Concomitant completely ossified trigeminal pore and Dorello's canal.

Commonly, the trigeminal and abducens nerve course to the middle cranial fossa, beneath the tentorial border (posterior petroclinoid dural ligament) and, respectively, beneath Grüber's petrosphenoidal ligament, in Dorello's canal. It is hereby reported a rare unilateral association of anatomic variants which was found when the brain computed tomography angiography of a 56-year-old male patient was observed. On the left side, the tentorial border was ossified above the petrous apex, resulting in a tentorial bar 1.96 cm long that transformed the trigeminal pore into a completely ossified one. On that side was also found an ossified petrosphenoidal ligament determining a completely ossified Dorello's canal. On the opposite side a 2.9 mm long clinoid bar extended from the posterior clinoid process to the anterior one. Although these bars are not common in humans they should be documented in computed tomography in cases with associated trigeminal neuralgia and abducens nerve palsy.

The "sand watch" mandible.

The lingual surface of the mandible's body is commonly indicated as presenting the submandibular and sublingual fossae, which are separated by the mylohyoid line. The mylohyoid line attaches to the mylohyoid muscle (MM). Less attention has been paid to the 'mylohyoid boutonnières', which allow the 'sublingual buttons' to pass through the mylohyoid muscle in the submandibular space. The cone-beam computed tomography files of patients were routinely examined for anatomical studies. Two cases were found with unexpected morphologies of the mandible's body - the mylohyoid lines were incomplete anteriorly, and herniated sublingual tissue determined an additional fossa inferior to that line in the premolar region. That fossa was termed the 'accessory submandibular fossa'. It determined on coronal slices a 'sand watch' contour of the mandible's body. With such a peculiar morphology, the mandible is more prone to fracture. Moreover, when inserting endosseous implants, the procedure should be carefully personalised in such rare cases.

Evidence of lymphatics in the rat eye retina.

BACKGROUND: The lymphatic structure of the eye is still under debate. It is mainly assumed that the retina is primarily drained by prelymphatics and not by lymphatics per se. We aimed to identify lymphatics in the rat retina. METHODS: Eyes from ten Wistar rats were paraffin-embedded and the lymphatic marker podoplanin (D2-40) was investigated. RESULTS: We identified in the rat retina a blunt-end network of lymphatic endothelial vessels. It consisted of circumferential vessels within the outer and, respectively, inner plexiform layers, connected by radial dichotomous vessels. Moreover, D2-40 expression was found within the choroid, ciliary body, and extraocular muscles. CONCLUSIONS: This in situ evidence is strongly supported by the recent in vitro demonstration of the expression of lymphatic markers in retinal endothelial cells. Further studies of comparative histology should use specific lymphatic markers to test whether other species besides rats have proper retinal lymphatics.

Transantral intraseptal sinuous canal.

The sinuous canal is an anatomically well-defined intramural canal of the maxillary sinus (MS) folded within the antral walls. Commonly, its first, infraorbital part, courses within the antral roof, while its second, transverse facial part courses below the infraorbital foramen within the anterior antral wall. While retrospective files of patients that were scanned in cone-beam computed tomography (CBCT) for different dental medical purposes were observed randomly, a peculiar variant of the sinuous canal was noticed and further documented. The respective canal origin was far posterior in the infraorbital groove and the canal coursed through the MS embedded within an incomplete oblique septum dividing the antrum into anterosuperior and posteroinferior chambers. Then the sinuous canal continued with the transverse facial segment. As the sinuous canal contains the superior anterior alveolar nerve and artery, major suppliers of the frontal teeth, it is recommended to document in CBCT a possible transantral, and not intramural, course of it, especially when surgical or endoscopic corridors through the MS are planned.

An arc of Bühler variant.

The celiaco-mesenteric anastomoses occur either directly between the celiac trunk and the superior mesenteric artery (SMA), or between different branches of them. A rarely occurring such anastomosis is the arc of Bühler. A new variant of arc of Bühler was found incidentally during a retrospective study of the computed tomography angiograms of a 62 y.o. male patient. In that case, the arc of Bühler left from the splenic artery and inserted into the inferior pancreaticoduodenal artery (IPDA), proximally to the IPDA division into its anterior and posterior branches. Moreover, that arc of Bühler was giving off a mesenterico-jejunal branch, which descended applied on the anterior side of the SMA. Such anatomic variants could impede on the surgical or interventional procedures in the duodenopancreatic region, or could be physiologically useful to divert the celiac flow towards the mesenteric territory, or vice versa.

