Only the lymph vessels of the external ear were examined. These were found to drain to the parotid, retropharyngeal, and superficial cervical lymph nodes.
A. Lymph Vessels of the Ear Muscles
The lymph vessels of the ear muscles drain either to the parotid lymph node or to the retropharyngeal lymph nodes. The lymph vessels of the M. scutularis and the pinna adductors merge into 2 to 3 larger vessels and drain to the parotid lymph node. Additionally, 2 lymph vessels were always observed to emerge from the pinna abductors and to drain to the medial retropharyngeal lymph node, and, if a lateral retropharyngeal lymph node was present, also to it. The lymph vessels of the M. depressor auris usually merge to form 2 trunks, which then drain to the lateral and medial retropharyngeal lymph nodes. For the lymph vessels of the M. stylohyoideus, see lymph vessels of the individual muscles of the tongue and hyoid bone.
B. Lymph Vessels of the Pinna
Most of the lymph vessels of the pinna (Figures 13, 14) drain to the superficial cervical lymph nodes (Figure 13: 3), while a smaller number drain to the lateral retropharyngeal (Figure 14: s’’) and medial retropharyngeal lymph nodes (Figure 13: 12), as well as to the parotid lymph node (Figure 13: 1). The lymph vessels of the conchal cartilage and those of the skin on the inner and outer sides of the conchal cartilage join with each other so that they can be described collectively. More specifically, the lymph vessels of the skin on the inner side of the conchal cartilage form coarse subcutaneous networks; the lymph vessels emerging from these networks pass through the conchal cartilage, merging with the lymph vessels of the conchal cartilage, and then joining the lymph vessels of the skin on the outer side of the pinna. The latter lymph vessels form coarse subcutaneous networks, which are distributed over the entire dorsum of the pinna, then merge with those of the skin of the parietal region, from which a larger number of lymph vessels emerge. Most of these lymph vessels join with the lymph vessels of the skin of the back of the neck (nuchal region) (see lymph vessels of the skin of the neck) and drain with them to the superficial cervical lymph nodes (Figure 13: 3). Three to 5 lymph vessels from the part of the pinna adjacent to the lateral rim of the pinna run down either the caudal side of the cartilaginous auditory canal or just caudal to it to drain to the lateral and medial retropharyngeal lymph nodes (Figures 13: 12; 14: s’’, u). Finally, 2 to 3 lymph vessels originating from the part of the pinna adjacent to its medial edge descend directly in front of the pinna to drain to the parotid lymph node (Figure 13: 1), crossing both the inner and outer surfaces of the pinna adductors.