Transverse and oblique course of the vertebral artery over the medullospinal junction.

PURPOSE: The vertebral artery (VA) pierces the dura mater and continues with the intradural V4 segment. Once entered into the dura mater, the VA ascends from the infero-lateral to the antero-superior side of the medulla. Scarce reports of VAs compressing the medullospinal junction (MSJ) are available. We therefore aimed to determine the incidence of a course of the AV over the MSJ. METHOD: One hundred sixty-two archived CT angiogram files were documented in the study. We recorded the cases in which the VA crossed the MSJ. We assessed the VA as dominant, non-dominant or co-dominant. RESULTS: In 32 cases (19.75%), we identified intradural AVs on the ventral side of the MSJs. The incidence of this course of the VA was 17.1% in males and 23.81% in females. Of the 32 cases, the VA was non-dominant in 6, dominant in 14, and co-dominant in 12. CONCLUSION: The VA course over the MSJ is not rare. Therefore, when specific neurological signs of MSJ or medulla compression are found, the course of the VA should be documented on CT or MRI angiograms.

Gerstmann Syndrome in an Elderly Patient: A Case Report Presented with a Complete Tetrad of Symptoms.

Gerstmann syndrome, alternatively recognized as angular gyrus syndrome, epitomizes a complex cognitive impairment that has ignited substantial scholarly discourse within the realms of neurology and neuropsychology. The syndrome's original portrayal was, however, changed. It was demonstrated that the manifestation of its symptomatic tetrad, consisting of four main neurological impairments, is not invariably complete and frequently occurs alongside additional cognitive deficits. Furthermore, the precise cerebral localization of Gerstmann syndrome was traditionally posited to be the left angular gyrus; however, studies mention the possible involvement of other eloquent cerebral areas being pathognomonic. This case report delves into the case of an 86-year-old subject who exhibited the quintessential quartet of symptoms initially delineated by Josef Gerstmann, proposing that elderly patients may manifest a predisposition towards presenting the fully characterized symptomatology initially outlined by Gerstmann.

Coanda Effect Displayed in a Giant Intracranial Aneurysm.

The Coanda effect is a fluid dynamics phenomenon in which a fluid jet adheres to a convex or flat surface. This effect occurs when a liquid or gas jet emerging from an orifice clings to an adjacent surface and entrains the surrounding fluid, creating a lower-pressure region along its path that maintains its attachment to the surface. The Coanda effect accounts for the behavior of blood flow in the fetal right atrium and the dispersion of eccentric mitral regurgitation jets along atrial walls. This series of interesting images depicting a large 4 × 3.75 cm saccular intracranial aneurysm suggests that the Coanda effect may play a role in the pathophysiology of intracranial aneurysms and could be an underlying factor in their formation, progression, or rupture.

A Prevalence Anatomic-Imaging Study of the Posterior Inferior Cerebellar Artery's Origin.

Background and Objectives: Typically, the vertebral arteries (VAs) enter the posterior fossa through dural rings and further unite, forming the basilar artery. The posterior inferior cerebellar artery (PICA) is usually a branch of the V4 segment of the VA (intradural origin). It may also leave the V3 suboccipital segment of the VA (extradural origin). The transdural origin of the PICA within the VA's dural ring has been consistently overlooked. A study was designed to determine the topographical patterns of the PICA's origin. Materials and Methods: Determinations were performed in a retrospective sample of 225 computed tomography angiograms. Four types of PICA origin were documented: type 0, absent PICA; type 1, the extradural origin of the PICA from the V3 segment of the VA; type 2, the transdural origin of the PICA within the dural ring; and type 3, the intradural origin of the PICA from the V4 segment of the VA. The bilateral symmetry of types was also investigated. Results: Out of 450 VAs, type 0 (absent PICA) was found in 36%, type 1 (extradural) in 0.44%, type 2 (transdural) in 5.56%, and typical type 3 in just 58%. In types 1 and 2, the PICA entered the posterior fossa through the dural ring and the marginal sinus. In the overall group (N = 225), the type combinations 1_1, 1_2 and 1_3 were not found. Bilaterally absent PICAs occurred in 18.67%. The bilateral combinations 0_1/0_2/0_3/2_2/2_3/3_3 were found, respectively, in 0.89%/3.11%/30.67%/1.78%/4.44%/40.44%. Four of the seventy-eight PICAs opposite to an absent one, three intradural and one transdural, were true bihemispheric PICAs. Conclusions: The PICAs with extradural or transdural origins are facultative contents of the dural ring and are at risk during neurosurgical approaches in the foramen magnum. Rare bihemispheric PICAs could originate either intradurally or within the dural ring.

