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Metoptic canal, duplication of the optic canal and Warwick’s foramen in human orbits
No full textPurpose: The region of the optic strut can be traversed by some minor canals whose incidence and general characteristics have never been studied. As such canals could be the route for vessels that could interfere in the surgery of the orbital apex we undertook a detailed anatomical study on a vast collection of dry skulls.
Basic procedures: The examination of 943 dry adult skulls and 360 foetal skulls was carried out to precise the anatomy of canals in the optic strut area, their development and relationships with the optic canal.
Main findings: A canal traversing the optic strut was present in 8.54% of the orbits. Based on diameter, position within the optic strut, and thickness of the bony plate separating it from the optic canal or from the superior orbital fissure, the canals piercing the optic strut were classified in four types which include the well-known duplication of the optic canal, different aspects of the metoptic canal and a type of canal that to our knowledge has never been reported. Warwick’s foramen was found in 0.74% of orbits.
Principal conclusions: The area of the optic strut is the frequent site of canals joining the orbit with the middle cranial fossa. Some of them can host the ophthalmic artery, others could be run by minor vessels which, however, could be the source of annoying bleedings in surgical procedures
Metoptic canal and duplication of the optic canal in human orbits
Full text linkThe region of the optic strut can be traversed by some minor canals whose incidence and general characteristics have never been studied. As such canals could be the route for vessels that could interfere in the surgery of the orbital apex we undertook a detailed anatomical study on a vast collection of dry skulls. The examination of 943 dry adult skulls was carried out to precise the anatomy of canals in the optic strut area, their development and relationships with the optic canal. A canal traversing the optic strut was present in 8.54% of the orbits. Based on diameter, position within the optic strut and thickness of the bony plate separating it from the optic canal, the canals piercing the optic strut were classified in four types. Type I includes all cases of duplication of the optic canal (optic canal + ophthalmic canal) and it was observed in 0.64% of cases. Type I canal encompass cases of very large ophthalmic canals (diameter larger than 2 mm), far too large for the purpose of just transmitting the ophthalmic artery (type Ia), and cases of ophthalmic canals showing a calibre higher than 1 and lower than 2 mm and compatible, therefore, to host the ophthalmic artery (type Ib). Type II is a small channel that pierces the floor of the optic canal and runs backwards remaining separated from posterior part of the optic canal by a very thin (< 0.5 mm) bony plate that, for its thinness, could be the result of late events of calcification. The calibre of this kind of canal ranges from 120 μm to 1 mm and it was observed in 1.96% of cases. Type III is a small canal that traverses the whole thickness of the optic strut and a bony pillar or a thick bony lamina separate it from the optic canal. As the previous one, it can be very narrow or it can reach a respectable calibre though never larger than 1 mm, otherwise it would have been considered as type I canal. It was observed in 3.66% of cases. Type IV is a canal piercing the base of the optic strut. In 0.42% of orbits it traverses the entire thickness of the optic strut (type IVa) or in 2.07% of orbits it appears as a canal apposed to the lateral side of the optic strut (type IVb); as such, its very thin lateral wall is the only separation from the superior orbital fissure. In conclusion, the area of the optic strut is the frequent site of canals joining the orbit with the middle cranial fossa. Some of them can host the ophthalmic artery, others can be run by minor vessels which, however, can be the source of annoying bleedings in surgical procedures
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No full textShort replay to a letter referring to the article previously published and entitled "Hemodynamic and anatomic variations require an adaptable approach during intra-arterial chemotherapy for intraocular retinoblastoma: alternative routes, strategies and follow-up
Some observations over the article “Evaluation of the anastomoses between the ophthalmic artery and the middle meningeal artery by superselective angiography”
No full textDear Editor,
We read with interest the article entitled “Evaluation of the anastomoses between the ophthalmic artery and the middle meningeal artery by superselective angiography” [1]. The article supplies some original insights on the anatomy of the anastomoses, particularly as far as the caliber of the vessels is concerned.
