A rare anatomical variation in foramen of Vesalius: A useful guide for maxillofacial surgeons

Background: Foramen of vesalius is an inconstant foramen that gives passage to an emissary vein that connects pterygoid venous plexus with cavernous sinus. It lies in the anteromedial side of the foramen ovale. Foramen ovale allows the passage for the mandibular branch of trigeminal nerve, the main site for the trigeminal rhizotomy. The presence and description of anatomical variations about the foramen of Vesalius is important during the surgical procedure on the trigeminal nerve which may injure the emissary vein in the foramen leading to intracranial bleeding. Objectives: The aim of the present study is to report the presence and to enlighten the anatomical variations of foramen vesalius which may serve as a guideline for surgeons. Methods: The study was conducted on 100 dry adult human skulls collected from the department of anatomy at Panimalar medical college hospital & research institute Chennai. The skulls were viewed both extracranially and intracranially to identify the presence of foramen of vesalius. The presence and variation of the foramen was noted and discussed. Result: A total of about 200 sides of 100 skulls were studied. Among them 20% of the skull showed presence of foramen of Vesalius bilaterally, 25% unilaterally and one particular skull showed doubled opening on the left side with the presence of a bony septum. This is a rare variation which was less documented in the literature. Conclusion: The knowledge of variations in foramen of Vesalius may help the surgeons for safer planning and execution of the trigeminal rhizotomy technique.

The eagle jugular syndrome as the cause of delayed intracranial hemorrhage after microvascular decompression for hemifacial spasm: A case report

Background: Eagle syndrome is a rare disorder whereby an elongated styloid process (ESP) causes not only some otolaryngological symptoms, but also cerebrovascular events caused by compression of the carotid artery. In recent years a syndrome, denominated as Eagle jugular syndrome, involving internal jugular vein (IJV) compression caused by an ESP has been proposed as a variation of Eagle syndrome. Clinical impact of the Eagle jugular syndrome on neurosurgical procedures has not been reported yet. Case Description: We present a case of a 68-year-old woman who underwent microvascular decompression for hemifacial spasm of the left side and developed delayed intracranial hemorrhage on postoperative day 3. We also demonstrate that this patient developed ipsilateral IJV stenosis between an ESP and the muscle bundle of the rectus capitis lateralis with antero-flexion neck position, which would induce venous congestion in addition to surgical disruption of emissary vein. Conclusion: This case is the first report demonstrating the association of an ESP with postoperative delayed intracranial hemorrhage. Our report elucidates the importance of the awareness among neurosurgeons of considering the ESP as an important bony anomaly, especially when planning for posterior fossa surgery.

Comparative anatomy and phylogenetic contribution of intracranial osseous canals and cavities in armadillos and glyptodonts (Xenarthra, Cingulata)

ABSTRACTThe evolutionary history of the Cingulata, as for many groups, remains a highly debated topic to this day, particularly for one of their most emblematic representatives: the glyptodonts. There is no consensus among morphological and molecular phylogenies relative to their position within Cingulata. As demonstrated by recent works, the study of the internal anatomy constitutes a promising path for enriching morphological matrices for the phylogenetic study of armadillos. However, internal cranial anatomy remains under-studied in the Cingulata. Here we explored and compared the anatomy of intracranial osseous canals and cavities in a diverse sample of extant and extinct cingulates, including the earliest well-preserved glyptodont crania. The virtual 3D reconstruction (using X-ray microtomography) of selected canals, i.e., the nasolacrimal canal, the palatine canal, the sphenopalatine canal, the canal for the frontal diploic vein, the transverse canal, the orbitotemporal canal, the canal for the capsuloparietal emissary vein and the posttemporal canal, and alveolar cavities related to cranial vascularization, innervation or tooth insertion allowed us to compare the locations, trajectories and shape of these structures and to discuss their potential interest for cingulate systematics. We tentatively reconstructed evolutionary scenarios for eight selected traits on these structures, in which glyptodonts often showed a greater resemblance to pampatheres, to the genus Proeutatus and/or to chlamyphorines. This latter pattern was partly congruent with recent molecular hypotheses, but more research is needed on these resemblances and on the potential effects of development and allometry on the observed variations. Overall, these comparisons have enabled us to highlight new anatomical variation that may be of great interest to further explore the evolutionary history of cingulates and the origins of glyptodonts on a morphological basis.

