322 CHORD ATA. 



obliquus superior with its trochlear nerve, and the rectus 

 superior^ externus and inter?ius muscles. The rectus ex- 

 ternus is suppHed by the minute sixth (abducens) nerve 

 which is not easily seen. The other four are supplied by 

 the third or oculomotor. (For list of these muscles see 

 page 410.) 



Running over the bases of the upper eye-muscles is a 

 long nerve called the ophthalmicus superjicialis. It enters 

 the orbit posteriorly and leaves it anteriorly to pass for- 

 wards to the rostrum. It is a compound nerve formed of 

 the fifth and seventh. Entering the orbit and leaving it 

 by the same foramina as this nerve is another, called the 

 ophthalmicus profundus. It, however, lies below the three 

 upper eye-muscles (i.e,^ rectus superior, obliquus superior, 

 and rectus internus), though well above the other eye- 

 muscles and the optic nerve. 



A very little dissection between the auditory capsule and 

 the mandibular muscle will reveal a large nerve, the hyo- 

 mandibular, an important branch of the seventh nerve 

 which can be traced to ampullae or sensory tubes in the 

 skin and backwards to the front of the auditory capsule. 

 It gives off a large external mandibular round the outer 

 folds of the mandibular muscle and other branches which 

 are the recurrent facial^ internal mandibular^ facial proper 

 and hyoidean. 



If the eye be now carefully removed by cutting the 

 eye-muscles and optic stalk and the orbit be cleared, 

 a number of deeper nerves are brought into view. The 

 outer buccal (VII.) is a large branch easily found lying 

 between the olfactory capsule and the mandibular muscle. 

 It runs across the floor of the orbit and outwards to 

 ampullae. Very deep in the orbit, below the ophthalmicus 

 profundus, lies the inner buccal (VII.) passing to the roof 

 of the mouth. In the angle formed by the two buccals lie 

 the maxillary (V.) to the upper jaw and the mandibular (V.) 

 to the lower jaw. 



Lastly, in front of the spiracle is d^ palatine (VII.) with a 

 branch, the prespiracular (Vll.).t 



* This nerve is also sometimes termed the chorda tyvipani. 

 t These lie very deep on the actual roof of the mouth. 



