The Neck. 475 



mediately below the hyoid bone, it passes between the epi- 

 glottis and the base of the tongue, but, if it be directed 

 immediately backwards, the body of the epiglottis itself 

 will be severed. The upper end of the angle of junction 

 of the two halves, or alse, of the thyroid cartilage, is called 

 the pomun Adami. About the centre of this angle of 

 junction is the attachment of the true vocal cords, while, 

 one-quarter of an inch above this point, is the attachment 

 of the epiglottis. Below the thyroid is the cricoid car- 

 tilage, and between them there is stretched a membrane 

 the crico-thyroid having the crico-thyroid artery run- 

 ning along its anterior surface, near the lower border of 

 the thyroid cartilage. Below the cricoid cartilage is the 

 trachea, with the lateral lobes of the thyroid gland on 

 either side and the isthmus overlying it. The distance 

 from the cricoid cartilage to the tipper border of the ster- 

 num, in a child five years of age, is about one and a half 

 inches, but, when the neck is extended, about three- 

 quarters of an inch is gained ; whereas, in the adult, 

 the distance from the cricoid to the sternum is about two 

 and a half inches, with a gain of three-quarters of an inch, 

 when the head is extended. There are only seven or 

 eight tracheal cartilages between the cricoid and the ster- 

 num, and of these the second and third, and sometimes the 

 fourth, are covered by the isthmus of the thyroid gland. 

 The cricoid cartilage corresponds to: (1) The junction of 

 the two bellies of the omo-hyoid ; (2) the point where this 

 muscle crosses the common carotid artery; (3) the centre 

 for the incision in ligating the common carotid artery; 

 (4) the junction of the larynx and trachea, and of the 

 pharynx and oesophagus; (5) the narrowest part of the 

 pharynx, and, lastly, (6) the lower border of the fifth cer- 

 vical vertebra. 



