Prevalencia y características morfométricas del foramen venoso en cráneos del Noreste de México / Prevalence and morphometric characteristics foramen venosum in Northeastern Mexico skulls

El foramen venoso es una estructura inconstante que se encuentra posterior al foramen redondo y medial al foramen oval, y da paso a una vena que anastomosa al plexo venoso pterigoideo con el seno cavernoso. La existencia de éste foramen puede ser motivo de complicaciones clínicas, entre ellas que es una potencial vía de acceso al seno cavernoso de trombos infectados y constituye una posible falsa vía durante la rizotomía percutánea del trigémino pudiendo puncionar la vena y ocasionar hematomas subdurales. Se utilizó la colección de cráneos del Departamento de Anatomía de la Facultad de Medicina UANL. Se observó la frecuencia y se midieron los siguientes parámetros del foramen: Ancho y largo; en la cara interna de la base del cráneo se midieron las distancias a: foramen redondo, foramen oval, plano sagital mediano y entre forámenes venosos; en la cara externa de la base del cráneo se midieron las distancias con: foramen oval, plano sagital medio y entre los forámenes venosos. Las medidas fueron llevadas a cabo por tres observadores distintos a través de medición directa con vernier y con microfotografías con escalas milimétricas. Se encontró una frecuencia del 20 por ciento con medidas medias de 1,66mm de largo, 1,06mm de ancho; en la cara interna de la base del cráneo: 11,31mm de distancia al foramen redondo, 4,13mm al foramen oval, 17,75mm al plano sagital medio y 31,91mm entre los forámenes; en la cara externa de la base: 2,50mm al foramen oval, 19,54mm al plano sagital medio y 36,05mm entre forámenes venoso. La distancia al foramen oval varía en la cara interna y la cara externa de la base del cráneo debido a un trayecto oblicuo del foramen que tiende a aproximarse al foramen oval y por tanto a separarse del plano sagital medio. Los forámenes derechos fueron generalmente más grandes.

Foramen venosum (foramen Vesalius) is an inconstant structure which is located posterior to the foramen rotundum and medial to the foramen ovale, and it gives pace to an emissary vein that communicates the plexus pterigoideus and the sinus cavernosus. The existence of this anatomical structure can be of interest in certain procedures like percutaneous trigeminal rhizotomy where this foramen can be the cause of a false pathway and be punctured causing a subdural hematoma. It also can be an access to the sinus cavernosus for infected thrombus coming from dental and facial infections. For this study the skull collection of the Anatomy Department, Faculty of Medicine UANL, was used. We observed the frequency and measured the following parameters: Length and width; in the basis cranii we measured: Distances to the foramen rotundum, foramen ovale, planum medianum and between two foramina venosum (one on each side). In basis cranii externa we measured: distances to foramen ovale, planum medianum, and between two foramina venosum. Three independent observers blinded among them, measured the parameters using a Vernier and microphotographs with milimetrical scales. A 20 percent frequency was found and the following median measures: Length 1.66mm, width 1.06mm; basis cranii: distance to foramen rotundum 11.31mm, distance to foramen ovale 4.13mm, distance to planum medianum 17.75mm and 31.91mm between both foramina venosum. Basis cranii externa: distance to foramen ovale 2.49mm, distance to planum medianum 19.54mm and distance between foramenina venosum 36.05. The distance to the foramen ovale varies between basis cranii and basis cranii externa because the foramen has an oblique trajectory and it approximates to the foramen ovale (from superior to inferior) and separates from the planum medianum. It was found bilaterally only in one skull. There are differences between the left and right foramens, the latter being generally larger.

A quantitative and descriptive approach to morphological variation of the endocranial base in modern humans.

