optic canal


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optic canal

[′äp·tik kə′nal]
(anatomy)
The channel at the apex of the orbit, the anterior termination of the optic groove, just beneath the lesser wing of the sphenoid bone; it gives passage to the optic nerve and ophthalmic artery.
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The average distances from the frontozygomatic suture, superior aspect of the superior orbital fissure, Whitnall's tubercle, superior aspect of the optic canal, and superior aspect of the supraorbital notch to the metoptic canal were 29.51 [+ or -] 11.20, 15.80 [+ or -] 4.26, 22.85 [+ or -] 9.95, 8.90 [+ or -] 2.74, and 40.62 [+ or -] 8.87 mm in the right side, respectively.
Optic strut is a piece of bone located between upper side of body and lesser wing of sphenoid, which separates optic canal from medial side of superior orbital fissure.(7) Length of optic strut was measured from the side of body of sphenoid to the ACP (Fig.
In diagnostic procedures, CThis the neuroimaging study of choice for visualizing the bones of the optic canal, the paranasal and frontal sinuses.
They were referred to a neurosurgeon (H.A.M.) for evaluation and interpretation of high-resolution orbital and optic canal computed tomography (CT) scans performed at presentation.
According to the imaging findings, patients with no obvious changes in the optic canal and SOF can receive mainly mega dose corticosteroid treatment.
The intracranial extension has been described through the three major openings in the posterior aspect of the orbit, which include the superior orbital fissure, optic canal and the inferior orbital fissure.
IOF: Infraorbital foramen; ZMS: Zygomatico- maxillary suture; OC: Optic canal; IF: Inferior orbital fissure; SF: Superior orbital fissure; ANS: Anterior nasal septum.
Orbital Computed Tomography (CT) (Figure 1, A) demonstrated inflammatory opacification of the left sphenoid sinus and unusual bony dehiscence at the proximal optic canal. Magnetic Resonance Imaging (MR) (Figure 1, B) revealed mild left proptosis with diffuse inflammatory enhancement of the intraconal fat and optic nerve sheath spanning mid orbit to apex.
It extended inferiorly to the right infratemporal fossa, posteriorly to the petrous bone close to the right carotid canal, inferomedially to the right parapharyngeal space, medially to the right lateral nasal wall, anterosuperiorly to the right orbit through the inferior orbital fissure, superoanteriorly compressing the right optic canal and superoposteriorly to the sphenoid bone.
Occulomotor (3rd), supratrochlear (4th), first branch of trigeminal (5th) and abducent (6th) cranial nerves enter the orbit through the supraorbital fissure while the optic nerve along with the ophthalmic artery enters the orbit via the optic canal. Any inflammation involving the orbital apex will interrupt the nerves in these bony canals leading to ophthalmoplegia, loss of vision and ocular sensations (orbital apex syndrome).
During the current admission, computed tomography (CT) of the head was performed, showing a focal inflammatory process on the left side of the sphenoid sinus with an unusual dehiscence of the medial portion of the proximal optic canal (figure, A).
The anterior part of the superior wall is delimited by the optic nerve confined within the optic canal, the medial aspect of the third cranial, and the dura extending between the dural entry point of the third cranial nerve and the optic nerve.