DRAINAGE AREAS OF THE SKULL 141 



central and lateral foramina of the basi-sphenoid bone, 

 with the foramen magnum of the occipital bone, constitute 



FIG. 57. EXTERNAL BASE OF THE SKULL SHOWN IN FIGURE 56. (A.T.) \. 



i, palate plate of the superior maxillary bone; 2, palate plate of the palate bone; 

 3, anterior palatine canal ; 4, is placed outside the posterior palatine canal, inside 

 the tuberosity of the superior maxilla, and in front of the smaller posterior pala- 

 tine canals ; 5, inner surface of the external pterygoid plate ; 6, is placed within 

 the posterior opening of the right nasal fossa on the internal pterygoid plate ; 7, 

 vomer ; X , posterior opening of the pterygo-palatine canal in front of the fora- 

 men lacerum ; 8, spheno-maxillary fissure leading into the orbit : 9, foramen 

 spinosum ; 10, foramen ovale ; 1 1 , placed on the apex of the petrous bone, between 

 the foramen lacerum and the inferior opening of the carotid canal ; 12, jugular 

 foramen; 13, articular eminence of the temporal bone; 14. external auditory 

 meatus ; 15, glenoid fossa in tront of the fissure of Glaser ; 16, tympanic plate or 

 posterior part of the glenoid fossa, close to the styloid process, behind which is 

 seen the stylo-mastoid foramen ; 17, mastoid process, and to its inside the digastric 

 and occipital grooves; 18, basilar process of the occipital bone, and in front the 

 mark of the still incomplete union with the body of the sphenoid bone ; 19, condyle 

 of the occipital bone ; 20, is placed in the foramen magnum, and points to the 

 inner opening of the anterior condylar foramen ; 21, posterior condylar foramen ; 

 22, jugular process of the occipital bone ; 23, external occipital crest running 

 down from the protuberance ; 24, superior curved line of the occipital bone ; 25, 

 26, inferior curved line. 



the main sewers, so to speak, through which the cerebral 

 lymph circulation obtains a regulated and safeguarded 



