Libelle of note

Several Sinus durae matris have been added: 1) Sinus tentorii (Tentorial sinus; see Matsushima M, Suzuki SO, Fukui M, et al. 1989 Microsurgical anatomy of the tentorial sinuses. J Neurosurg 71:923-928); 2) A variable Sinus occipitalis obliquus (Oblique occipital sinus; see Tubbs RS, Bosmia An, Shoja MM, et al. 2011 The oblique occipital sinus: A review of anatomy and imaging characteristics. Surg Radiol Anat 33:747-749); 3) A variable Plexus venosus falcis (Venous plexus of falx; see Tubbs RS, Loukas M, Shoja MM, et al. 2007 Anatomy of the falcine venous plexus. J Neurosurg 107:155-157); 4) A variabe Sinus intercavernosus inferior (Inferior intercavernous sinus; see Tubbs RS, Griessenauer C, Loukas M, Cohen-Gadol A 2014 Circular sinus: An anatomical study with neurosurgical and neurointerventional applications. World Neurosurg 82:475-478).

Under pathological conditions, venovenous ‘bypasses’ open to decrease hypertension in the portal vein system. These are enlarged existing venovenous anastomoses: Portocaval anastomoses. The following major routes can be distinguished (Luzsa G 1972 Röntgenanatomie des Gefäßsystems. Akadémiai Kiadó, Budapest; Kachlik et al. 2021 Bosn J Basic Med Sci 21:208-220).

Between tributaries of the left gastric vein and the oesophageal veins.

Between tributaries of the superior rectal vein and the middle and inferior rectal veins.

Between the paraumbilical veins and tributaries of the superficial eipgastric and thoracoepigastric veins.

Between the paraumbilical veins and tributaties of the inferior and superior epigastric veins within both rectus abdominis muscles.

Between the paraumbilical veins and tributaries of the vesical venous plexus running in the midline along the median umbilical ligament.

Between veins of the spleen and retroperitoneal veins and veins of the posterior abdominal wall.

Between veins of the hepatic capsule and veins of the diaphragm at the area nuda hepatis.

Under pathological conditions, such as hypertension in one of the venae cavae, anastomoses cavocavales ( venovenous ‘bypasses’) open to relieve hypertension. The following groups can be distinguished (Luzsa G 1972 Röntgenanatomie des Gefäßsystems. Akadémiai Kiadó, Budapest; Kachlik et al. 2021 Bosn J Basic Med Sci 21:208-220).

Between tributaries of the superficial epigastric veins and those of the thoracoepigastiv veins within the subcutaneous layer of the anterolateral body wall.

Between tributaries of the inferior epigastric veins and those of the superior epigastric veins within the rectus abdominis muscle.

Between tributaries of the lumbar veins and those of the ascending lumbar veins draining into the azygos and hemiazygos veins

Between tributaries of the vertebral venous plexuses, extending along the vertebral column and within the vertebral canal.

Between the inferior mesenteric vein and the middle and inferior rectal veins.