Two cases of combined anatomical variations: maxillofacial trunk, vertebral, posterior communicating and anterior cerebral atresia, linguofacial and labiomental trunks.

BACKGROUND: Commonly, arterial anatomic variants are reported as single entities. However, different such variants can occur in a single patient. MATERIALS AND METHODS: During a retrospective study of computed tomography angiograms of 52 adult patients, 2 cases were found with unilateral maxillofacial trunks. In each case different other anatomic variants were documented. RESULTS: The maxillofacial trunk in the first case was associated with bilateral posterior kinks of the internal carotid artery which passed beyond the transverse processes of the atlas vertebra and indented and displaced the internal jugular veins. Common carotid origins of the superior thyroid arteries were found, as well as a high origin of the contralateral facial artery. In the second case a plethora of variants were associated with a unilateral maxillofacial trunk: 1) direct occipital-vertebral arterial anastomosis; 2) ipsilateral atresia of the distal vertebral artery and of the A1 segment of the anterior cerebral artery; 3) bilateral atresia of posterior communicating arteries; 4) linguofacial and labiomental trunks; 5) terminal trifurcation of the external carotid artery. CONCLUSIONS: The arterial anatomical variants of the head and neck should be carefully documented prior to specific surgical and interventional procedures, as well as for understanding the compensatory anatomical pathways of circulatory insufficiencies.

Bilateral absence of the transverse sinuses with fenestrated superior sagittal sinus draining through enlarged occipital and marginal sinuses.

The endothelial-lined dural venous sinuses collect blood from the brain, meninges, and calvaria and drain it to the internal jugular veins. The adult drainage pathway of the venous sinuses confluent is commonly via the transverse and sigmoid sinuses to the jugular bulb. The occipital (OS) and marginal (MS) sinuses are well-represented before birth, in most cases. During a retrospective study of the computed tomography angiograms of a 64-year-old female was found a rare combination of variants of the posterior fossa sinuses. The confluence of the dural venous sinuses was rhomboidal and drained superiorly the superior sagittal sinus, and inferiorly a well-represented OS. The transverse sinuses were aplastic, on the right side, and hypoplastic on the opposite side. The OS further drained into the MS which, on each side, emptied into the respective jugular bulb. On each side a condylar vein left the junction of the sigmoid sinus and jugular bulb. Such posterior fossa drainage, exclusively on the OS-MS pathway, should be kept in mind when transections of the venous sinuses are intended during neurosurgical approaches of the foramen magnum. The OS-MS drainage is rather a persisting foetal pattern. The bilateral anatomical exclusion of the transverse sinuses is an added condition to spare the OS and MS.

Hexafurcated coeliac trunks, trifurcated common hepatic artery, and a new variant of the arc of Bühler.

BACKGROUND: The coeliac trunk (CT) is well-known as trifurcated into the left gastric (LGA), common hepatic (CHA) and splenic (SA) arteries. MATERIALS AND METHODS: Scarce reports indicate that the CT could appear quadri-, penta-, hexa-, or even heptafurcated. Reports of CTs with six branches (hexafurcated CT) are few, less than ten. The hexafurcated CT variant was documented by a retrospective study of 93 computed tomography angiograms. RESULTS: Two hexafurcated CTs were found. In one case an arc of Bühler was added to the inferior phrenic arteries, LGA, CHA and SA. In the second case the dorsal pancreatic artery was added to the other five branches. That arc of Bühler descended in front of the aorta to connect with the origin of the third jejunal artery. The CHA in that second case was trifurcated into the left and right hepatic arteries, and the gastroduodenal artery; the proper hepatic artery was absent. CONCLUSIONS: Although the hexafurcated CT, as well as the trifurcated CHA, are rarely occurring and reported anatomic variants, this doesn't mean they could not be encountered during surgical or interventional procedures, which they would complicate if not recognised. Moreover, the arc of Bühler, the embryonic remnant, was not reported previously to insert into the CT as an additional branch of it.

Nestin and dental pulp stones - a case report-driven hypothesis.

The dental pulp stem cells (DPSCs) are mesenchymal stem/stromal cells (MSCs) with multilineage potential of differentiation. Different studies investigated dental pulp stones (PS), the calcified masses in the dental pulp, in regard to their prevalence, topography and structure. The etiology of PS is still unclear and, to our knowledge, the DPSCs were not attributed yet specific roles in PS formation. We report here an immunohistochemical study of a PS-embedding dental pulp from an impacted third mandibular molar of an adult patient, in which we used antibodies against CD34, Ki67, glial fibrillary acidic protein (GFAP), α-smooth muscle actin (α-SMA) and nestin. While endothelial cells expressed CD34 and pericytes or vascular smooth muscle cells expressed α-SMA, DPSCs and the osteoblasts coating the PS were exclusively labeled with nestin antibody. Stromal networks of nestin-expressing DPSCs were regarded as in situ providers of osteogenic progenitors involved in PS formation. Further experimental studies, with larger lots of tissue samples, as well as extended panels of markers, are needed in order to elucidate the DPSC hypothesis in the PS etiology.

