The temporomandibular joint: pneumatic temporal cells open into the articular and extradural spaces

The pneumatisation of the articular tubercle (PAT) of the temporal squama is a rare condition that modifies the barrier between the temporomandibular joint (TMJ) space and the middle cranial fossa. During a routine examination of the cone-beam computed tomography (CBCT) files of patients who were scanned for dental medical purposes, we identified a case with multiple rare anatomic variations. First, the petrous apex was bilaterally pneumatised. Moreover, bilateral and multilocular PAT were observed, while on one side it was further found that the pneumatic cells were equally dehiscent towards the extradural space and the superior joint space. To the best of our knowledge, such dehiscence has not previously been reported. The two temporomastoid pneumatisations were extended with occipital pneumatisations of the lateral masses and occipital condyles, the latter being an extremely rare evidence. The internal dehiscence of the mandibular canal in the right ramus of the mandible was also noted. Additionally, double mental foramen and impacted third molars were found on the left side. Such multilocular PAT represents a low-resistance pathway for the bidirectional spread of fluids through the roof of the TMJ. Further, it could add to a morphological picture of hyperpneumatisation of the posterior cranial fossa floor, which could signify the involvement of the last four cranial nerves in the clinical picture of TMJ pain. 

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

Transantral intraseptal sinuous canal

The sinuos 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

The Diversity of the Linguofacial Trunk

Background and Objectives: Typically, the external carotid artery (ECA) sends off separate anterior branches: the superior thyroid, lingual, and facial arteries. These could, however, form common trunks: thyrolinguofacial, linguofacial (LFT), or thyrolingual. Although known, the LFT variant was poorly detailed previously, and most authors just counted the variant. We aimed to demonstrate the individual anatomical possibilities of the LFT on a case-by-case basis. Materials and Methods: 150 archived angioCT files were used. After applying inclusion and exclusion criteria, 147 files of 86 males and 61 females were kept for this study. Results: In 34/147 cases, LFTs were found (23.12%). Bilateral LFTs were found in 13/34 cases (38.24%) and unilateral LFTs in 21/34 (61.76%) cases. Forty-seven LFTs were thus identified and further studied for different variables. Regarding the vertical topography of LFT origin, type 1a (suprahyoid and infragonial) was found in 28 LFTs (59.57%), type 1b (suprahyoid and gonial) was found in eight LFTs (17.02%), type 3 (suprahyoid and supragonial) was found in two LFTs (4.25%), type 2 (hyoid level of origin) in eight LFTs (17.02%), and type 3 (infrahyoid origin) in just one LFT (2.12%). Types of the initial course of the LFT were determined: type I, ascending, was found in 22/47 LFTs; type II, descending, in 12/47 LFTs; and type III, transverse, in 13/47 LFTs. Regarding the orientation of the first loop of the LFT, 23/47 LFTs had no loop, 4/47 had anterior loops, 1/47 had a posterior loop, 5/47 had superior loops, 5/47 had inferior loops, and 9/47 had medial loops. The position of the LFT relative to the ECA was classified as medial, anterior, or antero-medial. An amount of 12/47 LFTs were anterior to the ECA, 22/47 were antero-medial, 10/47 were medial, 2/47 were inferior, and 1/47 was lateral. Regarding their general morphology, 23/47 LFTs had a rectilinear course, 22/47 had loops, and 2/47 were coiled. A case-by-case presentation of results further demonstrated the diversity of the LFT. Conclusions: In conclusion, the morphology and topography of the LFT are individually specific and unpredictable. It can be anticipated case-by-case by surgeons on CT or MR angiograms

