146 



APPLIED ANATOMY. 



muscle; the second, the part beneath the hyoglossus muscle; and the third, the part 

 beyond this muscle to the tip of the tongue. 



The artery is usually ligated beneath the hyoglossus muscle in the second part of 

 its course, although it is sometimes desirable to ligate it in the first part of its course. 



The \first part inclines upward and forward, above the greater horn of the hyoid 

 bone, to the hyoglossus muscle, beneath which it passes in a direction somewhat 

 parallel to the upper edge of the hyoid bone. It lies on the middle constrictor of 

 the pharynx and superior larnygeal nerve and is covered by the skin, platysma, and 

 fascia. It lies immediately below the stylohyoid and digastric muscles and is crossed 

 by the hypoglossal nerve and some veins. This portion frequently gives off a hyoid 

 branch which runs above the hyoid bone. It is often missing, in which case the 

 parts are supplied by the hyoid branch of the superior thyroid. From either the end 

 of the first part or the beginning of the second part, the dorsalis linguae branch arises. 



The second part of the lingual lies on the superior constrictor and geniohyoglos- 

 sus muscles and is covered by the hyoglossus. It runs in a direction somewhat 

 parallel to the upper edge of the hyoid bone and from 0.5 to I cm. above it. In this 



/ 



Mylohyoid muscle 



Submaxillary gland 



Anterior belly of 

 digastric muscle 



Lingual artery 



Tendon of 

 digastric muscle 



Hypoglossal nerve 

 sLingual vein 



edge of the hyoglossus muscle 

 FIG. 174. Ligation of the lingual artery 



Cut 



part of its course it is usually accompanied by one or two veins and the hypoglossal 

 nerve is superficial to it, the hyoglossus muscle separating them. This is the part 

 of the artery chosen for ligation. An incision is made, convex downward, running 

 from below and to one side of the symphysis nearly down to the hyoid bone and 

 then sloping upward and back, stopping short of the line of the facial artery, which 

 can be determined by the groove on the mandible just in front of the masseter muscle. 

 The skin, superficial fascia, and platysma having been raised, the submaxillary gland 

 is seen covered with a comparatively thin deep fascia. Some veins coming from the 

 submental region may then be encountered. They may be ligated and divided. 

 The submaxillary gland is next to be lifted from its bed and turned upward against 

 the mandible, carrying with it the facial artery, which is adherent to its under sur- 

 face. The tendon of the digastric will now be seen with the anterior and posterior 

 bellies of the muscle forming an angle with its point toward the hyoid bone. These 

 with the hypoglossal nerve form what has been called the triangle of Lesser. It is 

 in this space that the artery is ligated. The floor of the space posteriorly is formed 

 by the hyoglossus muscle, while anteriorly is seen the edge of the mylohyoid muscle. 

 Through the thin fascia overlying the hyoglossus muscle can be seen the hypoglossal 



