The basivertebral veins are located within the vertebral bodies of the spine. They arise from the central part of the vertebral bodies and pass through the substance of the bone, draining into the internal vertebral venous plexus. These veins are part of the venous network that supplies the vertebral column, specifically within the cancellous bone of each vertebra. The basivertebral veins emerge through the posterior surface of the vertebral bodies, typically in the midline, and are closely associated with the venous drainage of the vertebral column. They are an important component of the vertebral venous system, linking the venous drainage of the vertebrae to larger venous structures.
Structure and Anatomy
Location
The basivertebral veins are located within the vertebral bodies of the spine, primarily running through the central, cancellous (spongy) portion of each vertebra. These veins are part of the internal venous system that provides drainage for the vertebral bodies and are found throughout the vertebral column, from the cervical region down to the sacral region. The basivertebral veins emerge from the posterior surface of the vertebral bodies, usually at a central point, and drain into the internal vertebral venous plexus, which lies within the epidural space of the vertebral canal.
Structure
The basivertebral veins are large, centrally located veins that run through the spongy bone of the vertebral bodies. Each vertebral body has a single, centrally positioned basivertebral vein that extends from the anterior part of the vertebral body through the posterior wall, typically emerging near the midline of the posterior surface of the vertebral body. The structure of these veins allows them to drain blood from the bone tissue (cancellous bone) of the vertebral bodies into the surrounding venous plexus. The basivertebral veins communicate with both the internal vertebral venous plexus and the surrounding smaller venous channels within the vertebral body.
Origin
The basivertebral veins arise from small venous channels within the cancellous bone of the vertebral bodies. These small veins coalesce to form the larger basivertebral veins, which are centrally located within the vertebrae. The veins originate deep within the substance of the vertebral body, providing drainage for the bone itself. The venous channels within the vertebral body converge toward the center, forming the basivertebral vein as it moves posteriorly through the vertebral body.
Course
The basivertebral veins run from the central portion of the vertebral body to the posterior surface. They typically emerge from the posterior wall of the vertebral body, near the center, and pass through small bony foramina (holes) or openings in the posterior surface of the vertebrae. Once they exit the vertebral body, the basivertebral veins join the larger venous system, particularly the internal vertebral venous plexus, which is located in the epidural space surrounding the spinal cord and within the vertebral canal. The course of the basivertebral veins is consistent throughout the vertebral column, from the cervical vertebrae down to the lumbar and sacral regions.
Relations
- Anterior relations: The basivertebral veins are situated deep within the vertebral body, surrounded by cancellous bone. Anteriorly, they are related to the anterior longitudinal ligament and the anterior surface of the vertebral body.
- Posterior relations: Posterior to the basivertebral veins lies the vertebral canal, which houses the spinal cord and the internal vertebral venous plexus. The veins emerge from the posterior wall of the vertebral body and drain into this venous plexus.
- Lateral relations: The basivertebral veins are bordered laterally by the pedicles of the vertebrae, which connect the vertebral body to the posterior elements of the spine. Lateral to the basivertebral veins, smaller venous branches drain the surrounding bone.
- Superior and inferior relations: The basivertebral veins are located centrally within each vertebral body, and their superior and inferior boundaries are formed by the intervertebral discs, which separate adjacent vertebral bodies.
Communication with the Internal Vertebral Venous Plexus
The basivertebral veins play a central role in connecting the venous drainage of the vertebral bodies to the internal vertebral venous plexus, which is located in the epidural space of the vertebral canal. This venous plexus forms a network of interconnected veins that run along the length of the spinal canal, both anteriorly and posteriorly, providing a pathway for venous blood to be drained from the vertebral column. The basivertebral veins join the internal vertebral venous plexus by passing through the posterior wall of the vertebral body and entering the epidural space.
Tributaries
The basivertebral veins receive blood from smaller venous channels within the cancellous bone of the vertebral bodies. These smaller veins drain the bone marrow and the surrounding bone tissue, converging toward the central part of the vertebra to form the larger basivertebral veins. In addition to these intraosseous tributaries, the basivertebral veins may also communicate with small venous branches that emerge from the intervertebral discs and adjacent bony structures.
Termination
The basivertebral veins terminate by draining into the internal vertebral venous plexus, which is located in the epidural space surrounding the spinal cord. Once the basivertebral veins exit the vertebral body through the posterior wall, they join this venous plexus, which provides a route for venous blood to leave the vertebral column. The internal vertebral venous plexus is connected to larger systemic venous structures, such as the azygos vein, the segmental veins, and the vertebral veins, which ultimately return the blood to the heart.
Surrounding Structures
- Anteriorly: The basivertebral veins are surrounded by the cancellous bone of the vertebral body and are located anterior to the internal vertebral venous plexus.