Anatomical Variations of the Jugular Bulb: A Critical and Comprehensive Review.

Background and Objectives: The jugular bulb (JB) is the uppermost part of the internal jugular vein receiving the sigmoid sinus. The aim of the present research is to aid the comprehension of the JB, its abnormalities, and surrounding structures for improving both academic and surgical awareness. Materials and Methods: Various studies on this topic were critically reviewed. Cone-beam CT scans and CT and MR angiograms were used to demonstrate each type of the discussed variations. Results: Variations in the JB anatomy were thoroughly documented: high JB, dehiscent JB, hypoplasia and hyperplasia, and diverticula of the JB, as they have significant clinical implications, particularly in the context of otological and neuro-otological surgery, skull base pathology, and diagnostic imaging. Definitions and critical arguments were also specified to clarify existing literature. Additionally, we present a case report illustrating a high and dehiscent JB, an anatomical variation of clinical interest due to its potential for misdiagnosis as a glomus tumor. Another case describes a dehiscent JB with a hypotympanic air cell protruding into it, further highlighting the variability of this condition. Conclusions: It is necessary to proceed with caution when observing abnormal morphological characteristics of the JB. Preoperative assessment of each case is essential for optimal outcomes.

An Update on the Superior Cerebellar Artery Origin Type.

Background and Objectives: The microanatomy of the superior cerebellar artery (SCA) is clinically significant. We, thus, aimed at patterning unilateral and bilateral possibilities of SCA origin. Materials and Methods: In total, 205 archived records of computed tomography and magnetic resonance angiograms were used. There were defined types of SCA origin from the basilar artery (BA): "0"-absent SCA, "1"-preterminal, "2"-collateral SCA, with SCA appearing as a terminal branch of BA, and "3"-SCA from the posterior cerebral artery (PCA) of the cerebral type. Fenestrations and duplications of SCA were recorded. Bilateral combinations of types were recorded as follows: A (1 + 0), B (1 + 1), C (1 + 2), D (1 + 3), E (1 + duplicated SCA), F (2 + 2), G (2 + 3), H (3 + 3), I (3 + duplicated SCA), J (1 + fenestrated SCA). Results: Type 0 SCAs were found in 0.25%, type 1 in 71.29%, type 2 in 19.06%, and type 3 in 9.41%. Absent and fenestrated SCAs were each found in a single case. The most frequent combinations were B (58.05%), C (13.17%) and F (13.17%). Bilateral symmetrical types occurred in 70.7% of cases. Fetal types of PCA and the artery of Percheron modified the BA ends. Combinations of C, F, and G changed the BA ends or tips; thus, different subtypes resulted in five BA bifurcation patterns, including five BA trifurcations and one BA quadrifurcation. BA trifurcation was also found in cases with duplicated SCAs. Conclusions: The SCA has various anatomical possibilities of origin and bilateral combinations that are not presented in anatomical lectures. Details on the specific end of the BA should be gathered on a case-by-case basis.

Transcallosal and Pericallosal Courses of the Anterior Cerebral Artery.

(1) Background: The anterior cerebral artery (ACA) has a precommunicating A1 segment, followed by a postcommunicating A2 segment. Anatomically, after it sends off from the callosomarginal artery (CMA), it continues as the pericallosal artery (PCalA). A detailed pattern of the anatomical variations of the PCalA are needed for practical reasons. (2) Methods: There were 45 retrospectively documented Computed Tomography Angiograms of 32 males and 13 females. (3) Results: In 90 sides, eleven different types of PCalA were documented: type 1: normal origin, above the genu of the corpus callosum (CC) (51.11%); type 2: low origin, below the rostrum of the CC (8.88%); type 3: late origin, above the body of the CC (3.33%); type 4, initial transcallosal course (3.33%); type 5, duplicated PCalA (1.11%); type 6, azygos PCalA (2.22%); type 7, absent PCalA (CMA type of ACA) (7.78%); type 8: CMA continued as PCalA (5.56%); type 9: PCalA continued as the cingular branch (1.11%); type 10: PCalA type of ACA, absent CMA (14.44%); type 11: triple PCalA, with an added median artery of the CC (1.11%). Different types of CMA were also documented: type 0, absent CMA (17.78%); type 1, CMA with frontoparietal distribution (45.56%); type 2, CMA with parietal distribution (22.22%); type 3, low origin of CMA, either from A1, or from A2 (8.88%); type 4, CMA continued as PCalA (5.56%). Ipsilateral combinations of PCalA and CMA types were classified as types A-P. In 33/45 cases (73.3%), the bilateral asymmetry of the combined anatomical patterns of PCalA and CMA was documented. Additional rare variations were found: (a) huge fenestration of A2; (b) bihemispheric ACAs (6/45 cases); (c) twisted arteries within the interhemispheric fissure. (4) Conclusions: The PCalA and CMA are anatomically diverse and unpredictable. Therefore, they should be documented on a case-by-case basis before surgical or endovascular approaches.