The cranial base is one of the major foci of interest in functional craniology. The evolution and morphogenesis of this structure are still poorly known and rather controversial because of multifactorial influences and polyphasic stages. Endocranial dynamics are associated anteriorly with the upper facial structures, laterally with the mandibular system and midsagittally with brain development. In the present study, we investigated the endocranial morphology of modern humans using 3D landmark-based approaches, i.e. geometric morphometrics and Euclidean distance matrix analysis. The structure of endocranial variation is poorly integrated, with only weak reciprocal influences among the three fossae. Some major variations are associated with changes in the posterior fossa, with possible consequences on the anterior areas. These main patterns of integration are hypothesized to be influenced by the connective tensors of the dura layers. Static allometry and sex differences are largely related to the ontogenetic sequences, characterized by early maturation of the anterior fossa with respect to the middle and posterior regions (i.e., relatively shorter posterior part of the planum sphenoideum and vertical lengthening of the clivus in males). The relative independence between the endocranial fossae, as well as their structural connection through the meningeal tensors, must be carefully considered in studies on the evolutionary dynamics, since they lead to mosaic changes through phylogeny.

Assessment of mandibular growth and response to orthopedic treatment with 3-dimensional magnetic resonance images.

INTRODUCTION: Three-dimensional (3D) craniofacial images are commonly used in clinical studies in orthodontics to study developmental and morphologic relationships. METHODS: We used 3D magnetic resonance imaging to study relationships among craniofacial components during the pubertal growth spurt and in response to Fränkel appliance therapy. The sample for this prospective study was 156 high-resolution magnetic resonance images with 1 mm isotropic voxel resolution of 78 subjects taken initially (T1) and 18 +/- 1 months (T2) after treatment or an observation period. The subjects were Brazilian children; 28 were treated and 25 were untreated for Class II malocclusion, and 25 were untreated with normal occlusions. A Procrustes geometric transformation of 3D skeletal landmarks was used to assess growth or treatment alterations from T1 to T2. The landmarks were located on the mandibular rami and the other craniofacial parts specifically related to the mandibular growth (the middle cranial fossae and the posterior part of the bilateral nasomaxilla). This allowed visualization of the entire volumetric dataset with an interactive 3D display. RESULTS: Statistically significant differences were found in the relative 3D skeletal growth directions from T1 to T2 for treated vs untreated Class II children (Bonferroni-adjusted P < .001) and for treated Class II vs normal-occlusion subjects ( P < .001). The major differences in the treated group were increased mandibular rami vertical dimensions and more forward rami relative to the posterior nasomaxilla and the middle cranial fossae. Principal component analysis made it possible to show individual variability and group differences in the principal dimensions of skeletal change. CONCLUSIONS: These methods are generalizable to other imaging techniques and 3D samples, and significantly enhance the potential of systematically controlled data collection and analysis of bony structures in 3 dimensions for quantitative assessment of patient parameters in craniofacial biology.

Comparison of relative mandibular growth vectors with high-resolution 3-dimensional imaging.

INTRODUCTION: The mandibular rami and their endochondrally growing condyles develop in many directions relative to the variable anatomic patterns of the nasomaxilla and middle cranial fossae during growth and response to orthopedic treatment. METHODS: High-resolution magnetic resonance images were used to compare 3-dimensional (3D) growth vectors of skeletal displacement and bone remodeling in 25 untreated subjects with Class II malocclusions, 28 subjects with Class II malocclusions who were treated with Fränkel appliance therapy, and 25 subjects with normal occlusions. Marked differences were noted over an 18-month observation period. The 3D coordinates of anatomic landmarks were registered by Procrustes fit to control for rotation, translation, and scale differences. RESULTS: Compared with untreated Class II and normal-occlusion subjects, the treated group showed highly significant differences in the 3D displacement/remodeling vectors of gonion and pterygomaxillary fissure relative to condylion and middle cranial fossae bilateral skeletal landmarks, by using both permutation tests ( P < .001) and a general linear multivariate model ( P < .0001). CONCLUSIONS: In a prospective and systematically controlled study, we quantitatively described significant 3D rami skeletal compensations in the structural assembly of facial morphogenesis at the beginning of the adolescent growth spurt using novel modeling techniques. These techniques have facilitated quantification of relative 3D growth vectors to illustrate skeletal changes with Fränkel appliance therapy. Future studies are required to assess the long-term clinical significance of our findings.