ANATOMY OF THE ANTERIOR SKULL BASE
The anterior skull base separates the anterior cranial fossa superiorly from the paranasal sinuses and orbits below.
The boundaries of the anterior skull base are anterolaterally the frontal bones,
inferiorly the ethmoid and frontal sinuses,
orbit and orbital canals.
Superiorly the frontal lobes and the first cranial nerve and the boundaries with the central skull base are the lesser wing of sphenoid bone and planum sphenoidale.
In the anterior skull base we have to identify different landmarks on imaging.
The cribiform plate,
the lateral lamella and the orbital roof,
on MRI we can identify the olfactory bulbs.
Fig. 1: Sagittal CT image. Anatomic landmarks for endoscopic skull surgery
Fig. 2: Coronal CT and Coronal T2W MRI. Anterior Skull base anatomy
There are five entry points in the skull base for anterior skull base minimally invasive surgery,
it is important to become familiar with the anatomy,
to select the best entry point,
depending on the pathology.
Fig. 3: Sagittal CT image with showing the entry points of surgical corridors for endoscopic skull surgery
•Transplanum sphenoidale 3
ANATOMY OF THE CENTRAL SKULL BASE
The central skull base makes up the floor of the middle cranial fossa.
It is composed of the sphenoid and temporal bone anterior to the petrous ridge.
It can be divided into midline sagittal,
parasagittal and lateral compartments.
It is separated from the anterior skull base by a line that follows the tubercullym sella,
the anterior clinoid processess,
the posterior margin of the lesser sphenoid wings,
and the anterior and superior rim of the greater sphenoid wings.
It is separated posteriorly from the posterior skull base by a line that follows the dorsum sella and posterior clinoid processes and petrous ridges laterally.
The central skull base might be divided in compartments: midline sagittal (MLS),
parasagittal (PS) and lateral (L) compartments.
Fig. 4: Axial CT demonstrating the anatomic landmarks in central skull base
Fig. 5: Coronal T2W MRI demonstrating the anatomy of central skull base