156 APPLIED ANATOMY. 



Retropharyngeal Abscess. Pus which tends to point into the pharynx may come 

 from disease of the vertebrae, in which case it is posterior to the prevertebral fascia; 

 or it may originate from the lymphatic nodes in the retropharyngeal space. 



When coming from caries of the vertebrae, it may point either in the pharynx 

 or, pushing its way outward, pass behind the great vessels and show itself behind 

 the outer edge of the sternomastoid muscle. I have seen it point in both these 

 places in the same case. When originating in the retropharyngeal space it lies in 

 front of the prevertebral fascia and behind the buccopharyngeal fascia. It either 

 points forward into the pharynx or, going down, follows the posterior surface of the 

 oesophagus into the posterior mediastinum. It may also perforate the oesophagus 

 and enter its lumen. 



Pus in the Posterior Cervical Triangle. If above the prevertebral layer this 

 bulges directly forward and tends to open through the skin. Its progress downward 

 is obstructed by the attachment of the superficial layer to the top of the clavicle as 

 it blends with the prevertebral layer. If pus is beneath the prevertebral layer it may 

 then follow the brachial plexus and subclavian artery down beneath the clavicle and 

 appear in the axilla. The attachments of the costocoracoid membrane tend to direct 

 the pus laterally under the pectoralis minor muscle into the axilla rather than to allow 

 it to come forward on the anterior portion of the chest. 



LYMPHATICS OF THE NECK. 



The lymphatics of the neck are both superficial and deep. The superficial 

 nodes communicate freely with and end in the deep ones. For the sake of conven- 

 ience we may divide them into a transverse set, embracing the submental, siibmaxillary , 

 superficial upper cervical (behind the angle of the jaw), posterior aurictdar, and 

 occipital nodes ; and two longitudinal sets, one along the great vessels and another, a 

 posterior set, in the posterior cervical triangle. 



The Transverse Lymphatics. The submental nodes, also called the supra- 

 hyoid, lie beneath the chin and drain the region of the lower lip and chin and anterior 

 part of the floor of the mouth. These will be enlarged in children with ulcerative skin 

 affections of these regions. They may also be involved in carcinoma of the lower lip, 

 especially if near the median line. That the submental nodes drain the tissues of the 

 anterior portion of the mouth and probably the tongue itself is shown by Henry T. 

 Butlin ("Surgery of Malignant Disease," p. 153), who states that the submental 

 nodes are frequently affected in carcinoma of the tongue when its tip is involved. 



The subrnaxillary nodes are beneath the body of the mandible in the sub- 

 maxillary triangle. They drain the lips, nose, floor of the mouth, gums, anterior 

 portion of the tongue and side of the face. These are the nodes most frequently 

 affected in carcinomatous affections of the lips and anterior portion of the tongue. 

 Henry T. Butlin ("Surgery of Malignant Disease," p. 153) calls attention to the 

 fact that in malignant disease of one side of the anterior portion of the tongue the 

 lymphatics of the opposite side may also be involved, thus showing that the lym- 

 phatics of the two sides of the tongue freely anastomose. This is contrary to what 

 exists as regards the arteries, which anastomose hardly at all across the median line. 

 He also states that one or more of the lymphatic nodes is frequently imbedded in the 

 substance of the subrnaxillary gland. Therefore the subrnaxillary gland is excised at 

 the same time as the affected lymphatic nodes. 



The superficial ^lpper cervical (subparotid} nodes are just below the parotid 

 lymphatics and behind the angle of the jaw. They drain the region embraced by 

 the masseter muscle as far back as the ear. They may be enlarged in affections of 

 the skin and scalp above. Therefore in children with enlargement of these nodes 

 the source of infection should be sought in those regions. 



The posterior aiiricular nodes are behind the ear on the mastoid process and 

 insertion of the sternomastoid muscle. In practice they are encountered as small 

 (i cm.), round swellings behind the ear, which are usually quite tender to the touch. 

 This is probably due to their being placed on a hard, bony base. When enlarged 

 they are often the subject of operations. 



