78 ATLAS AND TEXT-BOOK OF HUMAN ANATOMY. 



Fig. ioi. — View of the lateral wall of the right nasal fossa, the nasal septum having been removed (A). 

 Fig. 102. — View of the lateral wall of the right nasal fossa, the middle turbinated bone having been 

 removed (i). 

 In these figures the frontal bone is violet, the lachrymal pink, the ethmoid orange, the maxilla yellow, the 

 palatine blue, the sphenoid green, and the other bones white. 



Fig. 103. — The left pterygopalatine fossa seen from the side, after the removal of the zygomatic bone (A). 

 The maxilla is yellow, the palate bone blue, the sphenoid green, and the zygomatic and temporal bones white. 



(d) The hiatus semilunaris (Fig. 101), in the middle meatus in the region of the infundib- 

 ulum, which leads to the orifice of the frontal sinus (Fig. 102) and to the openings of the anterior 

 ethmoidal cells; the middle meatus also contains the orifice of the maxillary sinus. 



(e) The openings of the middle and posterior ethmoidal cells in the superior meatus. 



(/) The upper and posterior portion of the nasal cavity contains the sphenoethmoidal 

 recess, the orifice of the sphenoidal sinus (Fig. 102), the small posterior ethmoidal foramen 

 (leading into the orbital cavity and transmitting the vessels of the same name), and the spheno- 

 palatine foramen (Fig. 102), which accommodates the ganglion and vessels of the same name 

 and communicates with the pterygopalatine (sphenomaxillary) fossa. 



THE ROOF OF THE ORAL CAVITY, THE HARD PALATE. 



The roof of the oral cavity (Fig. 100) is formed by the hard palate. It is a markedly concave 

 elliptical bony plate, composed of the palatine processes of the maxillae and of the horizontal 

 portions and of part of the pyramidal processes or tuberosities of the palate bones. It presents 

 in the median line the median palatine suture, upon which a bony swelling, the torus palatinus, 

 is occasionally observed; it also contains the transverse palatine suture and sometimes the 

 remains of the incisive suture. At the anterior extremity of the median suture is situated the 

 single incisive foramen, by which the bony oral cavity communicates with both bony nasal 

 fossae; posteriorly in the horizontal plate of each palate bone is the greater palatine foramen, 

 and the pyramidal process contains the lesser palatine foramina (inconstant). All these foramina 

 are the orifices of the pterygopalatine canal. 



THE PTERYGOPALATINE FOSSA. 



The pterygopalatine .or sphenomaxillary fossa (Fig. 103) lies between the anterior surface 

 of the pterygoid process of the sphenoid bone, the perpendicular portion of the palate bone, and 

 the posterior extremity of the maxilla. It is funnel-shaped and is continued directly downward 

 into the pterygopalatine canal, which is bounded by the same three bones. It opens out supe- 

 riorly into the inferior orbital (sphenomaxillary) fissure which communicates with the orbit 

 and externally the pterygomaxillary fissure connects the pterygopalatine with the infratem- 

 poral fossa. 



Opening into the pterygopalatine fossa are the foramen rotundum, by which it communicates 

 with the cranial cavity, the pterygoid canal, which passes horizontally backward in the root of 

 the pterygoid process, and the sphenopalatine foramen, leading into the nasal cavity. The 

 fossa contains the sphenopalatine ganglion of the maxillary nerve as well as arteries and veins. 



