LATERAL REGION OF THE SKULL. 



85 



Upon the inner or cerebral surface of this region is a shallow groove, 

 extending along the middle line from before backwards, for the superior 



Fig. 39.' 



Fig. 40.f 



longitudinal sinus ; on either side of this groove are several small fossa* 

 for the Pacchionian bodies, and further outwards, digital fossse correspond- 

 ing with the convexities of the convolutions, and numerous ramified mark- 

 ings for lodging the branches of the arteria meningea media. 



The LATERAL REGION of the skull is divisible into three portions ; tem- 

 poral, mastoid, and zygomatic. 



The temporal portion, or temporal fossa, is bounded above and behind 

 by the temporal ridge, in front by the external angular process of the 



* A front view of the skull. 1. The frontal portion of the frontal bone. The 2, im- 

 mediately over the root of the nose, refers to the nasal tuberosity ; the 3, over the orbit, 

 to the supra-orbital ridge. 4. The optic foramen. 5. The sphenoidal fissure. 6. The 

 spheno-maxillary fissure. 7. The lachrymal fossa in the lachrymal bone, the com- 

 mencement of the nasal duct. The figures 4, 5, 6, 7, are within the orbit. 8. The 

 opening of the anterior nares, divided into two parts by the vomer; the number is 

 placed upon the latter. 9. The infra-orbital foramen. 10. The malar bone. 11. The 

 symphisis of the lower jaw. 12. The mental foramen. 13. The ramus of the lower 

 jaw. 14. The parietal bone. 15. The coronal suture. 16. The temporal bone. 17. 

 The squamous suture. 18. The upper part of the great ala of the sphenoid bone. 19. 

 The commencement of the temporal ridge. 20. The zygoma of the temporal bone, 

 assisting to form the zygomatic arch. 21. The mastoid process. 



[The cerebral surface of the base of the skull. 1. One side of the anterior fossa; the 

 number is placed on the roof of the orbit, formed by the orbital plate of the frontal bone. 

 2. The lesser wing of the sphenoid. 3. The crista galli. 4. The foramen caecum. 

 5. The cribriform lamella of the ethmoid. 6. The processus olivaris. 7. The foramen 

 opticum. 8. The anterior clinoid process. 9. The carotid groove upon the side of the 

 sella turcica, for the internal carotid artery and cavernous sinus. 10, 11, 12. The 

 middle fossa of the base of the skull. 10. Marks the great ala of the sphenoid. 1J. 

 The squamous portion of the temporal bone. 12. The petrous portion of the temporal. 

 13. The sella turcica. 14. The basilar portion of the sphenoid and occipital bone 

 (clivus Blumenbachii). The uneven ridge between Nos. 13, 14, is the dorsum ephippii, 

 and the prominent angles of this ridge the posterior clinoid processes. 15. The fora- 

 men rotundum. 16. The foramen ovale. 17. The foramen spinosum ; the small irre- 

 gular opening between 17 and 12 is the hiatus Fallopii. 18. The posterior fossa of me 

 base of the skull. 19, 19. The groove for the lateral sinus. 20. The ridge upon the 

 occipital bone, which gives attachment to the falx cerebelli. 21. The foramen magnum. 

 22. The meatus auditorius internus. 23. The jugular foramen. 



8 