A glimpse of past, the temporo-buccinator band of Hovelaque, or the buccotemporal fascia of Zenker.

Only a few studies published until now have described the fascial-tendinous complex between the temporal and the buccinator muscles, which will be reviewed here. In 1957, the "temporo-buccinator band" (TBB) was described by Gaughran, who gave credit to Hovelaque for its first description in 1914. Zenker coined it in 1955 as the "buccotemporal fascia" (BTF). A buccal extension of the temporal muscle tendon extends from the temporal crest of the mandible to insert within the buccinator muscle, anterior to the pterygomandibular raphe, and posterior to the parotid duct that perforates the buccinator. That tendinous expansion is embedded within the buccotemporal fascia, which is oriented antero-infero-medially and joins the buccopharyngeal fascia, forming the TBB/BTF, above which we find the buccal fat pad. The buccal nerve and artery cross this anatomical structure. The TBB/BTF is an additional layer closing the pterygomandibular space anteriorly, and its knowledge is needed for practitioners performing inferior alveolar nerve blocks.

The sphenozygomatic fissure.

The lateral (temporal) wall of the orbit separates it from the temporal fossa and the anterior part of the temporal muscle. Within this wall, the sphenozygomatic suture joins the greater wing of the sphenoid bone and the zygomatic bone. We retrospectively documented in cone-beam computed tomography the anatomy of the orbit in a 56-year-old female and we found a previously unreported anatomic variant. The greater wing of the sphenoid bone and the zygomatic bone were separated, bilaterally, by a large unossified space which we termed the sphenozygomatic fissure. This was merged inferiorly with the inferior orbital fissure. A possible imbalanced mechanism of membranous ossification of both the zygomatic bone and the orbital surface of the greater wing could be speculated as a possible cause for such sphenozygomatic fissure. This previously undocumented anatomic variant is of high clinical relevance, since it may allow orbital fat to herniate (or bulge) toward the temporal fossa, it may be easily damaged during minor trauma and it should be carefully approached during the surgery of the orbit through the lateral wall.

Hepatomesenteric trunk, gastrosplenic trunk, coiled splenic and hepatic arteries, and a variant of Bühler's arc.

The coeliac trunk is normally divided into the left gastric artery (LGA), splenic artery, and common hepatic artery (CHA). The combination between these arteries and the superior mesenteric artery (SMA) generates various combinations. We report here such a rare anatomic variant, namely the hepatomesenteric trunk (HMT), combined with a gastrosplenic trunk (GST). The variant was identified using computed tomography angiograms of a 62-year-old woman. The GST emerged from the aorta within the aortic hiatus of the diaphragm, a previously unknown possibility. Further, an accessory left hepatic artery originated from the LGA. The phrenic arteries had independent aortic origins. The HMT divided into the CHA and the SMA posterior to the origin of the hepatic portal vein (PV), above the pancreas. The CHA initially had a right course, towards the superior border of the PV, then it descended with a transpancreatic course posterior to the PV, reached its inferior/right border, and divided antero-inferiorly to the PV into the proper hepatic and gastroduodenal arteries. The proper hepatic artery continued on the anterior side of the PV, sending off the left and right hepatic arteries. The HMT and the GST were connected by a rudimentary variant of the arc of Bühler, unreported previously. Arterial variations in the coeliac region are accurately distinguished on computed tomography angiograms. They should be evaluated by surgeons when different surgical procedures are evaluated.

The mandibular incisive foramen, a false mental foramen.

BACKGROUND: The mandibular incisive foramen (MIF) is an opening on the external surface of the dentate mandibular body, medial to, and facing the mental foramen (MF). There is actually scarce evidence of such MIF. CLINICAL PRESENTATION: A retrospective Cone Beam CT (CBCT) study of the archived files of a 56 y.o. male patient was documented anatomically for dental medical purposes. In the 2nd premolar region of the left hemimandible were found two adjacent foramina facing one each other: the distal one was opened medially, while the medial one was oriented distally. On axial CBCT slices the mandibular canal was detected to open at the distal foramen in the outer cortical plate of the mandible. The medial foramen in that cortical plate served as entrance to the mandibular incisive canal, thus being a MIF. CONCLUSION: CBCT accurately distinguishes the canals opening on the outer cortical plate of the mandible thus is of use to differentiate a MIF from a MF. Such adjacent foramina expose at risk not just the mental nerve, as in cases with true multiple MF, but also the IAN and the mandibular incisive nerve.

