130 



APPLIED ANATOMY. 



the upper and outer portion of the manubrium, the sternoclavicular ligament, and the 

 inner end of the clavicle. The origin of the sternothyroid is wider than that of the 

 sternohyoid and is lower down. It arises from the first piece of the sternum near the 

 median line, below the sternohyoid, and from the cartilage of the first rib. The first 

 ring of the trachea is not covered by any important structure. The second, third, 

 and fourth rings are covered by the isthmus of the thyroid gland; from here down 

 the inferior thyroid veins may lie on the trachea for at least part of their course. The 

 anterior jugular vein may exist either as a single vein in the median line or to one 

 side of it, or one may pass downward on each side of the median line with a communi- 

 cating branch from one to the other crossing the median line in the suprasternal notch. 

 The cricothyroid artery, a small branch of the superior thyroid, may cross the crico- 

 thyroid membrane, but it is usually too small to cause any troublesome bleeding. 



Structures to be Felt in the Median Line. On passing the finger down- 

 ward from the symphysis it sinks into a hollow, on crossing which the hyoid bone is 



Anterior belly of digastric 



Sternohyoid 



Anterior belly of 

 omohyoid 



Submaxillary triangle 



Superior carotid triangle 

 Occipital triangle 



Inferior carotid triangle 

 Trapezius 



Posterior belly of omohyoid 

 Subclavian triangle 



FIG. 162. Showing anterior and posterior cervical and subsidiary triangles. 



felt. On pressing the finger into this hollow it rests between the digastric muscles 

 on each side and the mylohyoid muscles beneath. Still deeper than the mylohyoid 

 are the geniohyoid and geniohyoglossus muscles attached to the genial tubercles on 

 the inner side of the mandible. If the lymphatic nodes at this point are enlarged 

 they may be felt. (Fig. 161.) 



The hyoid bone can usually be readily felt in the median line. If it is not easily 

 discovered in the median line it can be felt by a finger and thumb placed on each 

 side of the neck above the thyroid cartilage. 



Passing over the hyoid bone the finger then sinks into the space between it and 

 the top of the thyroid cartilage. This space is bridged by the thyrohyoid mem- 

 brane. Next comes the thyroid cartilage or "Adam's apple." It can readily be 

 seen in adult males and thin people, but in the fat necks of women and children, 

 though it can still be felt, it often cannot be seen. The finger then sinks into the 

 space between the thyroid cartilage above and the cricoid below. They are con- 

 nected by the cricothyroid membrane, over which runs a small branch (cricothyroid) 

 of the superior thyroid artery. 