ANATOMICAL VARIATIONS OF FORAMEN OVALE AND CLINICAL SIGNIFICANCE

INTRODUCTION: The foramen ovale is present in sphenoid bone which transmits the mandibular nerve, accessory meningeal artery, emissary vein and the lesser petrosal nerve. This study was conducted on a total 100 si MATERIALS & METHODS: des in 50 dry adult skulls. The shape of foramen will be determined by a visual examination. Margins of foramen were carefully observed for the abnormal bony outgrowths such as sharp bony projections (spine), small blunt bony projection (tubercle), bony plate and bony bar. We obs RESULTS: erved the variations in shape of foramen ovale. We found oval, almond, round, triangular, slit like and irregular shaped in 62%, 20%, 9%, 4%, 3% and 2% foramina ovale respectively. We also observed abnormal bony outgrowths in the foramen ovale like spines, tubercles, bony plate and bony bar. Abnormal bony bar was dividing the foramen ovale in 2 compartments (Anterior and Posterior). The preci CONCLUSIONS: se knowledge of variations of foramen ovale is of valuable contribution for neurosurgeons to development of new and different techniques to approach the middle cranial fossa. In our study we found , 100% tubercles and 80% spines were arising from anterior margin of foramen ovale. These ndings are important for neurosurgeons to approach middle cranial fossa via foramen ovale for neurosurgical and diagnostic procedures like percutaneous biopsy of cavernous sinus tumours, electroencephalographic analysis, microvascular decompression , percutaneous trigeminal rhizotomy and administration of anaesthesia to the mandibular nerve. Surgeons should avoid to go , close to the anterior margin of foramen ovale as spines and tubercles could interrupt the procedures.

Parietal Foramen as A Landmark to Locate Intracranial Vascular and Parenchymal Structures

The aim of this study was to define the location of the parietal foramina (PF) with reference to skull landmarks and correlate the PF with cerebral and vascular structures to optimize neurosurgical procedures in the intracranial compartment. Two hundred and thirty-eight parietal bones studied by magnetic resonance imaging (MRI) of 119 patients were reviewed. The cephalometric points, inion, bregma, sagittal suture and lambda were used as anatomical references to locate the PF and define its anatomical relationships to parenchymal cerebral structures, especially some eloquent areas. The PF was identified in the MRI in 83 of the 119 individuals (69.7%) and was located at an average distance of 9.5 ± 0.8 cm (mean ± SD) posteriorly and 0.9 ± 0.3cm laterally to the Bregma. In over 90% of cases, the PF was located within a 2 cm radius of the bregma-PF distance’s mean value. Surgeons operating in the parietal region should be aware of the frequency of PF (69.7%), its location (superolateral to lambda) and its stable relationship with underlying anatomical structures. 88% of the 62 left PF’s were situated within 1cm, laterally to the left margin of the superior sagittal sinus (SSS). 60% of the right PF were situated within 1.3 cm laterally from the right margin of the SSS, while 40% were directly above the SSS. We propose that the PF should be used as the reference for the superior sagittal sinus during its course through the parietal lobe, as its constancy overtakes other commonly used landmarks (sagittal suture and midline). In conclusion, clinicians should be aware of the PF to both avoid iatrogenic injury to an emissary vein that courses through it that can lead to air embolism and as a guide to maneuvering through the parietal region.

Association between Foramen Size and Febrile Seizure Status in the Pediatric Population: A Two-Center Retrospective Analysis

Objective Febrile seizures have been shown to occur in 2 to 5% of children between the ages of 6 months and 5 years, making them the most common seizures of childhood. Multiple risk factors for febrile seizures have been identified; however, no investigation has been conducted to explore foramen size and associated venous drainage as a potential risk factor for experiencing febrile seizures. Of particular interest are the parietal foramen and the condylar canal, which conduct the parietal emissary vein and the occipital emissary vein, respectively. Emissary veins lack valves, allowing them to play a crucial role in selective brain cooling via a bidirectional flow of blood from the head’s evaporating surface. Narrowed cranial apertures conducting these veins may lead to reduced cerebral venous outflow and delayed brain cooling, creating favorable conditions for a febrile event. This study seeks to explore the association between cranial aperture area and febrile seizure status. Methods A retrospective cross-sectional medical record review study from January 2011 to December 2017 was conducted at a 500-bed academic hospital and a 977-bed private hospital in Lubbock, Texas, United States. A total of 101 complex febrile seizure patients were compared with a similarly aged group of 75 trauma patients representing the normal population. Parietal foramen area and condylar canal area were electronically measured and defined as having “normal” or “below normal” area. Statistical Analysis Independent t-tests were used to compare foramen and canal areas by febrile seizure status. Logistic regression analyses were conducted to determine the association of small cranial aperture area with febrile seizure status. Results Below normal parietal foramen area had a strong association with febrile seizures in our patient population. Male sex, white race, and complete vaccination status were also found to have significant associations with febrile seizure status. Conclusion Our findings indicated that narrowed parietal foramen may be considered as a risk factor for febrile seizure development.

Endovascular coiling of large mastoid emissary vein causing pulsatile tinnitus

The association of large mastoid emissary veins and pulsatile tinnitus has been reported. However, therapeutic options for this condition remain limited. We report a case of endovascular coiling of a large mastoid emissary vein in a patient with disabling pulsatile tinnitus with significant improvement of symptoms. To our knowledge, endovascular coiling of large mastoid emissary vein causing pulsatile tinnitus has not been reported.