Two =longitudinal spinal veins= or =sinuses= (Sinus columnæ vertebralis)
extend along the floor of the vertebral canal, one on either side of the
superior common ligament. They are continuous in front with the basilar
plexus. They lie in the grooves on the bodies of the vertebræ and are
connected by a series of transverse anastomoses which pass between the
central part of the bodies of the vertebræ and the superior common
ligament or in channels in the bone. They receive veins from the spinal
cord, the dura mater, and the bodies of the vertebræ (Venæ basis
vertebræ). Through the intervertebral foramina efferent vessels connect
with the vertebral, intercostal, lumbar, and lateral sacral veins.