252 THE VASCULAR SYSTEMS 



it is anterior and internal to the internal carotid, and at its 

 termination is embedded in the parotid gland. 



Relations. In front, integument and fasciae, sternomastoid, 

 digastric, and stylohyoid muscles, part of the parotid gland, 

 facial and hypoglossal nerves, lingual, facial, and temporomaxil- 

 lary veins; behind, styloid process with its remaining muscles, 

 part of the parotid gland, and the glossopharyngeal nerve; 

 internally, pharynx, hyoid bone, part of the parotid, separat- 

 ing it from the lower jaw and stylomaxillary ligament, stylo- 

 glossus, and stylopharyngeus muscles, and the superior laryngeal 

 nerve. 



The branches of the external carotid, besides those given oil' 

 directly to the muscles in its course and to the parotid gland, 

 are the following: Anterior branches, superior thyroid, lingual, 

 facial; posterior branches, occipital, posterior auricular; internal 

 branch, ascending pharyngeal; terminal branches, superficial 

 temporal and internal maxillary. 



I. The superior thyroid runs beneath the omohyoid and sterno- 

 hyoid and thyroid muscles to the gland, uniting with its fellow 

 and with the inferior thyroid. It supplies the gland, the muscles 

 in its course, and the following named branches: 



(a) Hyoid, to lower border of the bone, joins its fellow. 



(b) Superficial descending or sternomastoid crosses the common 

 carotid to the sternomastoid muscle. 



(c) Superior laryngeal, beneath the thyrohyoid, pierces mem- 

 brane to interior of the larynx with the superior laryngeal nerve. 



(d) The cricothyroid runs across that membrane and joins its 

 fellow. 



II. The lingual ascends to the great cornu of the hyoid bone, 

 runs forward parallel with it, ascends to the tongue, and runs 

 along its under surface to the tip. It is at first superficial, lying 

 on the middle constrictor; later covered by the digastric and 

 stylohyoid, resting on the same muscle. It then ascends be- 

 tween the hyoglossus and genioglossus; finally, as the raninr 

 artery, it runs on the lingualis to the tip of the tongue, along 

 with the gustatory nerve, covered only by mucous membrane. 

 The first part is crossed by the hypoglossal nerve. , The second 

 part is in the triangle formed by the diverging bellies of the 

 digastric below and the hypoglossal nerve above. The artery 

 lies above the central tendon of the digastric, below the nerve, 

 and beneath the hyoglossus. Branches: 



