132 



APPLIED ANATOMY. 



has as its upper side the lower edge of the mandible from near its symphysis around 

 the lower edge of the body to the ramus and thence in a straight line across to the 

 mastoid process. Its anterior side is the anterior belly and its posterior side is the 

 posterior belly of the digastric muscle. The submaxillary gland can usually be felt 

 beneath the jaw. Beneath it runs the facial artery to pass over the body of the 

 mandible in front of the anterior edge of the masseter muscle. The gland lies on the 

 hyoglossus and mylohyoid muscles, which form the floor of this triangle. It is 

 encased in a sort of pocket formed by a splitting of the deep cervical fascia. The 

 posterior portion of this fascia runs from the styloid process to the hyoid bone and is 

 called the stylohyoid ligament. 



Lymphatic nodes lie on the submaxillary gland and in carcinomatous disease 

 they become enlarged and then can be readily palpated. In operating on these 



Facial arte 

 Lingual arte 



Occipital arte 



External jugular ve 



Edge of sternomastoi 



muse 



Internal jugular ve 



Descendens hypoglo: 

 ner 



External carotid arte 

 Superior thyroid arte 



Mylohyoid muscle 

 Hyoglossus muscle 

 Digastric muscle 

 Hypoglossal nerve 

 Tendon of digastric 



FIG. 164. Deeper structures of the submaxillary region, especially the vessels. 



lymphatic nodes for tuberculous disease, care should be taken to distinguish between 

 them and the submaxillary gland. The tendon of the digastric muscle does not 

 come clear down to the hyoid bone but the loop which binds the two together is 

 sometimes a centimetre or more in length. The lingual artery enters the sub- 

 maxillary triangle near the apex of the angle formed by the tendon of the digastric. 

 It crosses beneath the posterior belly of the digastric muscle and, particularly if the 

 digastric muscles contract, it may lie close to the tendon. Frequently the search 

 for it is made too high in the triangle and too far away from the hyoid bone. 

 When the submaxillary gland is lifted from its bed the hypoglossal nerve is seen 

 beneath lying on the hyoglossus muscle. The lingual artery lies beneath the hyo- 

 glossus muscle and the muscle is cut through in order to find it. The submaxillary 

 region is the seat of Ludwig' s angina, a septic inflammation involving the cellular 



