In the parasellar region, Anterior Clinoid Process
(ACP) with its supporting structures like Optic Strut (OS), medial part of lesser wing of the sphenoid and roof of the optic canal are certain bony landmarks related to important elements like the cavernous sinus, Internal Carotid Artery (ICA), Optic Nerve (ON) and the pituitary gland.
The lesion was causing thinning and pressure erosion of the posterior wall of maxillary sinus, pterygoid plate, posterior wall of orbit, medial wall of sphenoid on the left side, left lesser wing of sphenoid, and was causing thinning of left anterior clinoid process
McDermott, "Mucocele involving the anterior clinoid process
: MR and CT findings," American Journal of Neuroradiology, vol.
Furthermore, V4 travels along the lateral and superior side walls of sphenoid sinus in a posterior-to-anterosuperior direction and exits medial to the anterior clinoid process
to become intradural segment [9,29].
Pneumatization of anterior clinoid process
was there in 2 (4%) patients; all unilateral.
The supraorbital keyhole approach effectively exposes the frontal lobe base, anterior clinoid process
, canalis opticus, olfactory sulcus, olfactory tract, optic nerve, optic chiasm, oculomotor nerve, anterior communicating artery, anterior cerebral artery A1 segment, pituitary stalk, diaphragma sellae, dorsum sellae, posterior clinoid process, basilar artery apex, posterior cerebral artery P1 segment, superior cerebellar artery proximal, front upper pontine and interpeduncular cistern, anteromedial temporal lobe, internal carotid, middle cerebral artery (M1, M2 segment, and part of M3 segment), anterior choroidal artery, posterior communicating artery; and contralateral carotid artery medial surface, anterior cerebral artery A1 and A2 proximal, middle cerebral artery M1 and M2 proximal.
Removing the anterior clinoid process
is an important step in exposing the structures in the cavernous sinus and is highly complicated due to the neuronal and vascular realtionships.
For example, the signal void caused by a pneumatized anterior clinoid process
may mimic an internal carotid artery aneurysm due to juxtaposition with the supraclinoid internal carotid artery.
Pneumatization may extend into the greater and lesser wings of the sphenoid or pterygoid process and the anterior clinoid process
; it can also extend into the occipital bone.
The CS anatomical knowledge is crucial also for the aneurysms arising from the ophthalmic segment of the carotid artery because the neck of the aneurysm is often hidden by the anterior clinoid process
. If these aneurysms have a superior or superomedial projection, the anterior clinoid process
must be drilled intradurally under direct visualization, because sometimes a broad neck of the aneurysms can penetrate the clinoidal space.
The anterior clinoid process
is a part of the roof to the cavernous sinus in its frontal portion.
Unlike the anterior clinoid process
, the posterior clinoid process has received less attention in past research studies.