part of part of tributary of tributary of Homo sapiens head internal jugular vein sigmoid sinus https://upload.wikimedia.org/wikipedia/commons/b/bd/Gray488_blue.gif Wikipedia:Sigmoid_sinus EHDAA2:0001838 EMAPA:19060 UBERON:0005475 sulcus sigmoideus EHDAA:9880 The sigmoid sinuses, within a human head, are 2 areas beneath the brain, which allow blood veins to span the area, from the center of the head downward. They drain from the transverse sinuses (under the back of the brain) to the internal jugular vein. Each sigmoid sinus begins beneath the temporal bone and follows a tortuous course to the jugular foramen, at which point the sinus becomes continuous with the internal jugular vein[Wikipedia:Sigmoid_sinus]. SCTID:279264003 VHOG:0001337 ncithesaurus:Sigmoid_Sinus FMA:50782 A portion of the lateral venous sinus, bulging prominently into the mastoid cavity, that serves as a principal conduit by which blood leaves the cranium[EPIC]. The sigmoid is drained by the internal jugular vein. paired venous dural sinus