Surgical importance of distance from mandibular condyle to carotid canal and foramen spinosum: an anatomical study

Background: The objective of this study was to compare the distance from mandibular condyle to internal carotid artery and middle meningeal artery.Methods: In this study 20 skulls obtained from the Department of Anatomy were utilized for the study. The following two parameters were measured using Vernier Caliper (digital). 1. Distance from Mandibular condyle to carotid canal 2. Distance from medial margin of Mandibular condyle to Foramen spinosum. All the measurements were taken thrice to minimize errors. Photograph of the skull base showing the measurements done was captured.Results: A total of 40 sides, 20 right and 20 left sides were studied. The mean distance between medial margin of mandibular condyle to carotid canal was 11.2 mm±0.6 on right side and 11.6mm±0.8 on left side. The mean distance from the medial margin of mandibular condyle to Foramen spinosum (middle meningeal artery) was 9.3 mm±1.1 on right side and 9.8mm±0.9 on left side. Conclusions: The distance between mandibular condyle to Middle meningeal artery is less compared to the distance between Mandibular condyle to carotid artery. The current study concludes that MMA is comparatively at high risk for damage compared to internal carotid artery.

An osteometric evaluation of the foramen spinosum and venosum / Una evaluación osteométrica de los forámenes espinoso y venoso

The foramen spinosum (FS) and foramen venosum (of Vesalius) (FV) are alisphenoid apertures situated within the hub of the middle cranial fossa in close proximity to foramen ovale (FO). The FS and FV provide a passage to important neurovascular structures. An accurate knowledge of the morphometric details of the FS and FV including their shape, incidence, relation to other foramina and/or presence of any anomalies may represent a reliable anatomical landmark during surgical explorative maneuvers. Therefore, the aim of this study was to investigate the morphologic and morphometric features of the FS and FV. The study was conducted on 100 dry human skulls (n= 200) obtained from the osteological bank at the University of KwaZulu-Natal, to produce a database which may serve as a useful guideline to surgeons and anesthetists. Although single (95%), duplicate (2.5%) and triplicate (0.5%) FS were identified; only single (5%) and duplicate (0.5%) FV were found. Oval (FS: 43.5%; FV: 4.5%) and round (FS: 58%; FV: 0.5%) foramina were observed. In addition, the relationship of the FS and FV to FO was recorded: postero-lateral (FS: 93%; FV: 0%); posterior (FS: 1.9%; FV: 0%); postero-medial (FS: 0.5%; FV: 0%); anterior (FS: 0%; FV: 0.5%); antero-medial (FS: 0%; FV: 4.5%). The mean morphometric parameters of the FS and FV included the internal diameter (FS: 2.53±0.76 mm; FV: 1.93±0.46 mm), external diameter (FS: 2.50±0.74 mm; FV: 2.81±1.53 mm) and distance to the FO (FS: 3.45± 1.29 mm; FV: 2.63±1.24 mm). In light of the morphometric and morphological variations of skull-based foramina, the evaluation of the FS and FV in our study may provide a reliable osteometric reference in clinical practice which may be beneficial during interpretation of imaging and surgical intervention.