Vertical Levels of the Occipital Artery Origin

Background and Objectives. The occipital artery (OA) is a posterior branch of the external carotid artery (ECA). The origin of the OA is commonly referred to a single landmark. We hypothesized that the origin of the OA could be variable as referred to the hyoid bone and the gonial angle. We thus aimed at patterning the vertical topographic possibilities of the OA origin. Materials and Methods. One hundred archived computed tomography angiograms were randomly selected, inclusion and exclusion criteria were applied, and 90 files were kept (53 males, 37 females). The cases were documented bilaterally for different levels of origin of the OA origin: type 1—infrahyoid; type 2—hyoid; 3—infragonial; 4—gonial; 5—supragonial; 6—origin from the internal carotid artery (ICA). Results. The incidence of unilateral types in the 180 OAs was: type 1—1.11%, type 2—5.56%, type 3—40.56%, type 4—28.33%, type 5—23.33% and type 6, ICA origin of the OA—1.11%. There was found a significant association between the location of the left and right origins of the OAs (Pearson Chi2 = 59.18, p Conclusions. The ICA origin of the OA is an extremely rare variant. For surgical planning or prior to endovascular approaches the topography of the OA origin should be carefully documented, as it may be located from an infrahyoid to a supragonial level

The Basal or Sphenopetrosal Superficial Middle Cerebral Vein Type

Background and Objectives: The adult superficial middle cerebral vein (SMCV) commonly drains into the middle cranial fossa. However, different embryonic types persist, in which the SMCV drains into the lateral sinus. The basal type of SMCV coursing on the middle fossa floor is a scarce variant. Materials and Methods: During a retrospective study of archived computed tomography angiography (CTA) and magnetic resonance angiography (MRA) files, three rare adult cases of the basal or sphenopetrosal type of SMCV were found and further documented. Results: In the first case, which was evaluated via CTA, the basal type of SMCV formed a sagittal loop. It continued on the middle fossa floor, over a dehiscent tegmen tympani, to drain into the lateral sinus. In the second case, documented via MRA, the basal type of SMCV’s anterior loop was in the coronal plane and closely related to the internal carotid artery and the cavernous sinus. It continued with the basal segment over a dehiscent glenoid fossa of the temporomandibular joint (TMJ). In the third case, documented via CTA, the initial cerebral part of the SMCV had a large fenestration. The middle fossa floor coursed within a well-configured sulcus of the SMCV and received a tributary through the tympanic roof. Its terminal had a tentorial course. Conclusions: Beyond the fact that such rare variants of the SMCV can unexpectedly interfere with specific approaches via the middle fossa, dehiscences of the middle fossa floor beneath such variants can determine otic or TMJ symptoms. Possible loops and fenestrations of the SMCV should be considered and documented preoperatively

Concomitant completeley 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 y.o. male patient was observed. On the left side the tentorial border was ossified above the petrous apex, resulting a tentorial bar long of 1.96 cm 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 for humans they should be documented in computed tomography in cases with associated trigeminal neuralgia and abducens nerve palsy

Vertical Levels of the Occipital Artery Origin

Background and Objectives. The occipital artery (OA) is a posterior branch of the external carotid artery (ECA). The origin of the OA is commonly referred to a single landmark. We hypothesized that the origin of the OA could be variable as referred to the hyoid bone and the gonial angle. We thus aimed at patterning the vertical topographic possibilities of the OA origin. Materials and Methods. One hundred archived computed tomography angiograms were randomly selected, inclusion and exclusion criteria were applied, and 90 files were kept (53 males, 37 females). The cases were documented bilaterally for different levels of origin of the OA origin: type 1—infrahyoid; type 2—hyoid; 3—infragonial; 4—gonial; 5—supragonial; 6—origin from the internal carotid artery (ICA). Results. The incidence of unilateral types in the 180 OAs was: type 1—1.11%, type 2—5.56%, type 3—40.56%, type 4—28.33%, type 5—23.33% and type 6, ICA origin of the OA—1.11%. There was found a significant association between the location of the left and right origins of the OAs (Pearson Chi2 = 59.18, p < 0.001), which suggests the presence of a strong symmetry of the origins. Bilateral symmetry of the vertical types of the OA origin was observed in 56.67% of cases; in 43.33% there was bilateral asymmetry. Conclusions. The ICA origin of the OA is an extremely rare variant. For surgical planning or prior to endovascular approaches the topography of the OA origin should be carefully documented, as it may be located from an infrahyoid to a supragonial level