hyperostosis frontalis interna

Description: overgrowth of bone at the inner table of the frontal bone
* usually bilateral and symmetrical
* chiefly in females> 35 y.o.
* no clinical siginificance
* unknown etiology
* irregular cortical thickening of the frontal area
* spares areas occupied by superior sagital sinus and venous channels
* may be 1 cm or thicker
* occasionaly extends to parietal bones and orbital roofs
* hyperostosis calvariae diffusa:
o variant of HFI: more diffuse thickening of vault (involving both tables)