The internal vertebral venous plexuses (intraspinal veins) lie within the

vertebral canal In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the dorsal bony arches of the vertebral column, which contains the spinal cord, spinal roots and dorsal root ganglia. It is a proc ...

in the

epidural space In anatomy, the epidural space is the potential space between the dura mater and vertebrae ( spine). The anatomy term "epidural space" has its origin in the Ancient Greek language; , "on, upon" + dura mater also known as "epidural cavity", "e ...

, embedded within epidural fat. They receive tributaries from bones,

red bone marrow Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic c ...

, and

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

. They are arranged into four interconnected, vertically oriented vessels - two situated anteriorly, and two posteriorly: *The anterior internal vertebral venous plexus consists of two large plexiform veins situated upon the posterior surfaces of the vertebral bodies and

intervertebral discs An intervertebral disc (British English), also spelled intervertebral disk (American English), lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint (a symphysis), to allow slight movement of the ver ...

on either side of the

posterior longitudinal ligament The posterior longitudinal ligament is a ligament connecting the posterior surfaces of the vertebral bodies of all of the vertebrae of humans. It weakly prevents hyperflexion of the vertebral column. It also prevents posterior spinal disc hernia ...

(underneath this ligament they are interconnected by transverse branches into which the basivertebral veins open). * The posterior internal vertebral venous plexus consists of two veins situated - one on either side - upon the anterior aspect of the

vertebral arches Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

and

ligamenta flava The ligamenta flava (: ligamentum flavum, Latin for ''yellow ligament'') are a series of ligaments that connect the ventral parts of the laminae of adjacent vertebrae. They help to preserve upright posture, preventing hyperflexion, and ensuring ...

. They form

anastomoses An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection may be ...

with posterior external plexuses by way of veins passing through or between the ligamenta flava. The anterior and posterior internal plexuses communicate via a series of venous rings - one near each vertebra. Due to these interconnections, the anterior and posterior internal plexuses were formerly considered a single vascular unit - the ''retia venosa vertebrarum''.

Anatomy

The internal vertebral venous plexuses are composed of valveless veins. They form a denser vascular network than the external vertebral venous plexuses. The basivertebral veins are the main tributaries of the plexus.

Anastomoses

They forms venous anastomoses through

intervertebral foramina The intervertebral foramen (also neural foramen) (often abbreviated as IV foramen or IVF) is an opening between (the intervertebral notches of) two pedicles (one above and one below) of adjacent vertebra in the articulated spine. Each interve ...

by way of intervertebral veins at all vertebral levels. Around the

foramen magnum The foramen magnum () is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblongata, passes thro ...

, they form a dense venous network with the

vertebral veins The vertebral vein is formed in the suboccipital triangle, from numerous small tributaries which spring from the internal vertebral venous plexuses and issue from the vertebral canal above the posterior arch of the atlas. They unite with small ...

sigmoid sinus The sigmoid sinuses (sigma- or s-shaped hollow curve), also known as the , are paired dural venous sinuses within the skull that receive blood from posterior transverse sinuses. Structure The sigmoid sinus is a dural venous sinus situated withi ...

es,

occipital sinus The occipital sinus is the smallest of the dural venous sinuses. It is usually unpaired, and is sometimes altogether absent. It is situated in the attached margin of the falx cerebelli. It commences near the foramen magnum, and ends by draining in ...

es, the basilar plexus, the condyloid emissary veins, and the rete canalis hypoglossi. The

Batson venous plexus The Batson venous plexus (Batson veins) is a network of valveless veins in the human body that connect the deep pelvic veins and thoracic veins (draining the inferior end of the urinary bladder, breast and prostate) to the internal vertebral ven ...

, which communicates the posterior intercostal vessels with the vertebral plexus, lacks valves so blood can flow in both directions. The clinical importance of this venous communication is that it represents an important phase in the establishment of vertebral metastases and neuroschistomiasis.Carbonell C, Rodríguez-Alonso B, López-Bernús A, Almeida H, Galindo-Pérez I, Velasco-Tirado V, Marcos M, Pardo-Lledías J, Belhassen-García M. Clinical Spectrum of Schistosomiasis: An Update. J Clin Med. 2021 Nov 25;10(23):5521. doi: 10.3390/jcm10235521. PMID 34884223; PMCID: PMC8672275.

References

External links

* - "Venous Drainage of the Vertebral Column" Thoracic veins Veins of the torso {{circulatory-stub