On the facial artery of the raccoon dog (Nyctereutes procyonoides viverrinus Temminck).

Detailed observations were made of the facial artery in 20 raccoon dogs (Nyctereutes procyonoides viverrinus Temminck) utilizing the plastic injection method. The findings obtained were discussed in comparison with the facial artery of carnivorae. The facial artery diverged anterolaterally from the external carotid artery independently at a position between the origins of the lingual and the posterior auricular arteries when the external carotid bent laterally in front of the tympanic bulla. This artery, immediately after giving off the styloglossal branch, passed forwards superomedial to the digastricus muscle and medial to the insertion of the pterygoideus medialis muscle up to the posterolateral end of the mylohyoideus muscle, where the submental artery was derived. The submental ran forwards, giving off the digastric, the mylohyoid, the sublingual and the cutaneous branches, down to the posterolateral end of the intermandibular symphysis, where it anastomosed with the opposite fellow. The facial artery bent inferolaterally and passed laterally giving off the pterygoid and the inferior masseteric branches, and then emerged out onto the face through the facial vascular notch located inferoanterior to the angular process, which was extremely well developed in this species. The main stream of the artery ran anterosuperiorly at about 40 degrees to the horizontal plane along the anterior margin of the masseter muscle, since the notch was located on a projected level posterior to the middle of the zygomatic arch, giving rise en route to the anterior masseteric, the mandibular marginal, the buccal and the cutaneous branches. The artery finally divided into the inferior and superior labial arteries at the inferior margin of the mandibular origin of the buccalis muscle in the angle of the mouth. The facial artery of the raccoon dog was thus similar in its origin to that in the dog, cat and lion, but notably different in the short course of its submandibular region, and the nearly horizontal passage of the main route in the face, without the mandibular glandular branch. Additionally an extremely well developed angular process, a submandibular lobe and fairly posterior position of the vascular notch were found.