1056 DISSECTION OF THE HEAD AND NECK. 



course, the inferior dental, the middle meningeal giving off the small rnenm- 

 geal artery, the two deep temporal, the pterygoid and other muscular 

 branches : next, more deeply within the pterygoid muscles, the posterior 

 superior dental and the infraorbital branches (p. 354). The chorda tympani 

 nerve is to be dissected upwards to the fissure of Glaser, from its point of 

 junction with the gustatory nerve under cover of the external pterygoid 

 muscle, and the branches of the inferior maxillary nerve are to be traced 

 back to the foramen ovale (p. 605) : the auriculo-temporal nerve will fre- 

 quently be found embracing the middle meningeal artery. The internal 

 pterygoid muscle is to be examined as far as it can be laid bare (p. 181). 

 The auriculo-temporal division of the inferior maxillary nerve is then to be 

 traced to its distribution, and the pinna of the ear is to be dissected so as to 

 show the form and extent of its cartilage, the small muscles on its surface, 

 and the final distribution of its nerves (p. 741). 



7. The Orbit. The dissection of the orbit and the parts pasoing into it 

 may next be proceeded with. Let a vertical cut be made with the saw 

 through the frontal bone, near the inner angle of the orbit, immediately 

 above the fovea trochlearis ; and another from above the ear, downwards 

 and forwards, through the lateral wall of the skull, towards the sphenoidal 

 fissure. Remove the outer part of the malar bone with the bone-nippers, 

 separate carefully with the handle of the knife the periosteum and con- 

 tents of the orbit from the upper and outer walls, and unite the inner 

 saw-cut with the sphenoidal fissure, immediately outside the optic foramen, 

 by means of the chisel ; then, with the bone-nippers, remove the isolated 

 piece of bone so as to unroof the orbit, and afterwards divide the periosteum 

 longitudinally, and reflect it. On the upper surface of the contents of the orbit 

 posteriorly is the fourth nerve, which is to be traced forwards from the cavern- 

 ous sinus where it enters the orbital surface of the trochlearis muscle, and that 

 muscle is to be displayed (pp. 594 and 179). The frontal nerve, occupying 

 the middle of the space, is to be traced back to its origin from the 

 ophthalmic division of the fifth nerve (p. 597). The lachrymal gland is to 

 be exposed (p. 709); and from its posterior border the lachrymal nerve is to 

 be traced back to its origin from the ophthalmic nerve, while at the same 

 lime its malar branch and palpebral distribution may also be seen. The 

 levator palpebrss muscle, and the inferior, external, and internal recti 

 muscles are to be displayed (p. 179), and the ocular surface of each 

 cleared ; when the sixth nerve will be seen ending in the external rectus, 

 and branches of the third in the other three recti muscles. These nerves 

 are now to be traced backwards between the two heads of origin of the 

 external rectus muscle to the cavernous sinus (pp. 593 and 610). Below 

 the superior rectus muscle the nasal nerve, derived from the ophthalmic, 

 will be seen crossing the optic nerve ; it will be followed to the anterior 

 internal orbital foramen, and its infratrochlear branch traced to the lower 

 eyelid ; it is then to be dissected back to its origin, and the long and deli- 

 cate root of the lenticular ganglion sought for on the outer side of the 

 optic nerve. The ophthalmic or lenticular ganglion is on the outside of the 

 optic nerve, and may be most easily found by tracing the short and thick 

 twig which runs into it from the inferior division of the third nerve. In 

 front of the ganglion its ciliary branches may be seen (p. 599). The 

 remainder of the fat is to be removed from the lower part of the orbit ; 

 the distribution of the ophthalmic artery is to be displayed (p. 360) ; and 

 the lower division of the third nerve is to be traced forwards to the 

 inferior rectus and obliquus muscles. By a slight dissection from the front 



