ANATOMY IN A NUTSHELL. ■>•>•> 



etal suture, (5) squamo-parietal suture, (6) squamo-sphenoidal suture. 



The stephanion is the point where the coronal suture meets the temporal 

 ridge. 



The pterion is the point where the parietal, frontal, squamous portion of 

 the temporal, and the greater wing of the sphenoid meet. 



The temporal fossa is deep and concave anteriorly, but convex posteriorly. 

 It is marked by grooves which lodge branches of the deep temporal arteries. 

 The Temporal muscle fills this fossa. 



The zygomatic fossa is bounded anteriorlyby the tuberosity of thesuperior 

 maxillary bone, posteriorly by the eminentia articularis and the posterior bor- 

 der of the external pterygoid process, superiorly by the pterygoid ridge which 

 is on the outer surface of the greater wing of the sphenoid hone and separates 

 this fossa from the temporal fossa, interiorly by the alveolar border of the super- 

 ior maxillary bone, externally by the zygomatic arch and the ramus of the lower 

 jaw, internally by the external pterygoid plate. The internal maxillary artery, 

 the inferior maxillary nerve ami its branches, the External pterygoid muscle. 

 the Internal pterygoid muscle, and the lower pan of the Temporal muscle are 

 situated in this fossa. The spheno-maxillary fissure ami the pterygo-maxillary 

 fissure are at the superior and internal part of this fossa. 



The spheno-maxillary fissure, which opens into the outer and back part 

 of the orbit, is horizontal in direction and is formed by the lower border of the 

 orbital surface of the greater wing of the sphenoid superiorly, by the external 

 border of the orbital surface of the superior maxillary bone and a small pari of 

 the palate bone inferiorly; by a small part of the malar bone externally; and it 

 joins the pterygo-maxillary fissure at right angles internally. By means of 

 this fissure the orbit communicates with the temporal fossa, zygomatic fossa, 

 and the spheno-maxillary fossa. The superior maxillary nerve and it > orbital 

 branch, the inferior orbital vessels, and the ascending branches from Meckel's 

 ganglion (spheno-palatine) are transmitted by this fissure. 



The pterygo-maxillary fissure passes at light angles from the inner ex- 

 tremity of the spheno-maxillary fissure and is therefore vertical in direction. 



It is formed by the separation of the superior maxillary bone from the 

 pterygoid process of the sphenoid bone and is shaped like the letter \ . It 

 transmits the branches of the internal maxillary artery and connects the spheno- 

 maxillary fossa with the zygomatic fossa. 



The spheno-maxillary fossa is situated beneath the apex of the orbit where 

 the spheno-maxillary fissure joins the pterygo-maxillary fissure. It is bounded 

 by the under surface of the body of the sphenoid bone and orbital process of 

 the palate bone superiorly, by the superior maxillary bone anteriorly, by the 

 anterior surface of the base of the pterygoid process and lower part of the anter- 

 ior surface of the greater wing of the sphenoid bone posteriorly, by the vertical 

 plate of the palate internally. The sphenoidal fissure, the spheno-maxillary 

 fissure, and pterygo-maxillary fissure open into it. The orbital fossa, nasal 

 fossa, and the zygomatic fossa, and the cavity of the cranium communicate with 

 this fossa. The foramen rotundum superiorly, the vidian foramen belo^ and 

 internal to the foramen rotundum, and the pterygopalatine foramen open on 



