Between the 

 arytenoid cartilage and the back part of the ala of the thyroid cartilage the 

 recess known as the sinus pjrriformis is to be looked for, and its downward 

 direction is to receive attention, which accounts for a foreign body being liable 

 to become lodged within it. The position of the great cornu of the hyoid bone 

 on either side should also receive attention, inasmuch as from an external ex- 

 amination of the upper part of the neck it might possibly be taken for, say, a fish- 

 bone. In the dissection of the larynx, the dissectors, who must act in concert, 

 should keep in view (i) the superior laryngeal nerve, its external, as well as 

 its internal, branch; (2) the inferior or recurrent laryngeal nerve; and (3) the 

 superior and inferior laryngeal arteries ; but the latter may not be sufficiently 

 injected for dissection. The internal laryngeal nerve will be found piercing 

 the [thyro-hyoid membrane, and the external laryngeal nerve is traceable to 

 the crico-thyroid muscle and the lower part of the inferior constrictor muscle 

 of the pharynx. The recurrent laryngeal nerve will be found close behind 

 the crico-thyroid joint. 



The larynx being placed with its posterior surface upwards, the two 

 posterior crico-arytenoid muscles will admit of easy dissection by removal 

 of the mucous membrane. They will be found upon the extensive posterior 

 surface of the cricoid cartilage. The median vertical ridge on the posterior 

 surface of the cricoid cartilage will be found to give origin superiorly to 

 the longitudinal muscular fibres of the oesophagus. In dissecting the 

 arytenoid muscle, which extends between the posterior surfaces of the ary- 

 tenoid cartilages, the dissector should first show the two decussating ary- 

 taeno-epiglottidei muscles. To follow out each of these muscles, the outer 

 layer of the aryteno-epiglottidean fold of mucous membrane requires to be 

 carefully removed. The cornicula laryngis may now be shown. They will 

 be found to cap the arytenoid cartilages, and not far from them the cuneiform 

 cartilages may be exposed in the back part of the aryteno-epiglottidean folds 

 of mucous membrane, already familiar to the dissector in connection with 

 the superior aperture of the larynx. 



At this stage it may be said that the dissectors cannot possibly expect 

 to obtain anything like a satisfactory knowledge of such an important struc- 

 ture as the larynx from the dissection of one specimen. The larynx should 

 be dissected several times. However, assuming that the time and oppor- 

 tunities of the dissectors are limited, the cricoid and thyroid cartilages may 

 now be studied, followed by the crico-thyroid and crico-arytenoid joints. 

 The thjrro-hyoid membrane is to be dissected, and the epiglottis is to be 



