Lymph Vessels of the Major Salivary Glands (Sublingual, Submaxillary, and Parotid Gland)
a. Sublingual gland
The lymph vessels of the sublingual gland (Figure 15: r, r’) drain to the mandibular and medial retropharyngeal lymph nodes: those of the glandula sublingualis parvicanalaris drain to both groups of lymph nodes, while those from the glandula sublingualis grandicanalaris drain only to the medial retropharyngeal lymph node. Several lymph vessels arise from the glandula sublingualis parvicanalaris (Figure 15: r’) and proceed to merge into 2 to 3 smaller vessels. One to 2 of these vessels (Figure 15: 1) will join with the lymph vessels of the gingivae of the lingual side of the mandibular molars (pattern ii), running rostrally between the mucosa on the medial side of the mandible and the M. mylohyoideus for a varying distance, before turning ventrally, penetrating the M. mylohyoideus, and draining to the ventral mandibular lymph nodes.
Most of the lymph vessels draining to the ventral mandibular lymph nodes originate from the cranial part of the glandula sublingualis parvicanalaris. In addition, another 1 to 2 lymph vessels drain to the medial retropharyngeal lymph node. These lymph vessels mainly originate from the caudal part of the glandula sublingualis parvicanalaris, as shown in Figure 15, and run under the M. digastricus to drain to the medial retropharyngeal lymph node. The lymph vessels arising from the glandula sublingualis grandicanalaris (Figure 15: r) also merge to form several (though most commonly 2) trunks, which wrap around the nasodorsal margin of the M. digastricus to its medial side, joining the lymph vessels of the caudal part of the glandula sublingualis parvicanalaris, and running with them to the medial retropharyngeal lymph node (Figure 15: t)
b. Submaxillary (MAndibular) gland
The lymph vessels of the submaxillary gland (Figure 15: q) drained to the medial retropharyngeal lymph node (Figure 15: t) in 4 examined cases. Three to 5 lymph vessels emerge from the gland, mostly from its medial surface, though sometimes from its caudal border, and travel over both surfaces of the M. digastricus to drain to the medial retropharyngeal lymph node.
c. Parotid gland
Some of the lymph vessels of the parotid gland (Figure 15: p) drain to the parotid lymph node (Figure 15: s), and some drain to the medial retropharyngeal lymph node (Figure 15: t). The lymph vessels draining to the parotid lymph node originate mainly from the oral half of the gland and emerge from its ventral surface, while those draining to the medial retropharyngeal lymph node originate mainly from the caudal half of the gland, and, after they have left the gland on its ventral surface, travel as 4 to 5 vessels, some over the lateral and some over the medial side of the M. digastricus, to drain to the medial retropharyngeal lymph node. Lymph vessels draining from the parotid gland to the mandibular lymph nodes could not be found in 6 carefully examined cases. This finding is significant because, in the cow, the lymph vessels of the parotid gland were always found to drain to the mandibular lymph nodes.
