228 HUMAN ANATOMY. 



the minute pterygo-palatitie canal, formed by the palate and sphenoid bones. The 

 spheno-palatine foramen opens through the inner wall into the nasal cavity. The 

 fossa opens below into the posterior palatine canal. 



The Roof of the Mouth. — This comprises the hard palate and the inner 

 aspect of the alveolar process. The proportions, as stated elsewhere (page 229), 

 vary ; as a rule, the broad palate is less vaulted than the narrow one. The oral 

 roof presents the orifices of three canals,— the anterior^ and the two posterior 

 palatine. The first is situated in the mid-line in frortt, the others at the outer 

 posterior angles. The palatine grooves for the anterior palatine nerves and accom- 

 panying blood-vessels extend forward from the posterior palatine foramina. Be- 

 hind, but close to, the latter are the orifices of the accessory palatine canals. 

 The inner side of the alveolar process is rough except opposite the second and 

 third molar teeth, and the same is true of that part of the palate made by the superior 

 maxillae. An occasional swelling, the torns palatinus, is in the mid-line at the 

 junction of the superior maxillae. Internal to the first molar is a ridge with the 

 groove outside of it at the lateral border of the maxilla. The line separating the 

 superior maxillae from the horizontal plates of the palate bones has a forward curve 

 in the middle in nearly three-quarters of the cases. It is about straight in some 

 twenty per cent, and curved backward in the rest. The fissures are not always 

 symmetrical.^ 



The Architecture of the Face. — With the exception of the lower jaw, the 

 structure of the face is extremely light. It is subject to no strain save through that 

 bone, and to some extent through the action of the tongue on the palate ; it has, 

 however, to be protected against occasional violence. There are certain strong and 

 strengthening regions. The hard palate is strong throughout, except at the hind 

 part, and especially strong back of the incisors. Some strength is gained by a 

 thickening just outside of the nasal opening above the canine teeth, running up 

 into the ridge in front of the lachrymal groove. The root of the nose is also very 

 thick. The face is considerably strengthened through the malar bone and its con- 

 nections, especially with the robust external angular process. A little support is 

 probably given to the back of the jaw through the pterygoids. 



ANTHROPOLOGY OF THE SKULL. 



There are certain terms and measurements which should be known, especially as some of 

 them come into practical use in the surgery of the skull. 



Points on the Surface of the Skull. — (See also Fig. 265, page 241.) 



Alveolar point, the lowest point in the mid-line of the upper alveolar process. 



Asterion, the lower end of the lambdoidal suture ; three sutures diverge from it like rays. 



Auricular point, the centre of the external auditory meatus. 



Basion, the anterior point of the margin of the foramen magnum. 



Bregma, the anterior end of the sagittal suture. 



Dacryofi, the point of contact of the frontal, maxillary, and lachrymal bones. 



Glabella, the region abo\e the nose between the superciliary eminences. 



Glenoid point, the centre of the glenoid fossa. 



Gonion, the outer side of the angle of the lower jaw. 



Ittion, the external occipital protuberance. 



Lambda, the posterior end of the sagittal suture. 



Malar poitit, the most prominent point of that bone. 



Mental point, the most anterior point of the symphysis of the lower jaw, 



Nasion, the point of contact of the frontal bone with both nasals. 



Obelion, tlie sagittal suture in the region of the parietal foramina. 



Occipital point, the most posterior point in the mid-line. (It is above the protuberance. ) 



Ophryon, the point of intersection of the median line with a line connecting the tops of the 

 orbits. 



Opisthion, the posterior point of the margin of the foramen magnum. 



Pterion, the region where the frontal, the great wing of the sphenoid, the parietal, and 

 the temporal bones almost meet. (As, in fact, they very rarely do meet, the term is a vague 

 one.) 



^ For the description of this canal, see under Superior Maxilla (page 201). 

 ' Stieda : Arch, fiir Anthropol., 1893. 