The sagittal grooves of the middle nasal turbinate determine paradoxical curvatures and bifidities.

BACKGROUND: Paradoxical curvature of the middle nasal turbinate (MT) is a common anatomic variant, usually found and reported on coronal CT slices. However, less attention has been paid to the sagittal groove (SG) which is determining it. AIM: The study aimed to determine paradoxical curvatures and bifidities in the sagittal groves of middle nasal turbinate. MATERIAL AND METHOD: A retrospective CBCT study on the archived files of 52 adult patients was performed. RESULTS: Different patterns of MT bifidity were found: (1) unilateral bifid MTs; (2) bifid and trifid MTs and "wandering" single SGs; (3) bilateral bifid middle turbinates and double SGs, (4) bilateral false bifid appearance due to middle and superior turbinates fusion and (5) bifid concha bullosa media. Digital "dissections" of patients' files allowed us to conclude that paradoxical curvature as well as bifidity of MTs relate to the placement and number of the SGs on the MTs. Such SGs were previously documented in prenatal MTs since the 14th week, as well as in pædiatric patients. CONCLUSIONS: It seems reasonable to speculate that paradoxical curvature, as well as bifidity of MT, this later being previously undocumented, are just adult vestiges of the primitive MT morphology. Nevertheless, documentation of the MT morphology should not rely exclusively on coronal CTs, as combined morphologies of that turbinate could occur.

The unusually lower position of the mandibular foramen and the canal of the neck of mandible.

BACKGROUND: The inferior alveolar nerve (IAN) courses through the mandibular foramen (MF) to enter the first segment of the mandibular canal (MC) in the mandibular ramus, to further supply with trigeminal fibers the lower teeth of that hemimandible. As the IAN also supplies the mylohyoid nerve, it is a mixed nerve. METHODS: Unusual morphologies of the mandibular ramus were encountered during a retrospective study of archived CBCT files. RESULTS: A previously unreported anatomic variation was found bilaterally in an edentulous mandible, consisting of a lowered position of the MF, with seemingly compensatory lengthening and enlargement of the sulcus colli, thus shortened MCs. Also, a rare neurovascular canal of the neck of the mandible was incidentally found unilaterally in another case and is reported here. CONCLUSIONS: Such possibilities of variation could justify the individual effect of the IAN block.

Three-dimensional anatomy of the transantral intraseptal infraorbital canal with the use of cone-beam computed tomography.

The transantral or ectopic infraorbital canal (IOC) courses diagonally through the maxillary sinus (MS), thereby being exposed to risk during a number of surgical procedures. A few prior reports have presented evidence of a septa-embedded IOC, albeit only on single-plane slices. We identified this extremely rare variation of the IOC during a retrospective study of the cone-beam computed tomography files of 2 patients. In the first case, which involved a 34-year-old female patient, the canals and septa within the MS were bilaterally asymmetrical. On the right side, the sinus roof was attached to a short transverse septum that was traversed by the IOC, while the left sinus featured an oblique large septum that divided it into antero-superior and posterior chambers. The left IOC was embedded within the septum rather than within the orbital floor above the septum. In the second case, which concerned a 36-year-old male patient, the left MS featured an almost completely oblique/vertical septum that divided it into anterior and posterior chambers and also embedded the respective IOC, which was thus absent from the orbital floor. In both cases, infraorbital recesses in the anterior chambers of the MS were found that, if not documented on three-dimensional (3D) renderisations, could have been misidentified as infraorbital (Haller) cells. To the best of our knowledge, this is the first report to document the 3D anatomy of an extremely rare variant, namely a septum-embedded transantral IOC. Such a variant, if not adequately documented preoperatively, could divert the transmaxillary corridors down false paths or else expose the IOC to damage during surgical procedures involving access to tumours.

Air spaces neighbouring the infraorbital canal.

