602 THE VEINS 



thin layer of fascia and panniculus, and are therefore palpable. Anteriorly they 

 are firmly attached to the mylo-hyoidei, but otherwise they are rather movable 

 in the normal state. Each group is related externally to the external maxillar>' 

 artery and the anterior bell_v of the digastricus, below to the external maxillary 

 vein, and above to the lingual and sublingual veins. 



They receive afferent vessels from the lips, nostrils, nasal region, cheeks, the 

 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. 



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

 around the lower border of the jaw with the facial vessels. Those of the lips form plexuses at 

 the commissures. The nasal mucous memlsrane is richly supplied witli lympli vessels which 

 accompany the veins; posteriorly they communicate with the subdural and subarachnoid spaces 

 and send efferents to the pharynjical and anterior cervical glands. 



2. The pharyngeal lymph glands (Figs. 436, 437, 569) may consist of two 

 groups. One lies on the lateral surface of the pharynx along the course of the ex- 

 ternal carotid artery. These glands are related externally to the stylo-maxillaris 

 and digastricus and often to the submaxillary gland also, above to the guttural 

 pouch. Other glands (Lg. retropharyngeales) are commonly found on the guttural 

 pouch along the course of the internal carotid artery. They lie beloAV the artery 

 and are covered by the aponeurosis of the mastoido-humeralis and the cervical 

 end of the submaxillary gland. 



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 submaxillary glands. 



3. The anterior cervical lymph glands (Lg. cervicales craniales) are situated 

 chiefly along the course of the common carotid artery in the vicinity of the thyroid 

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

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

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

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

 vein and the outer 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 pharynx, larynx, 

 guttural pouch, and thyroid gland, and efferents from the submaxillary and pharyn- 

 geal glands. Th(Mr (^ffc^rent vessels go to the middle and posterior cervical glands. 



4. The middle cervical lymph glands (Lg. cervicales media;) form an inconstant 

 grou]) 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 absent, being 

 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 trach(Md lyni])h ducts. 



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

 form a large group below the trachea at the entrance to the thorax (Fig. 466). 

 They occupy the intei-stic(^s between the vessels and musck^s and extend forward a 

 variable distance on the ventral aspect of the trachea. Thej^ are covered by the 

 panniculus and sterno-cephalicus. Their afferent vessels come from the head, 

 neck, thorax, and thoracic limb. 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 lym])lKitic duct on the right, or o]ien directly into the 

 vena cava. 



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

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



