i 4 APPLIED ANATOMY. 



the veins of Galen, and the blood from the falx through the inferior longitudinal 

 sinus. This latter is usually very small and sometimes almost lacking, the blood in 

 that case passing upward to empty into the superior longitudinal sinus. 



The cavernous sinus,- one on each side, is a large, irregular space on. the side 

 of the body of the sphenoid bone. It runs from the sphenoidal fissure in front to 

 the apex of the petrous portion of the temporal bone behind. In front it is continu- 

 ous with the ophthalmic vein, and receives the sphenoparietal sinus which brings the 

 blood from the diploe ; behind it communicates with the superior and inferior petrosal 

 sinuses. The two sinuses communicate across the median line around the pituitary 

 body, forming the circular sinus, and across the basilar process, forming what is 

 sometimes called the transverse sinus, but which is more correctly described as a 

 plexus of veins. 



The cavernous sinus has embedded in its outer wall the third and fourth nerves 

 and the ophthalmic branch of the fifth. Farther below and to the outer side of the 

 sinus are the superior and inferior maxillary or mandibular branches of the fifth 



3rd nerve 

 4th nerve 



Ophthalmic branch of 5th nerve 

 6th nerve 



Superior maxillary nerve 



Inferior maxillary (mandibular) nerve 



Internal carotid artery 



FIG. 20. Transverse section of the right cavernous sinus, showing the position of the nerves and 

 internal carotid artery (from a dissection). 



nerve. Within the sinus and toward its lower and inner portion, is the internal 

 carotid artery. It is surrounded by the blood-current. Between the carotid artery 

 and outer wall of the sinus runs the sixth nerve, held in place by fine, trabecular, 

 fibrous, bands which pass from side to side in the cavity of the sinus. 



The cavernous sinuses are sometimes torn in fractures of the base of the 

 skull, resulting in a traumatic communication between the carotid artery and the 

 sinus. The .-cavernous sinus is not infrequently torn in attempting the removal 

 of the Gasserian ganglion, particularly if its ophthalmic branch is attacked. Its 

 interior is not one large cavity, but is subdivided by fibrous septa, which pass 

 from side to side. It is sometimes the seat of thrombosis and infection, which 

 may reach it through the ophthalmic vein in front. 



FRACTURES OF THE SKULL. 



Fractures of the skull are almost always produced by violent contact of the skull 

 with some solid body. In some cases the fracture is produced by a blow from a 

 moving body, as when a person is struck by a club. In others, the skull is moving 

 and strikes a body at rest, as when a person falls and strikes the head on a pave- 

 ment. It is not necessary to discuss in detail the mechanism of fractures of the skull; 

 it is sufficient to state that nearly all fractures start from the point of impact and 

 radiate to distant regions. The effect of fracturing blows on the skull of a child is 

 different from their effect on the skull of an adult. 



Fractures of the Skull in Children. A child's skull is thin and weak, and 

 while, to a certain extent, fragile is more flexible than that of an adult. It is on this 

 account that blows are more liable to expend their force locally, at the point of impact, 

 and not produce fractures at a distance. Therefore, it follows that fractures of the 

 base are rare in children in comparison with fractures of the vault. Extensive 

 fissured fractures are also rare. A blow will crush the skull of a child at the point 

 of impact, much as an egg-shell is broken at one spot by hitting it with a knife 

 handle. A marked example of this was seen in the case of a small boy who, 



