BLOOD-VESSELS AND LYMPHATICS. 



145 



The veins form a dense plexus in the mucous membrane, those in the deeper 

 parts of the membrane being especially large and closely arranged so as almost to 

 approach the structure of a cavernous tissue. This is most largely developed over 

 the whole lower turbinal, the lower and hinder border of the middle turbiual, and 

 the hinder end of the upper turbinal as well as on the lower and hinder part of 

 the septum. A similar dense venous plexus, continuous with that of the nasal 

 fossae, extends around the nasal duct, as far upwards as the lachrymal sac. The 

 trunks leaving the cavity accompany the arteries, the spheno-palatine vein emptying 



eptal branch of ant. ethmoidal 



communicating 

 branch between 

 post, nasal and 

 post, ethmoidal 



naso-palatinc, artery 



1 

 post, nasal artery 



branches of post, nasal branch for inferior concha 

 for the inf. mcatus 



Fig. 165. ARTERIAL SUPPLY TO THE MUCOUS MEMBRANE OP THE LATERAL WALL OF THE NASAL FOSSA. 



(AfterZuckerkancll.) 



itself into the pterygoid plexus ; the ethmoidal veins joining the ophthalmic vein 

 and the veins of the dura mater, and also sending a branch to join the veins of the 

 orbital part of the frontal lobe of the brain (Zuckerkandl), and small veins passing 

 out at the margin of the nares to join the venous plexus of the upper lip. Some 

 small veins also pierce the nasal bone and the ascending process of the superior 

 maxilla to join the commencement of the facial vein. 



The lymphatics are abundant and large. They form a close plexus in the 

 mucous membrane, the branches extending almost to the surface, and a more open 

 plexus of valved vessels nearer the bone. These are in communication with the 

 lymphatic spaces which enclose the branches of the olfactory nerve, and these spaces 

 again communicate with the subdural and subarachnoid spaces of the cranium, so 

 that the lymphatics of the nasal mucous membrane can be injected from the cranial 



VOL. III., PT. 3. L 



