THE LYMPH GLANDS AND VESSELS OF THE HEAD AND NECK 699 



anterior part of the tongue, the jaws, the floor of the mouth, and the greater part 

 of the hard palate and nasal cavity. The efferent vessels pass to the anterior 

 cervical and pharyngeal glands. 



Most of the superficial lymph vessels of the face converge to twelve to fifteen trunks which 

 turn around the lower border of the jaw with and m front of the facial vessels. Those of the lips 

 form plexuses at the commissures. The nasal mucous membrane is richly supplied with lymph 

 vessels which accompany the veins; posteriorly they communicate with 'the subdural and sub- 

 araclmoid spaces and send efferents to the phar3mgeal and anterior cervical glands. 



2. The pharyngeal lymph glands (Figs. 562, 706) usually comprise two 

 groups. One lies on the upper part of the lateral surface of the pharynx, along the 

 course of the external carotid artery. These glands are related laterally to the 

 occipito-mandibularis and digastricus, and often to the mandibular gland also, 

 above to the guttural pouch; they may properly be termed the parapharyngeal 

 lymph glands (Lgg. parapharyngeales) . Other small glands are commonly found 

 on the guttural pouch along the course of the internal carotid artery ; thejr are best 

 designated as the suprapharyngeal lymph glands (Lgg. suprapharyngeales).! They 

 he below the artery and are covered by the aponeurosis of the brachiocephalicus 

 and the cervical end of the mandibular gland. In some cases a number of glands 

 occur in the angle of divergence of the external and internal carotid arteries. 



They receive afferent vessels from the cranium, the posterior part of the tongue, 

 the soft palate, pharynx, guttural pouch, larynx, posterior part of the nasal cavity, 

 and efferents from the mandibular glands. 



3. The anterior cervical lymph glands (Lgg. cervicales craniales) (Fig. 646) are 

 situated along the course of the common carotid artery, in the vicinity of the thjToid 

 gland, under cover of the cervical angle of the parotid gland. Some occur between 

 the thyroid and the mandibular salivary gland, others above and partly upon the 

 thyroid. They are related deeply to the posterior part of the larjaix, the trachea, 

 the thyroid gland, and the oesophagus; below to the external maxillary vein and 

 the lateral border of the omo-hyoideus.^ 



These glands are variable. Often there are none in front of the thyroid and the group may 

 extend back a considerable distance along the course of the carotid artery. 



Their afferents are deep lymph vessels from the head, the pharjmx, larynx, 

 guttural pouch, and thyroid gland, and efferents from the mandibular and pharj^n- 

 geal glands. Their efferent vessels go to the middle and posterior cervical glands. 



4. The middle cervical l5anph glands (Lgg. cervicales media) form an incon- 

 stant group situated a little in front of the middle of the neck on the trachea below 

 the carotid artery. The group is usually small, and in some cases is replaced by a 

 number of glands occurring at intervals along the course of the carotid artery. In 

 other subjects the group consists of several glands of considerable size. They are 

 intercalated in the course of the tracheal lymph ducts. 



5. The posterior cervical or prepectoral lymph glands (Lgg. cervicales caudales) 

 form a large group below the trachea at the entrance to the thorax (Fig. 590). 

 They occupy the interstices between the vessels and muscles and extend forward a 

 variable distance on the ventral aspect of the trachea. Posteriorly they are con- 

 tinuous with the anterior mediastinal glands. They are covered by the cutaneus 

 and stemo-cephalicus. Their afferent vessels come from the head, neck, thorax, 

 and thoracic hmb. They receive efferent ducts of the anterior and middle cervical, 

 prescapular, and axillary glands. Their efferents go to the thoracic duct on the 

 left, to the right lymphatic duct on the right, or open directly into the vena cava. 



6. The prescapular or superficial cervical lymph glands (Lgg. cervicales 



1 Much confusion exists in the terminology used in regard to these glands and the next group. 

 The terms here recommended appear to the author to be the best, all thmgs considered. The 

 pharyngeal and anterior cervical glands are all subparotid in the horse. 



2 Abscess here can be reached readily by an incision between the vein and the omo-hyoideus. 



