THE CRANIAL SINUSES 113 



foramen caecum of the ethmoid, through which it may 

 communicate with the veins of the nasal mucous membrane. 

 Owing to this communication, epistaxis may occur in children, 



FIG. 55. The Cranial Blood Sinuses. The left half of the skull and 

 the left cerebral hemisphere have been removed. 



A . Anterior cerebral artery. 



B. Great cerebral vein (of Galen). 



C. Superior sagittal sinus. 



D. Inferior sagittal sinus. 



E. Straight sinus. 



F. Superior petrosal sinus. 



G. Transverse (lateral) sinus. 



a. Scalp. 



b. Cut edge of skull. 



c. Mastoid process. 



d. Styloid process. 



e. Foramen ovale. 

 f. Maxillary nerve. 



. Frontal air sinus. 

 h. Lateral pterygoid lamina. 

 j. Mandibular (glenoid) fossa. 

 /. Maxilla. 



1. Falx cerebri. 



2. Tentorium cerebelli. 



3. Optic nerve. 



4. Cut edge of dura mater. 



5. Mandibular nerve. 



6. Tuberosity of maxilla. 



7. Ophthalmic nerve. 



8. Corpus callosum. 



9. Pineal body. 

 Mid- brain. 



following an increase of intra-cranial tension such as ac- 

 companies a fit of temper. The foramen caecum is usually 

 patent in young children, but it may become closed at a 

 later stage. 



