i/w 



'1 





N A S A L F S S JE . 65 



foramen lacerum anterius, and, lying in a groove on the surface of the 

 petrous portion of the temporal bone, takes the name of nervus petrosus 

 su/H-rficialis major, and enters the hiatus Fallopii to join the gangli- 

 fonn enlargement of the facial nerve. 



These branches can hardly be found except by a special dissection. 



Before discarding the piece of bone which the student 

 has just been examining, he should open the carotid canal 

 to see the temporal portion of the internal carotid artery. 

 'he canal can be opened by bone forceps, or by a small 



isel carefully handled. The artery at first ascends, is 

 then directed forward horizontally, and lastly turns upward 

 into the cranium. In the canal it is surrounded by branches 

 from the superior cervical ganglion of the sympathetic 

 nerve ; it gives off a minute branch to the tympanum. 



NASAL FOSSAE. 



To expose the nasal cavities, the saw should be placed at the side 

 of the crista galli, and carried through the nasal and frontal bones to 

 the roof of the mouth ; this separates the portion of skull iuto two 

 halves, leaving the septum nasi attached upon one side. 



The two cavities on either side of the septum of the nose 

 are called the nasal fossae; they communicate with the pha- 

 rynx and face by apertures, called anterior and posterior 

 mires, and also with the sinuses of the frontal, ethmoid, 

 sphenoid, and superior maxillary bones. The septum of the 

 fossae is partly osseous and partly cartilaginous, being 

 formed by the perpendicular plate of the ethmoid bone, the 

 vomer, and the triangular cartilage of the nose. The sep- 

 tum is usually more or less bent to one or the other side. 



On the outer boundary of the nasal fossae will be found 

 the three convoluted spongy or turbinated bones. The two 

 superior are processes of the ethmoid bone, and are known 

 respectively as the superior and middle turbinated bones ; 

 the lower one is an independent bone, called the inferior 

 turbinated bone. These bones overhang spaces called 

 meatuses; they are three in number; the superior meatus 

 is the smallest ; it is overhung by the superior turbinated 

 bone, and occupies nearly the posterior half of the outer 

 aspect of the nasal fossa ; the posterior ethmoidal sinuses 

 open into it in front, and in the dried bone at its posterior 

 part will be found the spheno-palatine foramen, by which 

 the nerves and vessels enter the nose. The middle turbi- 

 nated bone overhangs the middle meatus, which extends 

 nearty the whoie length of the outer wall of the fossa ; it 



6* 



