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The Governor Vessel (GV)
Published in Narda G. Robinson, Interactive Medical Acupuncture Anatomy, 2016
Posterior external vertebral venous plexus: Venous circulation of the spine exists as a dense vertebral venous network that provides drainage for the vertebrae and for epidural and paraspinous tissues, including fat and muscle. The veins comprising this network, or plexus, are thin-walled and valveless. They drain venous blood from the marrow space within the vertebrae and from the capillaries of their cartilaginous endplates. Closely linked internal and external vertebral venous plexuses envelop the interior and exterior spinal column and freely communicate with one another. The internal vertebral venous plexus resides within the vertebral canal while the external plexus resides outside of the canal. Each plexus has anterior and posterior components. The posterior external vertebral venous plexus may receive venous drainage from the vertebral bodies themselves. Veins emanating from the network accompany the spinal nerves as intervertebral veins that exit the intervertebral foramina; these may serve as collateral generators of radicular pain.3 Communications also exist between the veins of the spinal cord and the vertebral, posterior intercostal, lumbar, and lateral sacral veins.
Spinal Cord Angiography
Published in Milosh Perovitch, Radiological Evaluation of the Spinal Cord, 2019
The technique of spinal phlebography commonly used was described by Fischgold and co-workers in 1952. It consisted of an intraosseous injection of the contrast medium either into the spinous process or into the vertebral body after the puncture of the bone by means of a large needle or trocar. This method was a relatively simple technique that enabled the opacification of the lumbar, dorsolumbar, and cervical venous spinal plexuses.59 Some investigators considered the spinal venography to be a useful diagnostic procedure in case of disk herniations and tumors located in the epidural space. Equally, it was applied in cases of congenital spinal anomalies, intradural neoplasms, primary or secondary tumors of the vertebrae, and meningeal adhesions.59, 65, 66 Later, transfemoral ascending lumbar catheterization of the epidural veins was introduced as a more accurate procedure.64 A catheter is inserted through the femoral vein using the Seldinger technique into the corresponding ascending lumbar vein. A bilateral lumbar vein catheterization was performed originally with end-hole catheters. However, it became evident that a unilateral catherization of the lumbar vein, and injection of the contrast medium resulted in a complete opacification of the epidural venous plexus on both sides. From 20 to 40 cc of the contrast material is injected if a single catheter is used, and about 25 to 30 cc per catheter is used if bilateral injections are performed. The injection is carried out at the rate of approximately 5 cc/ sec. A biplane seriography is done following the injection of the contrast medium. Usually, one film per second is exposed for 10 sec. Some authors observed that the best filling of the epidural veins was achieved if a selective injection was performed into an intervertebral vein, particularly at the level L5 to S1. With this type of injection, a very good visualization of the epidural and intervertebral veins is obtained at all levels. If the injection of the contrast medium is done in this way, there is little over-flow into the systemic veins, and the external abdominal compression and Valsalva’s maneuver will not be necessary. Some type of obstruction to the flow of blood in the vena cava either by compression or different maneuvers was purposefully applied by some examiners to reduce the outflow of the contrast medium from the lumbar veins into the iliac veins or the caval vein.67 Transfemoral lumbar epidural phlebography has been increasingly employed as a diagnostic tool in diseases of lumbar disk. Although the transfemoral approach results in a more consistent visualization of the veins of the vertebral canal, errors in interpretation of venograms can occur, and a misleading diagnosis of a disk prolapse can be made in the presence of an insufficient filling of the epidural veins by the contrast medium.67
Relationship between length and width of the purple line and foetal head descent in active phase of labour
Published in Journal of Obstetrics and Gynaecology, 2018
Morvarid Irani, Masoumeh Kordi, Habibollah Esmaily
Bryne and Edmonds (Byrne and Edmonds 1990) supposed that the purple line appeared due to increasing intrapelvic pressure as the foetal head descends causing vasocongestion in the basivertebral and intervertebral veins of the sacrum which along with a lack of subcutaneous tissue in this area resulted in the line of purple colouration; however the aetiology of the purple line is unknown. This possible explanation may account for the correlation seen in the present study between station of the foetal head and length of the purple line.