However, we observed that it contains a series of angiographic misinterpretations and a methodologic flaw. The first misinterpretation refers to the artery identified in Fig. 4 as “recurrent meningeal branch”. The artery is actually a “marginal tentorial artery”, a vessel renamed by Lasjaunias et al. [4] as “superficial recurrent ophthalmic artery”. This is a small vessel that mostly originates from the internal carotid artery [3]. However, in 15% of cases it arises from intraorbital vessels (i.e. ophthalmic artery and lacrimal artery) and in 5% of cases from the middle meningeal artery (MMA) [4]. In addition to Lasjaunias’ angiographic demonstration of the artery [4], you can find a couple of recently published examples in Fig. 7B from Macchi et al. [5] and in Fig. 3.5 from Bertelli [2]. In the case of intraorbital origin, the marginal tentorial artery displays a recurrent course that crosses the superior orbital fissure. Indeed, the vessel shown in Fig. 4 is a meningeal artery and has a recurrent course. However, the name “recurrent meningeal branch” is usually reserved to a meningeal branch of the lacrimal artery (LA) which has been reported with a frequency ranging from 58 to 84% of cases depending on the statistical surveys [2]. We believe that this clarification is needed as the terminological confusion is a common and annoying companion of the vascular orbital anatomy. We would also like to point out a second possible misinterpretation in Fig. 4. By the examination of the figure, and without a selective angiography of the external carotid artery (ECA) demonstrating the proximal part of the MMA, it is impossible to affirm if the shown vascular pattern demonstrates a true anastomosis between the LA and the MMA (as the Authors choose to read it) or just an accessory MMA stemming directly from the LA. Figure 3 has been similarly misinterpreted. Again, without the selective angiography of the ECA, it is not possible to know if the proximal part of the MMA does exist. In addition, the supposed anastomosis does not seem to join the ophthalmic artery (OA) and the MMA. Rather, the supposed anastomotic vessel appears to bridge the LA (the LA is visible, though less evident than the anastomosis) and the MMA.
Because of the impossibility to ascertain if the vascular patterns are anastomoses with the MMA or just accessory MMAs arising from the orbital vessels, we believe that the article is methodologically flawed. To make a differential diagnosis between the two patterns, a selective ECA angiography is essential. Therefore, the angiographic visibility percentages of the anastomoses reported in the article are probably overestimated as they certainly also include an unspecified number of accessory MMAs arising from the orbit and wrongly interpreted as anastomotic vessels
Inter and intra-procedural hemodynamic variations in the orbit of children affected by intraocular retinoblastoma and treated with intraarterial chemotherapy
No full textA morphological study of the primary cilia in the rat pancreatic ductal system: ultrastructural features and variability
No full textPrimary cilia in the pancreas of the rat were studied by transmission electron microscopy. Their presence is very common, and each ductal cell seems to be provided with a single cilium. The basal body showed anchoring apparatus such as transitional fibers and basal feet. The shaft can show a number of different patterns according to the level of the sections. Proceeding towards the tip, the microtubules decrease in number, although not always in the same way. Near the tip, it is possible to detect patterns, with only 1 microtubule. Three kinds of tips are described. The function of the cilia is discusse
Cenni di anatomia del sistema articolare
No full textPrimo capito del libro "Malattie Reumatiche" che focalizza sull'anatomia delle articolazion
Branching of the foramen rotundum. A rare variation of the sphenoid
Full text linkThe human orbit communicates with the middle cranial fossa through several canals and openings. Some of them (optic canal, superior orbital fissure) are constant, others (meningo-orbital foramen, Warwick's foramen, metoptic canal) are less frequent. Here we report a rare variation of the foramen rotundum which, opening into the orbit with a branching canal, represented a further connecting pathway between the orbit and the middle cranial fossa. Such variation was detected in about 1.06% of individuals and it was almost always located on the right side. Only in one cases it could be found left-sided and in another skull it was spotted bilaterally. The vari- ation consisted of the branching of a 5 mm long canal from the lateral wall of the foramen rotun- dum that opened into the orbit. In general the diameter of the canal was comprised between 0.5 and 0.6 mm but it could be as large as 1 mm or as thin as 0.2 mm. The canal, straight and directed slightly superolaterally, likely transmitted the zygomatic nerve and/or part of the infraorbital nerve. To our knowledge, an independent entrance through a dedicated canal of such nerves has never been reported. The surgeons operating in this region, either neurosurgeons or ophthalmologists, should be aware of the possible variation in the course of these nerves
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