Medial retropharyngeal lymph nodes

The medial retropharyngeal lymph nodes are located on the dorsomedial pharyngeal wall, medial to the stylohyoid muscle or its equivalent. Generally voluminous, they are present in reduced numbers in all species (except humans), in the form of a main, constant lymph node and sometimes one or more small, secondary, variable lymph nodes.

Together with the lateral retropharyngeal lymph nodes, they drain all the deep planes of the head (including the pharynx, base of the tongue, tonsils, caudal part of the nasal cavities) and the cranial part of the neck.

Variations:

• Horse: there are 20 to 35 of them, placed along the external carotid artery, between the pharynx, the guttural pouch and the angular bundle of the digastric muscle. They drain the guttural pouches.

• Cows and carnivores: it is single, sometimes double.