Lymph Vessels of the Larynx
The lymph vessels of the larynx drain to both the medial retropharyngeal and the cranial cervical lymph nodes. The lymph vessels of the laryngeal mucosa, the cartilages of the larynx, and the internal laryngeal muscles merge to form several small vessels that leave the larynx by 3 different routes (groups A to C, below).
Group A
Two to 3 of the lymph vessels pass through the pharyngeal muscles, usually either between the M. keratopharyngeus and M. thyropharyngeus, or at the angle between these two muscles and the M. hyothyroideus (Figure 16: k), and then run on the pharyngeal muscles to the aforementioned lymph nodes.
Group B
One to 2 other lymph vessels emerge either between the thyroid cartilage and the cricoid cartilage at the ventral margin of the M. cricothyroideus, between it and the M. hyothyroideus, or through the M. hyothyroideus (Figures 14: 9; 16: k’), and run over both surfaces of the M. sternothyroideus, continuing on the pharyngeal muscles towards the medial retropharyngeal lymph node.
Group C
Lastly, 1 to 2 lymph vessels emerge at the caudal edge of the cricoid cartilage, near its plate, and drain to the aforementioned lymph nodes (Figure 16: k’’). If a cranial cervical lymph node is present, then 1 to 2 vessels of this group will additionally drain to it (Figure 16: k’’’).
The lymph vessels of the laryngeal mucosa form very fine networks in and under it. The lymph vessels arising from the networks initially run under the mucosa for varying distances. At the epiglottis, the lymph vessels form abundant networks under the mucosa of both its surfaces. One to 2 lymph vessels emerge from the network on each surface, merging in the aryepiglottic fold to form 1 to 2 vessels, which then pass between M. keratopharyngeus and M. thyropharyngeus, specifically in the gap between these two muscles and the M. hyothyroideus, to the other side (see group A, above).
The lymph vessels of the thyroid cartilage join groups A and B, those of the cricoid cartilage join group C, and those of the arytenoid cartilage join group A. The lymph vessels of both the vocal cord and vocal fold join group A.
The lymph vessels of the external laryngeal muscles (M. hyothyroideus [Figure 23: g] and M. cricothyroideus) as well as the pharyngeal constrictors located on the larynx (M. keratopharyngeus, thyropharyngeus and cricopharyngeus) (Figure 23: f, h) emerge from the surface of these muscles and drain directly to the medial retropharyngeal lymph node (Figure 23: 1).
