LYMPHOCENTERS OF THE HEAD AND NECK OF THE DONKEY (EQUUS ASINUS)*

The present study was carried out on ten donkeys injected with 1% Evans blue. The drainage area of each lymph node had the same pattern like that of the horse. The lymphocenters of the head include the mandibular, parotid and retropharyngeal. The mandibular lymphocenter of both sides form V-shaped mass. Its efferents end in the medial retropharyngeal and cranial deep cervical lymph nodes. Moreover and unlike that reported inthe horse, the parotid lymph nodes are situated ventral and dorsal to the tempromandibular joint. The efferent of the parotid terminates in the lateral retropharyngeal lymph nodes. The effer ents of the retropharyngeal lymphocenter join the cranial deep cerical lymph nodes as well as the tracheal trunks. The lymphocenters of the neck are the superficial and deep cervical. The efferent vessels of the superficial cervical lympho center end either in the caudal deep cervical lymph nodes or in the cranial vena cava. The efferent of the cranial deep cervical lymph nodes shares in the formation of the tracheal trunk. The efferent of the caudal deep cervical terminate in the bijugular trunk and the thoracic duct.
The tracheal trunks are formed by the efferents of the cranial deep cervical, retropharyngeal and middle deep cervical lymph nodes. They terminate in the caudal deep cervical lymph nodes.