Lymph Vessels of the Tongue

A small number of the tongue’s lymph vessels drain to the mandibular lymph nodes, but most of the lymph vessels drain to the medial retropharyngeal lymph node. The lymph vessels of the tip of the tongue drain to both groups of lymph nodes, while those of the body and base of the tongue drain only to the medial retropharyngeal lymph node.

a. LYMPH Vessels of the tip of the tongue

The lymph vessels of the tip of the tongue (Figure 14: 6, 6’, 6’’) are divided into two groups: superficial lymph vessels and deep lymph vessels. Some drain to the mandibular lymph nodes (Figure 14: t, t’), and some drain to the medial retropharyngeal lymph node (Figure 14: u). The superficial lymph vessels emerge from under the mucosa on the ventral aspect of the tip of the tongue. Some (Figure 14: 6) run on the outer side of the M. mylohyoideus into the mandibular lymph nodes, while others (Figure 14: 6’, 6’’) curve around either the rostral or the ventral border of the M. genioglossus to its medial side and join the deep lymph vessels. The deep lymph vessels emerge between the lingual muscles and run deeply on the lateral and medial sides of the M. genioglossus, and then some of the lymph vessels emerge on the ventral border of the M. styloglossus, some through the M. hyoglossus, and turn over the pharyngeal muscles to drain into the medial retropharyngeal lymph node. At the tip of the tongue, the lymph vessels are always found to cross the median plane, so that when the left half of the tongue is punctured and injected, the lymph vessels also go to the lymph node on the right side, and vice versa.

b. LYMPH Vessels of the body of the tongue

The lymph vessels of the body of the tongue (Figure 14: 5, 7, 7’, 8) drain to the medial retropharyngeal lymph node. A small number of vessels run superficially (Figure 14: 7), under the mucous membrane of the lateral surface of the tongue, but most run deeply (Figure 14: 7’, 8), under the M. styloglossus, though some may run through the M. hyoglossus instead (Figure 14: 5), and drain together with the lymph vessels of the tip of the tongue over the pharyngeal muscles into the medial retropharyngeal lymph node.

c. LYMPH Vessels of the base of the tongue

The lymph vessels of the base of the tongue all drain to the medial retropharyngeal lymph node. Some emerge through the M. hyoglossus (Figure 14: 5, 5), while others emerge at its caudodorsal border (Figure 14: 4’) and continue to travel as 2 to 3 vessels over the pharyngeal muscles to the aforementioned lymph node. Other lymph vessels of the base of the tongue also initially run from the base of the tongue, under the mucous membrane of the pharynx, and penetrate the pharynx muscles: these lymph vessels either emerge through the M. keratopharyngeus (Figure 14: 4’’), or between it and the M. thyropharyngeus (Figure 14: 4), and then run directly to the retropharyngeal lymph node. In most cases, 2 to 3 of the lymph vessels of the base of the tongue demonstrate this behaviour.

d. LYMPH Vessels of the individual muscles of the tongue and hyoid bone

The lymph vessels of the muscles of the tongue and hyoid bone (M. mylohyoideus, M. geniohyoideus, M. genioglossus, M. styloglossus, M. hyoglossus, M. jugulohyoideus, M. stylohyoideus and M. hyothyroideus) drain to the medial retropharyngeal lymph node. Additionally, some of the lymph vessels of M. mylohyoideus drain to the mandibular lymph nodes (see Figures 14 and 15).

The lymph vessels of M. mylohyoideus (Figures 14, 15: a) drain into the mandibular and the medial retropharyngeal lymph nodes. These are tiny lymph vessels that emerge on the outer side of the muscle and then either drain directly to a ventral mandibular lymph node (usually 2 lymph vessels) or run along the M. hyothyroideus and the pharyngeal muscles to drain into the medial retropharyngeal lymph node (usually 1 lymph vessel).

The lymph vessels of the M. geniohyoideus (Figure 14: b) drain to the medial retropharyngeal lymph node (Figure 14: u). They emerge either at the dorsal edge of the muscle or in its vicinity. Some of the vessels run over the lateral side of the M. hyoglossus, and some run over its medial side, and from there over the pharyngeal muscles to drain into the medial retropharyngeal lymph node.

The lymph vessels of the M. genioglossus (Figure 14: c) drain to the medial retropharyngeal lymph node (Figure 14: u). They emerge from both the cranial aspect and middle one-third of the muscle on its lateral side and run between it and the M. hyoglossus aborally, where they merge to form 1 to 3 large, network-forming lymph vessels that run over the pharyngeal muscles into the aforementioned lymph node.

Three to 4 lymph vessels emerge from the M. styloglossus (Figure 14: e), which drain to the medial retropharyngeal lymph node (Figure 14: u). Some may emerge on the medial side of the muscle, some on the ventral border, and occasionally some on the lateral side of the muscle near its ventral border, travelling from the rear (aboral) half of M. styloglossus over the pharyngeal muscles, directly to the medial retropharyngeal lymph node. The lymph vessels emerging from the front (oral) half of the muscle usually cross the medial side of the M. hyoglossus, often forming large, orally turned loops.

The lymph vessels of the M. jugulohyoideus and M. stylohyoideus run as 1 to 2 vessels directly on the pharyngeal musculature into the medial retropharyngeal lymph node.

The lymph vessels of the M. hyoglossus (Figure 14: d) emerge on both of its surfaces and usually merge to form 1 small lymph vessel, which runs over the pharyngeal musculature to drain into the medial retropharyngeal lymph node (Figure 14: u).

Three to 4 small lymph vessels emerge from both surfaces of the M. hyothyroideus (Figure 14: p), and run directly dorsally to the medial retropharyngeal lymph node (Figure 14: u).