#skull #cranialfossa #olfactory
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The anterior cranial fossa lodges the frontal lobes of the cerebral hemispheres. Its floor is composed of the portions of the following three bones: sphenoid, frontal and ethmoid.
It is demarcated from the middle cranial fossa by the posterior free border of the lesser wing of sphenoid on each side, and anterior border of the sulcus chiasmaticus in the median
region. At the junction between posterior border of the lesser wing of sphenoid and anterior border of sulcus chiasmaticus, the anterior clinoid process is present.
The anterior cranial fossa presents the following features:
In the median region, from before backward these are:
The Frontal crest which is a vertical crest on the inner aspect of the frontal bone.
Behind the frontal crest is the Foramen cecum.
The next structure on the midline is the crista galli, a bony crest fromed by the perpendicular plate of the ethmoid.
Behind the crista galli is the jugum sphenoidale which is the superior surface of the anterior part of the body of the sphenoid.
On each side of crista galli lies the cribriform plate of the ethmoid which separates the
anterior cranial fossa from the nasal cavity. It possesses a number of small foramina.
At the level of the the suture between the ethmoid and frontal bones we have two foramens: Anterior ethmoidal foramen and posterior ethmoidal foramen.
Just lateral to the anterior part of crista galli is the nasal slit.
If foramen cecum is patent an emissary vein passes from nasal muscosa to the anterior end of superior sagittal sinus.
Through the number of small foramina of the cribriform plate of ethmoid are passing the Olfactory nerves.
The posterior ethmoidal foramen gives passage to the posterior ethmoidal nerve and vessels.
The anterior ethmoidal foramen gives passage to the anterior ethmoidal nerve and vessels. The anterior ethmoidal nerve after arrives in the anterior cranial fossa gives some small branches to the dura mater in this region and then leaves the fossa passing through the nasal slit and thus arriving in the nasal cavity.

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