H4 PRACTICAL ANATOMY. 



fossae it is thin. It is continuous with the mucous membrane of all the cavities 

 with the nasal fossae communicante. 



Name the arteries that supply the nasal fossa. 



1. The anterior and posterior ethmoidal supply the roof, outer wall, and 

 upper half of the septum. These are branches of the ophthalmic, and leave the 

 orbital cavity by the anterior and posterior ethmoidal foramina. The companion 

 veins have like name, and are tributary to the ophthalmic vein. Infection in this 

 region, then, might extend along the ophthalmic vein to the cavernous sinus, 

 since this vein has no valves. 



2. The spheno-palatine supplies the lower half of the septum, the turbinals, 

 the meatuses, the frontal sinuses, and the antra. The companion veins of these 

 arteries are confluent to the pterygoid plexus on the inner side of the internal 

 pterygoid muscle ; the veins take the same name as the arteries. The pterygoid 



Frontal sinusec 



MIDDLE TURBINAL 

 BONE 



NASAL SEPTUM 



RIGHT ANTRUM 



INFERIOR TURBINAL 

 BONE 



FIG. 76. TRANSVERSE SECTION PASSING THROUGH THE NASAL Foss^: AND ANTRA AT THE 

 POSTERIOR EXTREMITY OF THE MIDDLE TURBINAL BONE. (Seen from the front.) 



plexus communicates with the cavernous sinus by the Vesalian vein. Infection 

 from this region may reach the sinus, since the Vesalian has no valves. 



3. The descending palatine and Vidian arteries, branches of the internal max- 

 illary, supply the nasal fossae. 



What can you say of the nasal mucous membrane in relation to nose bleeding , 

 and in what way may a violent hemorrhage from the nose abort cerebral apoplexy ? 



The venous blood in the mucous membrane of the nose communicates with 

 the superior longitudinal sinus, in the falx cerebri, by an emissary vein which 

 passes through the foramen caecum in front of the crista galli. The nasal mucous 

 membrane is very vascular and quite loosely attached, a condition favoring easy 

 rupture of its vessels. In cerebral congestion of the face the ocular and nasal 

 mucous membranes become engorged, on account of their communication with 

 the sinuses. On account of its lax attachment the vessels of the nasal mucous 



