NORMAL ANATOMY OF THE LARYNX. 



Ill 



veilhier.* The description given of it by 

 Morgagni is, that it consists of a granular sub- 

 stance of a livid whitish colour, from which 

 under the pressure of the epiglottic or neigh- 

 bouring muscles a fluid is poured out. Wris- 

 bergf described it as a cartilage under the name 

 of cuneiform. Cuvier and Wolff, as before 

 stated, have confounded it with the cartilage of 

 Santorini. Morgagni appears to have mistaken 

 for glandular the yellow elastic tissue pene- 

 trating its body. Lauth describes some mucous 

 follicles about its base and internal surface, 

 but he opposes the views of Morgagni on the 

 constitution of this body. This body is some- 

 times absent in the human subject, but scarcely 

 ever in the quadrumana. Its structure is de- 

 cidedly cartilaginous. 



The epiglottic gland. Syn. glandula epi- 

 glottidis, Fab. Cass. Morg. The epiglottic 

 gland is a name given to a mass of yellow 

 ligamentous adipose and cellular substance, 

 situated in the triangular space between 

 the anterior surface of the epiglottis and the 

 angle of the thyroid cartilage ; it is bounded 

 anteriorly by the thyro-hyoid membrane, above 

 by the thyro-epiglottic mucous membrane and 

 ligament; below, by the union of the epiglottis 

 with the thyroid cartilage, and on each side by 

 the mucous membrane passing from the thyroid 

 to the epiglottis. Berengarius speaks of it as a 

 fleshy gland : Steno and many others as com- 

 posed of granules, whose ducts perforate the 

 epiglottis and open on its posterior surface. 

 Fabricius, Casserius, and Morgagni J have de- 

 scribed and figured these supposed granules 

 and ducts. Bichat, Cloquet,|| Quain,H and 

 most modern anatomists adopt the same views. 

 Morgagni, upon the same supposition as he 

 had formed of the nature of the elastic tissue, 

 considers the composition of the epiglottis to 

 be chiefly glandular. Cloquet and Bichat 

 admit the difficulty of detecting any follicular 

 structure, nor could we discover any under the 

 microscope ; and from what has been already 

 stated on the structure of the epiglottis, we 

 conclude, as of the arytenoid, that the structure 

 which enjoys the name of epiglottic gland is 

 not glandular. 



Mucous membrane. The mucous membrane 

 of the larynx is continuous with that which 

 covers the mouth and pharynx. The posterior 

 surface of the larynx is bounded by the pharynx, 

 and is lined by mucous membrane both on its 



* Traite d'Anat. 



t Primae lineae phys. anat. a de Haller, ed.Wris- 

 berg. Getting. 1780-8. p. 157. 



$ Morg. advers. anat. om. tab. ii. p. 48. 



" Get espacc est occupe par un corps manifeste- 

 ment celluleux, et graisseux, dans sa plus grande 

 partie, mais qui est inferieurement recouvre de 

 petits grains glandulenx, tantot agglommeres, tantot 

 isoles, lesquels envoient sensiblement des prolonge- 

 mens dans les trous dont est percee 1'epiglotte : les 

 prolongemens paroissent s'ouvrir sur sa surface 

 laryngee, aux orifices qu'on y distingue. Quelque- 

 fois les petits corps glanduleux sont tellemcnt 

 masques par cette graisse jaunatre, qu'on ne peut 

 les distinguer." Traite d'Anat. dcscript. torn. ii. 

 p. 385. 



Anat. descript. p. 245. 

 Elem. of Anat. p. 858. 



\ 



anterior and posterior surfaces. If the state- 

 ment of Cruveilhier be correct, this singular 

 duplication is not to be found elsewhere in the 

 animal economy ; afterwards it is reflected over 

 the surface of the base of the tongue, and lines 

 the interior surface of the epiglottis ; in this 

 space it forms threefolds, called glosso-epiglottic, 

 often described as the middle, and two lateral, 

 which adhere closely to the surface of the epi- 

 glottis. The mucous membrane being reflected 

 over the free part of the epiglottis, to which it 

 rather closely adheres, then lines its posterior 

 surface and dips into the larynx. 



A duplication called the aryteno-epiglottic 

 fold passes from each side of the lateral mar- 

 gin of the epiglottis to the vertical apophysis of 

 the arytenoid cartilage. This membrane is 

 connected posteriorly with the mucous coat of 

 the pharynx, and lines the posterior surface of 

 the larynx ; it is reflected over the arytenoid 

 cartilages, and with the aryteno-epiglottic fold 

 forms the posterior and lateral superior margin 

 of the larynx ; covers the superior thyro-aryte- 

 noid ligaments, penetrates to the bottom of the 

 ventricles; from thence, after lining the inferior 

 thyro-arytenoid ligaments, it passes through the 

 chink of the glottis, covers the thyro and crico- 

 arytenoideus lateralis muscles, and the internal 

 surface of the cricoid cartilages, and becomes 

 the investing membrane of the trachea. 



The laryngeal membrane is perforated by 

 numerous mucous orifices of a peculiar pale 

 rose-colour, and is remarkable for its great sen- 

 sibility, more especially in the region above the 

 rima glottidis. 



2V;e rima glottidis. Syn. cavum sen sinus la- 

 ryngis The chink of the larynx is an aperture 

 directed horizontally, connecting the supra and 

 infra-Iaryngeal regions, and allowing the free 

 transmission of air in respiration. It is bound- 

 ed posteriorly by the arytenoid cartilages, ary- 

 tenoid muscle and mucous membrane ; laterally 

 by the arytenoid cartilages and the thyro-aryte- 

 noid ligaments, which, with the mucous mem- 

 brane reflected over them, present nearly rect- 

 angular-shaped valves, attached on three sides, 

 leaving one, bounding the glottis, free; ante- 

 riorly by the angle of the thyroid. Immedi- 

 ately above it are the ventricles, one on each 

 side. The intrinsic muscles of the larynx not 

 only contribute to its functions in the produc- 

 tion of voice, but determine its form. The form 

 of the chink of the glottis is variable; in the 

 state of repose, or that of ordinary respiration, 

 it is triangular, the aperture dilating during 

 inspiration and contracting during expiration. 

 When the arytenoids are separated to the great- 

 est extent by the crico-arytenoidei postici, it 

 assumes a lozenge form ; if the posterior bases 

 of the arytenoids are closed by the arytenoid 

 muscles it becomes an ellipse ; if the anterior 

 apophyses of the arytenoids meet by the action 

 of the crico-arytenoidei laterales, the chink may 

 be divided into two parts. The length of the 

 chink of the glottis is very variable, and bears a 

 relation to that of the thyro-arytenoid ligaments ; 

 like the latter, it increases with age in an arith- 

 metical proportion until the period of puberty ; 

 at that time its length in the. male sex under- 



