124 



LARYNX. 



and is inserted into the perineal centre. Sometimes there is an 

 additional portion in front, called trafisversus perinei alter. 



Sphincter ani.^ — A thick muscular ring surrounding the anus. 

 lis superficial fibres are elliptical. It is connected with the coccyx 

 and perineal centre. 



Fig. 105. 



Coccygeiis}^ — Origin^ from the spine of the ischium. Insertion^ 

 into the side of the coccyx and last bone of the sacrum. 



Sacro-coccygeus. — A few fibres passing from the sacrum to the 

 coccyx in front. 



Levator ani^ — Is a plane of muscular fibres. Origin, from the 

 interior of the body of the pubes, the superior edge of the thyroid 

 foramen, and the spine of the ischium. Insertion, by converging 

 and descending fibres into the lateral semi-circumference of the 

 rectum ; also into the coccyx and perineal centre. 



ORGANS OF RESPIRATION AND CIRCULATION. 



LARYNX. 



The larynx is a canal formed of cartilages which move in such 

 a manner as to regulate the voice. 



It is situated in the upper and anterior part of the neck, in the 

 median line, below the hyoid bone. 



It forms tlie commencement of the windpipe ; is cylindrical below, 

 but prismatic above ; it is larger in males than in females. 



The cartilages of the larynx are five in number; thyroid, cricoid, 

 two arytenoid, and epiglottis. 



The thyroid is the largest ; it occupies the upper and anterior 



