26 



10. The TIL, IV., and VI. nerves and the muscles of the eye. 



a. The oculo-motor (III.) sending branches to — 



(a) The levator bulbi which extends from the side of the skull under 



the eyeball to the upper jaw, giving off a few fibres to act as a 

 depressor of the lower eyelid. 



(b) The superior, inferior, and internal recti which arise from the inner 



angle of the orbit and are inserted into the sclerotic. 



(c) The inferior oblique, which extends from the palatine bone to the 



under surface of the sclerotic, 



(d) The retractor bulbi which encloses the optic nerve. 



6. The pathetic (IV.) supplying the superior oblique which extends from 

 the palatine to the upper surface of the sclerotic. 



c. The abducens (VI.) supplying the external rectus and the retractor of 



the bulb. 



d. Make a sketch showing the optic nerve, the eyeball, and the muscles 



inserted into the sclerotic. 



11. The Trigenimal (V.) which passes from the cranium in front of the auditory 



capsule and divides into — 



a. The ophthalmic branch which extends forwards under the superior 



rectus muscle to communicate with the IV. nerve and supply the 

 Harderian gland, nasal mucous membrane and the skin in the region 

 of the nasal capsule. 



b. The maxiUary branch which runs forwards under the eyeball to reach 



the lower eyelid and the skin covering the upper jaw. 



c. The mandibular branch which, at first continuous with the maxillary 



portion, bends round the inner surface of the upper jaw to reach and 

 extend along the outer surface of the mandible. Look for branches 

 to the temporal and pterj'goid muscles and the skin covering the 

 lower jaw. 

 The ganglion (Gasserian) on the root of the V. nerve with which the VI. 

 and VII. nerves and the sympathic are connected, lies in the foramen 

 of the pro-otic bone. 



12. The facial nerve (VII.) which leaves the skull immediately behind the tri- 



geminal and divides into — 



(a) The palatine branch which runs forwards under the orbit, and is dis- 



tributed partly to the roof of the mouth and partly along with the 

 mandibular branch of the V. td the front of the palate and the outer 

 aspect of the mandible. 



(b) The hyomandibular branch which runs outwards over the auditory 



capsule and columella to the angle of the mouth, where it divides, one 

 portion extending towards the anterior comu of the hyoid, the other 

 running along the inner surface of the mandible to reach the sym- 

 physis. 



13. The auditory nerve (VIII.) which enters the auditory capsule to terminate 

 in the internal ear. For the anatomy of the auditory organ, see the 

 " Dissection of the Skate." 



