INTRAPETROUS PART OF FACIAL NERVE 563 



3. A part which occupies that portion of the canalis facialis which runs 



along the medial wall of the tympanic cavity. 



4. A part which extends vertically downwards to the stylo-mastoid 



foramen. 



First Stage. In the internal acustic meatus, the facial 

 nerve runs almost directly laterally in company with the 

 acustic nerve. In this stage of its course it lies in relation 

 to the upper and anterior part of the acustic nerve, and 

 its motor and sensory roots join. At the bottom of the 

 acustic meatus it enters the canalis facialis. 



FIG. 247. Diagram of Intrapetrous part of facial nerve and its connections. 

 (Prof. A. M. Paterson.) 



r. Nerve to stapedius. 2. Chorda tympani. 3. Tympanic plexus. 4. Communication 

 to small superficial petrosal nerve. 5. Ganglion geniculi. 6. Motor part of 

 facial nerve. 7. Sensory part of facial nerve. 8. Acustic nerve. 9. External 

 petrosal nerve. 10. Great superficial petrosal nerve. n. Carotid canal. 12. 

 Carotico-tympanic branch. 13. Carotid plexus. 14. Great deep petrosal. 15. 

 Nerve of pterygoid canal. 16 and 18. Spheno-palatine branches. 17. Maxillary 

 nerve. 19. Spheno-palatine ganglion. 20. External petrosal. 21. Middle 

 meningeal artery. 22. Otk: ganglion. 23 and 24. Branches to auriculo-temporal 

 nerve. 25. Communication to chorda tympani. 26. Posterior division of 

 mandibular nerve. 27. Anterior division of mandibular nerve. 28. Lingual nerve. 

 29. Inferior alveolar nerve. 30. Auriculo-temporal nerve. 31. Tympanic branch 

 of glossopharyngeal. 32. Glossopharyngeal nerve. 33. Vagus. 34. Auricular 

 branch of vagus. 35. Communication from facial to auricular branch of vagus. 

 36. Nerve to digastric (post, belly). 37. Nerve to stylo -hyoid muscle. 38. 

 Posterior auricular nerve. 



Second Stage. The second part of the facial nerve is very 

 short. It runs laterally, with a slight inclination anteriorly, 

 between the vestibule and cochlea, and very soon ends in 

 the swelling termed the ganglion geniculi. 



Third Stage. At the ganglion geniculi, the facial nerve 

 bends suddenly and proceeds posteriorly and slightly 



