The posterior auricular artery is a small artery and arises from the external carotid artery, above the Digastric muscle and Stylohyoid muscle, opposite the apex of the styloid process. It ascends posteriorly beneath the parotid gland, along the styloid process of the temporal bone, between the cartilage of the ear and the mastoid process of the temporal bone along the lateral side of the head. The posterior auricular artery supplies blood to the scalp posterior to the auricle and to the auricle itself. [ http://en.wikipedia.org/wiki/Posterior_auricular_artery ]