912 



THE ORGANS OF VOICE 



On plionation the cords bt'conic parallel and closely approximated, and the 

 vocal processes ap})roaching each other cause the angle to be turned inwards. 



The infrarimal portion of the larynx rapidly widens out into a nearly circular 

 cavitv at the lower border of the cricoid cartilage, from which point it is continuous 

 witli the lunuui of the trachea. 



Nerves. — The nerves of the larynx are derived from the superior and inferior 

 (recurrent ) laryngeal l)ranc]ies of tlie vagus. 



The superior laryngeal. — The sensory nerve of the larynx gives ofT near its 

 origin behind tlie carotid sheath a long and slender filament, Avhich is principally 

 motor. This (external) branch is distributed to the crico-thyroid muscle, a few 

 minute filaments reaching the mucous membrane of the larynx. 



Its larger and main branch (internal) is sensory, and passes through the 



Fig. 535. — Nerves of the Laryxx. (Posterior view.) 



GREATER CORNU OF 



HYOID BONE 

 CARTILAGO TRITICEA 



SUPERIOR CORNU OF 

 THYROID CARTILAGE 



BRANCH TO LA TEBAL 

 VRICO - ARYTENOID 

 AND THTRO-ARTTE- 

 SOID .VVSCLES 

 H RANCH JOINING THE 

 srPERIOR LARYN- 

 GEAL NERVE 

 Crieo-arytenoideus 

 posticus muscle 

 INFERIOR CORNU OF 

 THYROID CARTILAGE 



FORAMEN C/ECUM 



BASE OF TONGUE 



EXTERXAL LARYN- 

 GEAL NERVE 



INTERNAL LARYN- 

 GEAL NERVE 



, Cut edge of thyro- 

 hyoid membrane 



Arytenoideus muscle 



RECURRENT 

 LARYNGEAL 

 NER VE 



aperture in the thyro-hyoid membrane above the superior laryngeal artery. It 

 divides l)eneath the mucous membi'ane which lines the sinus pyriformis, distributing 

 branches upwards to supply both surfaces of the epiglottis and the base of the 

 tongue immediately in front; inwards to the aryteno-epiglottidean fold and its 

 neighbourhood; whilst others pass downwards to the mucous membrane of the 

 deeper portions of the larynx as far as the true vocal cords. 



The inferior (recurrent) laryngeal, the motor nerve of the larynx, ascends in 

 the groove between tbe traeliea and (esophagus, l)oth of which structures it supplies. 

 It reaches the larynx below the edge of the inferior constrictor, and immediately 

 behind the crico-thyroid_ joint. At this spot it divides into two l»ranches: an 

 anterior to su])]»ly the thyro-arytenoideus, crieo-arytenoideus lateralis, Avith the 

 niuseles of the epiglottis; and a posterior branch to the crieo-arytenoideus posti- 

 cus and arytenoideus. 



