An anatomical study of the suboccipital cavernous sinus and its relationship with the myodural bridge complex.

The suboccipital cavernous sinus (SCS) and the myodural bridge complex (MDBC) are both located in the suboccipital region. The SCS is regarded as a route for venous intracranial outflow and is often encountered during surgery. The MDBC consists of the suboccipital muscles, nuchal ligament, and myodural bridge and could be a power source for cerebrospinal fluid circulation. Intracranial pressure depends on intracranial blood volume and the cerebrospinal fluid. Since the SCS and MDBC have similar anatomical locations and functions, the aim of the present study was to reveal the relationships between them and the detailed anatomical characteristics of the SCS. The study involved gross dissection, histological staining, P45 plastination, and three-dimensional visualization techniques. The SCS consists of many small venous sinuses enclosed within a thin fibrous membrane that is strengthened by a fibrous arch closing the vertebral artery groove. The venous vessels are more abundant in the lateral and medial portions of the SCS than the middle portion. The middle and medial portions of the SCS are covered by the MDBC. Type I collagen fibers arranged in parallel and originating from the MDBC terminate on the SCS either directly or indirectly via the fibrous arch. The morphological features of SCS revealed in this research could serve as an anatomical basis for upper neck surgical procedures. There are parallel arrangements of type I collagen fibers between the MDBC and the SCS. The MDBC could change the blood volume in the SCS by pulling its wall during the head movement.

A comparative study of the morphology of suboccipital cavernous sinus using magnetic resonance imaging and cast specimens / Un estudio comparativo de la morfología del seno cavernoso suboccipital utilizando imágenes de resonancia magnética y muestras de yeso

SUMMARY: A comparative study of the morphology of suboccipital cavernous sinus (SCS) using MRI and cast specimens was performed. The present retrospective study analysed the craniocervical magnetic resonance venography (MRV) imaging data of 61 patients. Three-dimensional reconstruction was performed using Mimics 19.0. The SCS left-right diameter(d1), distance from the midline (d2), supero-inferior diameter(d3), anteroposterior diameter (d4), distance from posterior diameter to skin (d5), and diameter of the SCS at different parts (d6-d8) were measured. Comparison between MRV images and cast specimens, the SCS, marginal sinus, anterior condylar vein, and vertebral artery venous plexus were symmetrical and could be bilaterally displayed, whereas the presence of extra condylar vein and posterior condylar vein exhibited different types. The adjacency between the SCS and its communicating vessels and changes in its communicating vessels corresponded well with the MRV images and cast specimens. Many types of the presence of left and right lateral condylar and posterior condylar veins were found in the cast specimens, which could be divided into the bilateral presence of posterior condylar and lateral condylar veins, unilateral presence of posterior condylar veins, and unilateral presence of lateral condylar vein. A total of 61 cases analysed using MRV images revealed the bilateral presence of posterior condylar and lateral condylar veins (77.1 %), the unilateral presence of posterior condylar vein (18.0 %), and the unilateral presence of lateral condylar vein (9.8 %), of which the bilateral presence of posterior condylar and lateral condylar veins accounted for the largest proportion. MRV images and cast specimens of the SCS showed its normal morphological structure and adjacency, thus providing accurate and complete Three-dimensional imaging anatomical data of the SCS and its communicating vascular structures. This study enriches the Chinese SCS imaging anatomy data and may be valuable in clinical practice.

RESUMEN: Se realizó un estudio comparativo de la morfología del seno cavernoso suboccipital (SCS) mediante resonancia magnética y muestras de yeso. El presente estudio retrospectivo analizó los datos de imágenes de venografía por resonancia magnética (RNM) craneocervical de 61 pacientes. La reconstrucción tridimensional se realizó con Mimics 19.0. Se midió: el diámetro izquierdo-derecho del SCS (d1), la distancia desde la línea mediana (d2), el diámetro superoinferior (d3), el diámetro anteroposterior (d4), la distancia desde el diámetro posterior hasta la piel (d5) y el diámetro del SCS en diferentes partes (d6-d8). En la comparación entre las imágenes RNM y las muestras de yeso, el SCS, el seno marginal, la vena condilar anterior y el plexo venoso de la arteria vertebral eran simétricos y se observaron bilateralmente, mientras que la presencia de la vena extracondilar y la vena condilar posterior presentaba tipos diferentes. La proximidad del SCS y sus vasos comunicantes y los cambios en sus vasos comunicantes se correspondieron bien con las imágenes de RNM y los especímenes moldeados. Se encontraron muchos tipos de venas condilares laterales y condilares posteriores izquierda y derecha en las muestras de yeso, que podrían dividirse en presencia bilateral de venas condilares posteriores y condilares laterales, presencia unilateral de venas condilares posteriores y presencia unilateral de venas condilares laterales. Un total de 61 casos analizados mediante imágenes MRV revelaron la presencia bilateral de venas condilares posteriores y condilares laterales (77,1 %), la presencia unilateral de venas condilares posteriores (18,0 %) y la presencia unilateral de venas condilares laterales (9,8 %) de los cuales la presencia bilateral de las venas condilar posterior y condilar lateral representó la mayor proporción. Las imágenes de RNM y las muestras de yeso del SCS mostraron su estructura morfológica y adyacencia normales, lo que proporcionó datos anatómicos de imágenes tridimensionales precisos y completos del SCS y sus estructuras vasculares comunicantes. Este estudio enriquece los datos de anatomía de imágenes de SCS chino y puede ser valioso en la práctica clínica.