OBJECTIVE: The infraorbital canal (IOC) courses through the roof of the maxillary sinus (MS). Different grading systems concerning the topography of the IOC have been proposed. Further, it has been suggested that a transantral IOC would be morphologically related to Haller's cells (HCs). However, we hypothesized that this is not necessarily the case. Hence, we aimed to study the anatomical possibilities of the air spaces located medially to the IOC. MATERIALS AND METHODS: The cone-beam computed tomography (CBCT) files of 40 adult patients were retrospectively evaluated. RESULTS: The transantral type of IOC was found in 32.5% of patients. The infraorbital recesses of the MS were found medial to the IOC in 20% of patients. As referred to the nasolacrimal canal, these recesses were either prelacrimal (appearing as false isolated air cells) or retrolacrimal (appearing as false HCs). True HCs were found in 10% of patients. They were located medial to the IOC and they drained into the ethmoidal infundibulum (EI), which was distinct from the MS drainage. In 15% of patients, aerated nasolacrimal ducts (NLDs) were found anterior to the EI and medial to the antral angle. They were capable of masquerading either a HC or an infraorbital recess of the MS. CONCLUSION: Previous classifications of the IOC, which related it to HCs, were reviewed and the evidence was found to be insufficient to assess the HC-related topography of the IOC. Therefore, to achieve the accurate anatomical identification of the air spaces neighbouring the IOC, the infraorbital recesses of the MS, the HCs, and the aerated NLDs should be carefully discriminated within the antero-supero-medial antral angle.

The ultrastructural anatomy of the nuclear envelope in the masseter muscle indicates its role in the metabolism of the intracellular Ca+.

Specific ultrastructural anatomy of masticatory muscles is commonly referred to a general pattern assigned to striated muscles. Junctional feet consisting of calcium channels of the sarcoplasmic reticulum (i.e. the ryanodine receptors, RyRs) physically connected to the calcium channels of the t-tubules build triads within striated muscles. Functional RyRs were demonstrated in the nuclear envelopes of pancreas and of a skeletal muscle derived cell line, but not in muscle in situ. It was hypothesized that ryanodine receptors (RyRs) could also exist in the nuclear envelope in the masseter muscle, thus aiming at studying this by transmission electron microscopy. There were identified paired and consistent subsarcolemmal clusters of mitochondria, appearing as outpockets of the muscle fibers, usually flanking an endomysial microvessel. It was observed on grazing longitudinal cuts that the I-band-limited mitochondria were not strictly located in a single intermyofibrillar space but continued transversally over the I-band to the next intermyofibrillar space. It appeared that the I-band-limited transverse mitochondria participate with the column-forming mitochondria in building a rather incomplete mitochondrial reticulum of the masseter muscle. Subsarcolemmal nuclei presented nuclear envelope-associated RyRs. Moreover, t-tubules were contacting the nuclear envelope and they were seemingly filled from the perinuclear space. This could suggest that nucleoplasmic calcium could contribute to balance the cytosolic concentration via pre-built anatomical routes: (i) indirectly, via the RyRs of the nuclear envelope and (ii) directly via the communication of t-tubules and sarcoplasmic reticulum through the perinuclear space.

A rare anatomic variation: Triple mental foramina.

Multiple mental foramina (MF) are rarely found in the human mandible. We report on the case, as documented using cone beam computed tomography (CBCT), of the triple MF that were identified on the right hemimandible of a 28-year-old female patient. The distal foramen was located on the mandible between the apices of the second premolar root and the first molar mesiovestibular root, being reached by a thin canal that left the mandibular canal. A pair of mesial foramina were identified between the apices of the premolar teeth. Thus, the three foramina corresponded to a surface area of 23.49mm2 of the mandible. On the opposite side, a single mental foramen had a surface area of just 13.25mm2. On each side, retromolar canals that opened into the retromolar fossae were also found. The anatomic possibility of multiple MF increases the surface area at risk during surgical procedures, increases the risk of neurovascular damage and obscures the common tooth-related location of the mental foramen. Practitioners should, therefore, consider a personalised and imaging-documented approach so as to avoid treatment failure.

Bilateral giant and unilateral duplicated sphenoidal tubercle.

The sphenoidal tubercle (SphT), also known as pyramidal tubercle or infratemporal spine projects from the anterior end of the infratemporal crest of the greater sphenoidal wing. As it masquerades the lateral entrance in the pterygopalatine fossa it could obstruct surgical corridors or the access for anaesthetic punctures. The SphT is, however, an overlooked structure in the anatomical literature. During a routine cone beam computed tomography study in an adult male patient we found bilateral giant SphTs transforming the infratemporal surfaces of the greater wing into veritable pterygoid foveae. Moreover, on one side the SphT appeared bifid, with a main giant partition, of 9.17 mm vertical length, and a secondary laminar one. The opposite SphT had 14.80 mm. In our knowledge, such giant and bifid SphTs were not reported previously and are major obstacles if surgical access towards the pterygopalatine fossa and the skull base is intended.