The transcerebral laterocavernous vein, a form of persisting primitive tentorial sinus.

The superficial middle cerebral vein (SMCV) commonly drains in the cavernous sinus. Its different drainage variants include preserved segments of the primitive tentorial sinus. In any of these variants, the terminal venous segment of SMCV passes on the base of the skull. The archived computed tomography angiograms of a 58-year-old female case were documented anatomically. On the left side was found the sinus of the lesser sphenoidal wing converging with the middle meningeal vein to form a venous channel located within the Sylvian fissure at 4 mm laterally to the cavernous sinus and trigeminal cavum. That venous channel was thus termed the 'laterocavernous vein'. It drained posteriorly within the superior petrosal sinus. This aberrant vein could interfere unpleasantly with pterional neurosurgical approaches for the Sylvian fissure, cavernous sinus or trigeminal ganglion.

A New Classification of the Anatomical Variations of Labbé's Inferior Anastomotic Vein.

(1) Background: The inferior anastomotic vein of Labbé (LV) courses on the temporal lobe, from the sylvian fissure towards the tentorium cerebelli and finishes at the transverse sinus (TS). The importance of the LV topography is related to skull base neurosurgical approaches. Based on the hypothesis of the existence of as yet unidentified anatomical possibilities of the LV, we aimed through this research to document the superficial venous topographic patterns at the lateral and inferior surfaces of the temporal lobe. (2) Methods: A retrospective cohort of 50 computed tomography angiograms (CTAs) of 32 males and 18 females was documented. (3) Results: Absent (type 0) LVs were found in 6% of cases. Anterior (temporal, squamosal-petrosal-mastoid, type 1) LVs were found in 12% of cases. LVs with a posterior, temporoparietal course (type 2) were found to be bilateral in 46% of cases and unilateral in 36% of cases. Type 3 LVs (posterior, parietooccipital) were found to be bilateral in 8% and unilateral in 32% of cases. In 24% of cases, duplicate LVs were found that were either complete or incomplete. A quadruplicate LV was found in a male case. On 78 sides, the LV drained either into a tentorial sinus or into the TS. (4) Conclusions: The anatomy of the vein of Labbé is variable in terms of its course, the number of veins and the modality of drainage; thus, it should determine personalized neurosurgical and interventional approaches. A new classification of the anatomical variations of Labbé's vein, as detected on the CTAs, is proposed here (types 0-3).

The Infraoptic or Infrachiasmatic Course of the Anterior Cerebral Artery Emerging an Elongated Internal Carotid Artery.

(1) Background: The normal A1 segment of the anterior cerebral artery (ACA) has a supraoptic course. The proximal infraoptic course of an A1 segment leaving the internal carotid artery (ICA) near the origin of the ophthalmic artery is a rare possibility. This study aimed to determine the prevalence and detailed anatomy of infraoptic A1 segments. (2) Methods: We retrospectively studied 145 computed tomography angiograms from 92 male and 53 female cases, with ages varying from 61 to 78 y.o. (3) Results: In 21/145 cases, infraoptic or infrachiasmatic horizontal-medial courses of A1 segments that emerged distally from the ICA were found. Distal infraoptic A1 segments were bilateral in 16/145 cases and unilateral in 3/145 cases. Infrachiasmatic A1 segments were found bilaterally in 2/145 male cases. All the infraoptic/infrachiasmatic A1 segments left long ICAs with low bifurcations. In 7/34 sides with distal infraoptic or infrachiasmatic A1 segments, supracarotid courses were present. In one female, the right A1 segment had an anterior supraclinoid, supracarotid and infraoptic course. In two female cases with a bilateral distal infraoptic A1, the segment was almost contacting the respective posterior cerebral artery. (4) Conclusions: In cases with dolicho(ectatic) ICAs, the A1 segments could have infraoptic and supracarotid courses the neurosurgeons should be aware of.

Patterns of Pneumatization of the Posterior Nasal Roof.