El foramen espinoso (FE) y foramen venoso (FV) son aberturas situadas en el centro de la fosa craneal media en las proximidades de un foramen oval permeable (FO). El FE y FV proporcionan el acceso a importantes estructuras neurovasculares. Un conocimiento preciso de los datos morfométricos del FE y FV, incluyendo su forma, incidencia, relación con otros forámenes o presencia de cualquier anomalía puede representar un punto de referencia anatómica fiable durante las maniobras exploratorias quirúrgicas. El objetivo de este estudio fue investigar las características morfológicas y morfométricas del FE y FV. El estudio se realizó sobre 100 cráneos humanos secos (n= 200) obtenidos del banco osteológico de la Universidad de KwaZulu-Natal, para producir una base de datos que pueda servir como guía útil para los cirujanos y anestesistas. Se identificaron FE únicos (95%), dobles (2,5%) y triples (0,5%); junto a FV únicos (5%) y dobles (0,5%). Según forma, se encontraron forámenes de tipo oval (FE: 43,5%; FV: 4,5%) y circular (FE: 58%; FV: 0,5%). Además, se registró la relación entre FE, FV y FO: postero-lateral (FE: 93%; FV: 0%); posterior (FE: 1,9%; FV: 0%); postero-medial (FE: 0,5%; FV: 0%); anterior (FE: 0%; FV: 0,5%) y antero-medial (FE: 0%; FV: 4,5%). Los parámetros morfométricos medios de los FE y FV incluyeron el diámetro interno (FE: 2, 53±0,76 mm; FV: 1,93±0,46 mm), diámetro externo (FS: 2,50±0,74 mm; FV: 2,81±1,53 mm) y distancia al FO (FS: 3,45±1,29 mm; FV: 2,63±1,24 mm). Considerando la morfometría y las variaciones morfológicas de los forámenes en la base del cráneo, la evaluación del FE y FV puede proporcionar una referencia osteométrica fiable en la práctica clínica, que puede ser beneficiosa durante la interpretación imagenológica y la intervención quirúrgica.

An Anatomical Study of Foramen Spinosum in South Indian Dry Skulls with its Emphasis on Morphology and Morphometry.

Aim: To study themorphological details and to evaluate themorphometry of the Foramen Spinosum in the base of dry human skulls in South Indian population. Methods: 82 dry adult human skulls of unknown sex and of South Indian origin were obtained and variations in appearance were observed. The length and width of the Foramen Spinosum on both sides were determined using vernier calipers and area (A) was calculated and analyzed. Also, its mean distance from the midline on both the sides was noted and analyzed. Results: The values for the right side were 3.425± 0.637mm, 2.687± 0.487mm and 7.357 ± 2.195 mm2 and for the left side the values were 3.339 ± 0.660mm, 2.675 ± 0.465 mm and 7.110± 2.103 mm2 respectively, for the mean length,mean breadth andmean area of the Foramen Spinosum. Also, the shape of the Foramen Spinosum was typically round in most of the skulls studied (53.65%) and it was little away from midline on the left side. Conclusion: By analyzing the length, width and area of the Foramen Spinosum on both the sides, there was no statistical difference for the values obtained and these values were comparable with the studies done in the past.

Anatomical examination of the foramens of the middle cranial fossa / Examinación anatómica de los forámenes de la fosa craneal media

Three foramina can be identified in the greater wing of the sphenoid bone: The foramen rotundum (FR), foramen ovale (FO) and foramen spinosum (FS). In addition, there may be another foramen called foramen ovale accessorium or foramen vesalius (FV) which connects the middle cranial fossa to the fossa pterygoidea (pterygoid fossa). It is described as an opening with smooth walls in front and medial to foramen ovale which leads to an oblique channel directed towards the fossa pterygoidea. FV was present between FO and FR in 14 (31.8%) of 44 dry and 6 (33.3%) of 18 cadaver skullbase sides (total 20 (32.3%) of 62). The diameter values of foramens on both the right and the left side were observed to be almost symmetrical. FR's distance from the midline on the left side was greater than the right side. Also, the distance between FO and the petrous apex and the distance between FS and the petrous apex were greater on the left side. On the right side the distance between FO and FR, and the distance between FO and FS were greater. Also, the distance between FR and the petrous apex was greater on the right side. Anatomical variations in appearance size and distance of FR, FO, FS and FV are of great surgical importance. In conclusion, we can infer that the information provided with this study can help the neurosurgeon and anatomist to increase the knowledge about anatomy of middle cranial fossa.

