THE NECK. 



129 



of growths, operative incisions, etc. They comprise the space between the trapezius 

 muscle posteriorly, the median line anteriorly, the clavicle below, and the lower jaw- 

 above. 



Viewed from in front, the median portion of the neck may be divided into three 

 regions, the submental, laryngeal, and tracheal. 



The submental region extends from the chin to the lower border of the body 

 of the hyoid bone ; it is limited laterally by the anterior belly of the digastric mus- 

 cle on each side. Ranula and other sublingual tumors cause a bulging in this region 

 and it is frequently occupied by an enlarged lymphatic node, which at times sup- 

 purates and forms an abscess. The floor of the space is formed by the mylokyoid 

 muscle and there are no dangerous structures, so that no hesitancy need be had in 

 incising abscesses in this locality nor in removing diseased lymph-nodes. In carci- 

 noma involving the lower lip near the median line these nodes may be affected and 



Anterior belly of digastric 

 Submaxillary gland 



Hyoid bone 

 Thyrohyoid membrane 



Thyroid cartilage 

 Cricothyroid membrane 

 Cricoid cartilage 

 Sternomastoid muscle 



Thyroid gland 



FIG. 161. Anterior surface of the neck. 



their involvement in such cases should always be looked for. The submaxillary 

 lymphatic nodes farther outward may also be implicated. The tip of the epiglottis 

 projects above the hyoid bone in this region. 



The laryngeal region extends from the under surface of the hyoid bone to the 

 lower edge of the cricoid cartilage. Laterally it is limited to the space occupied by 

 the larynx. The cricoid cartilage is included in this region as a' part of the larynx. 

 The vocal cords are just beneath the most prominent part of the thyroid cartilage. 



The tracheal region extends from the lower edge of the cricoid cartilage to 

 the top of the sternum. Just above the sternum, between the sternal origins of the 

 Sternomastoid muscles, is the suprasternal notch or, as it is called by the Germans, 

 the Jugulum. Laterally the region is limited by the sides of the trachea. 



There are seven or eight rings of the trachea between the cricoid cartilage and 

 the top of the sternum. It is covered partly by the sternohyoid and sternothyroid 

 muscles. The former in the lower half of their course pass outward, leaving a space 

 in which the sternothyroid muscles are seen. The sternohyoid muscle arises from 



