Facial vein
It commences at the side of the root of the nose and is a direct continuation of the angular vein where it also receives a small nasal branch.From its origin it runs obliquely downward and backward, beneath the zygomaticus major muscle and zygomatic head of the levator labii superioris, descends along the anterior border and then on the superficial surface of the masseter, crosses over the body of the mandible, and passes obliquely backward, beneath the platysma and cervical fascia, superficial to the submandibular gland, the digastricus and stylohyoideus muscles.Thrombophlebitis of the facial vein, (inflammation of the facial vein with secondary clot formation) can result in pieces of an infected clot extending into the cavernous sinus, forming thrombophlebitis of the cavernous sinus.Infections may spread from the facial veins into the dural venous sinuses.[2] This article incorporates text in the public domain from page 645 of the 20th edition of Gray's Anatomy (1918)