Tres forámenes pueden ser identificados en el ala mayor del esfenoides: El foramen redondo (FR), foramen oval (FO) y el foramen espinoso (FS). Puede además existir otro foramen llamado foramen oval accesorio o foramen de Vesalio (FV), que conecta la fosa craneal media a la fosa pterigoidea. Se describe como una abertura con paredes lisas por anterior y medial al foramen oval, que conduce a un canal oblicuo dirigido hacia la fosa pterigoidea. FV estuvo presente entre FO y FR en 14 (31,8%) de 44 cráneos secos y 6 (33,3%), en 18 lados en la base de cráneos de cadáveres (total 20 (32,3%) de 62). El diámetro de los forámenes en los lados derecho e izquierdo se observó casi simétricos. Las distancias de FR desde la línea mediana en el lado izquierdo fue mayor que en el lado derecho. Además, la distancia entre FO y el vértice de la porción petrosa y la distancia entre el FS y el vértice porción petrosa fueron mayores en el lado izquierdo. En el lado derecho la distancia entre A y FR, así como la distancia entre A y FS fueron mayores. Por otra parte, la distancia entre los FR y el vértice del porción petrosa fue mayor en el lado derecho. Las variaciones anatómicas en el tamaño de la apariencia y la distancia de FR, DE, FS y FV son de gran importancia quirúrgica. Podemos inferir que la información proporcionada en este estudio puede ayudar al neurocirujano y anatomista para aumentar el conocimiento sobre la anatomía de la fosa craneal media.

Anatomic variants of foramen ovale and spinosum in human skulls / Variantes anatómicas de los forámenes oval y espinoso en cráneos humanos

Foramen ovale and spinosum are important foramina of the greater wing of the sphenoid. Normal variations in their shapes and sizes are quite common and widely studied. In the present study, conducted in the Department of Anatomy of School of Medical Sciences, Universiti Sains Malaysia, 25 dried human skulls were examined for anatomic variations of the foramina of the greater wing of the sphenoid. During the study, we noticed anatomic variations of the foramen ovale and spinosum. In one skull, there was an abnormally large and irregular foramen ovale which was confluent with the foramen spinosum. In the second skull, the foramen spinosum was absent on the left side and in the 3rd skull it was duplicated on the right side. These variations are very rare and may be of clinical and anatomical significance to neurosurgeons and physicians particularly in cases of trigeminal neuralgia, diagnostic detection of vascular tumors and aneurysm.

Los forámenes oval y espinoso son forámenes importantes del ala mayor del esfenoides. Variaciones normales en sus formas y tamaños son muy comunes y ampliamente estudiados. En el presente repórter, llevado a cabo en el Departamento de Anatomía de la Facultad de Ciencias Médicas, Universiti Sains Malaysia, fueron examinados en 25 cráneos humanos secos las variaciones anatómicas de los forámenes del ala mayor del esfenoides. Durante el estudio, se observaron algunas variaciones anatómicas de los forámenes oval y espinoso. En un cráneo, se observó un foramen oval anormalmente grande e irregular, que era confluente con el foramen espinoso. En el segundo cráneo, el foramen espinoso estaba ausente en el lado izquierdo y en el tercer cráneo se duplicó en el lado derecho. Estas variaciones son muy raras y pueden ser de importancia clínica y anatómica para neurocirujanos y médicos, en particular en casos de neuralgia del trigémino, detección diagnóstica de tumores vasculares y aneurismas.

Anatomic and morphometric consideration for external landmarks of foramen spinosum in Thai dry skulls.

Background and Objectives: The foramen spinosum (FS) is an important opening on the greater wing of the sphenoid bone and transmits the middle meningeal artery to the middle cranial fossa. Because the presence of FS is important in microsurgery of this area, the anatomic and morphometric consideration for localizing the FS using external landmarks were studied. Methods: One hundred and three dry skulls were examined for the FS in the middle cranial fossa and at the extracranial view of the skull base. The type of FS was classified according to its shape. Its diameter and the distances to the zygomatic arch (ZA) and the external acoustic meatus (EAM) were also measured. Results: The FS in both views of the skull base was mostly round in shape (43.2% intracranially and 49.5% extracranially) and was present bilaterally 30.1% extracranially. The maximum and minimum diameters of the FS and the FS-ZA distance were greater in males than females and the ZA-EAM distance was greater on the right than the left sides significantly. (P<0.05) Conclusion: Although a great variation was found in the shapes of the FS, prior estimation of the location of FS was suggested using external landmarks as the point on the ZA 16.42 mm anterior to the EAM and 34.19 mm from that point medial and perpendicular to the ZA. These findings may help neurosurgeon to approach the middle cranial fossa more precisely and gain better preservation of surrounding neurovascular structures.