various anatomical landmarks including stensen 's duct , the retromandibular vein , the styloid process , the posterior belly of the digastric muscle and more recently an arc 8.5 mm from the posterior border of the mandible have been used to predict the course of the facial nerve and hence divide the parotid into its deep and superficial portions .
C0227458
stensen 's duct
C0030580
parotid