(1) Background: For good surgical performance, sound knowledge of anatomy is required. Although the ethmoid air cells and sphenoid sinuses are subject to a high degree of variation, their possible extensions above the nasal fossa at the posterior end of the cribriform plate of the ethmoid bone (CPEB) were seemingly overlooked. (2) Methods: We retrospectively studied 162 case files from 55 male and 107 female cases, with ages varying from 42 to 80, which were scanned using Cone Beam Computed Tomography. (3) Results: In 56.17% of cases, an unpneumatized CPEB (type I) was found. Nasal roof recesses of ethmoidal origin (type II) were found at the posterior end of the CPEB in 20.37% of cases. Different types of sphenoidal pneumatizations of the posterior end of the CPEB (type III) were found in 22.83% of the cases. Onodi cells projected nasal roof recesses (type IV) in only 10 cases. In all types, nasal roof recesses were found either above the CPEB or within/underneath it. Moreover, such nasal roof recesses were found to be either unilateral, extended contralaterally, or bilateral. (4) Conclusions: As such recesses of the posterior CPEB, previously overlooked, belong to the posterior rhinobase, they should be carefully documented preoperatively to avoid unwanted surgical damage to the olfactory bulb or CSF fistula.

Combined rare anatomic variants: persistent primitive olfactory artery and azygos pericallosal artery.

The persisting primitive olfactory artery (PPOA) is a rare anatomic variation of the anterior cerebral artery (ACA), being encountered in less than 1% of cases. Different morphological types were reported previously. In type 3, only once reported previously, the PPOA gives off two branches, a nasal one which courses in the olfactory sulcus to supply the territory of the anterior ethmoidal artery, and the callosomarginal artery. It is reported here a combination of rare anatomic variants found in a 71-year-old male patient investigated by computed tomography angiography. A left PPOA left the A1 segment of the ACA and was classified as subtype 3b, as its branches were the nasal one and a frontal trunk, not the callosomarginal artery. That PPOA had a characteristic hairpin turn applied on the anterior fossa floor. The ACA continued as azygos pericallosal artery, which is also a rare finding. As the nasal branch of the PPOA and its hairpin turn is closely related to the anterior fossa floor, such variant should be carefully documented when combined approaches of the skull base are planned by rhinologists and neurosurgeons.

Anatomic variations of the superficial temporal artery.

The superficial temporal artery (STA) is a terminal branch of the external carotid artery. It is commonly described as coursing posterior to the mandibular condyle and over the posterior zygomatic root (PZR) and then dividing terminally into parietal and frontal branches. However, possible variations of the main trunk of the STA have seemingly been overlooked. This study retrospectively examined the archived head tomography angiograms of 43 patients to determine the morphology and topography of the STA prior to its terminal bifurcation. In 79% of patients, the STA topography related to the mandibular condyle was bilaterally symmetrical, either retrocondylar (65.1%) or laterocondylar (13.6%). The parietal branch was sometimes absent unilaterally (16.3%) or bilaterally (9.3%). In 2/43 cases, the frontal branch of the STA was unilaterally absent. When both terminal branches were present, the bifurcation was retrocondylar or immediately above the PZR when on the PZR, or the terminal division of the STA was high above the PZR. In 88.4% of the STAs, different patterns of kinking and coiling were documented, including retrocondylar kinks (27.9%), laterocondylar kinks (20.9%), kinks placed on the PZR (81.4%) and variably oriented suprazygomatic kinks (32.6%). Five of the 86 STAs were coiled, one retrocondylar, one laterocondylar, and three other placed on the PZR. Two cases showed unilateral pseudoaneurysms of the STA, one above the PZR and the other on the temporomandibular joint. The STA is surgically important; therefore, the number of anatomical studies of the STA should increase.

Trifurcated external carotid artery and complete gamma-loop of its maxillary branch.

The external carotid artery (ECA) normally bifurcates terminally with the superficial temporal artery (STA) and the maxillary artery (MA). From the horizontally coursing, mandibular segment of the MA leaves the middle meningeal artery (MMA). We hereby report a previously unknown anatomic possibility, incidentally found during an angio-CT scan in an adult female patient. Unilaterally, the ECA was terminally trifurcated, sending off the MA, STA, and MMA. On that side, the mandibular segment of the MA had a gamma-loop and the contralateral one had a U-loop; both these loops were inferior to the lateral pterygoid muscle, closely approaching the respective lingula of the mandible. These findings are relevant during surgery of the parotid gland and infratemporal fossa, approaches of the MMA, and inferior alveolar nerve blocks. The modified origin of the MMA could be explained by an altered development of the primitive stapedial artery.