- Posteriorly: Posterior to the basivertebral veins lies the vertebral canal, which contains the spinal cord, the spinal meninges, and the internal vertebral venous plexus.
- Laterally: Lateral to the basivertebral veins are the pedicles of the vertebrae, which provide structural support to the vertebral arch and connect the vertebral body to the posterior elements of the spine.
- Superior and inferior relations: The superior and inferior surfaces of the vertebral body, where the basivertebral veins are located, are in contact with the adjacent intervertebral discs and the vertebral bodies above and below.
Variations
The anatomy of the basivertebral veins can show anatomical variations in size, shape, and drainage patterns. In some individuals, the basivertebral veins may be larger or more prominent, depending on the size and vascularization of the vertebral body. The foramina through which the veins emerge in the posterior vertebral body may also vary slightly in size and position. Additionally, the communication between the basivertebral veins and the internal vertebral venous plexus can show variation in terms of the number and size of the connecting veins.
Function
Venous Drainage of the Vertebral Bodies
The primary function of the basivertebral veins is to drain venous blood from the vertebral bodies. The vertebral bodies are the large, cylindrical portions of the vertebrae that bear the weight of the spine. They are composed of cancellous (spongy) bone, which contains a network of small blood vessels, including venous channels. The basivertebral veins collect deoxygenated blood from these small venous channels within the cancellous bone and transport it out of the vertebral bodies. This drainage prevents the buildup of blood and maintains proper circulation within the vertebrae.
Removal of Metabolic Waste from Bone Tissue
The basivertebral veins play a crucial role in the removal of metabolic waste products from the vertebral bodies. Like any other tissue, bone tissue generates waste products during normal metabolic processes. These include byproducts of cellular respiration, such as carbon dioxide and other waste materials. The basivertebral veins ensure that these waste products are efficiently removed from the vertebral bodies by carrying deoxygenated blood away from the bone tissue. This function is essential for maintaining the health of the vertebrae and ensuring that the bone tissue can continue to function optimally.
Contribution to the Internal Vertebral Venous Plexus
The basivertebral veins are a key component of the internal vertebral venous plexus, a network of veins located in the epidural space that surrounds the spinal cord. By draining blood from the vertebral bodies into the internal vertebral venous plexus, the basivertebral veins help maintain proper venous circulation within the vertebral column. The internal vertebral venous plexus provides a pathway for blood to travel from the vertebrae to larger venous structures, such as the vertebral veins, azygos vein, and segmental veins, which ultimately return the blood to the heart.
Support for Venous Return During Movement
The vertebral column is a dynamic structure that undergoes constant movement, including flexion, extension, and rotation. The basivertebral veins play an important role in supporting venous return during these movements. As the spine moves, pressure within the vertebral bodies can fluctuate, and the basivertebral veins must adapt to these changes in pressure. The venous network formed by the basivertebral veins, along with the internal vertebral venous plexus, allows for the redistribution of blood within the vertebral column, ensuring that venous return is maintained even during spinal motion. This adaptability prevents venous congestion and maintains proper blood flow.
Pressure Regulation within the Vertebral Bodies
The basivertebral veins are also involved in regulating pressure within the vertebral bodies. Bone tissue requires a delicate balance of pressure to maintain healthy circulation and avoid conditions like venous stasis (blood pooling). The basivertebral veins help regulate this pressure by providing a pathway for blood to exit the vertebral bodies and enter the internal vertebral venous plexus. By maintaining consistent venous outflow, the basivertebral veins help stabilize the internal environment of the vertebral bodies, ensuring that blood flow and pressure remain within normal limits.
Connection with Other Venous Systems
The basivertebral veins also serve to connect the venous drainage of the vertebral bodies with other venous systems in the spine, particularly the internal and external vertebral venous plexuses. The internal vertebral venous plexus runs within the spinal canal, while the external vertebral venous plexus is located outside the vertebrae. The basivertebral veins provide a conduit for venous blood to flow from the vertebral bodies into these larger venous networks. This connection ensures that blood can be efficiently drained from the vertebrae and transported to the systemic venous circulation.
Venous Drainage from the Bone Marrow
The vertebral bodies contain bone marrow, which is responsible for producing blood cells and storing fat. The basivertebral veins play a role in draining venous blood from the bone marrow within the vertebral bodies. This function is critical for maintaining the health of the bone marrow and ensuring that deoxygenated blood is removed from this important tissue. By draining blood from the bone marrow, the basivertebral veins help support the metabolic activity of the bone marrow and ensure that it remains a healthy and functional part of the vertebrae.
Adaptability to Postural Changes
As the body changes position—whether through standing, sitting, bending, or lying down—there are shifts in pressure and blood flow within the vertebral column. The basivertebral veins are involved in adapting to these postural changes by facilitating venous drainage in response to changes in pressure within the vertebral bodies. This adaptability ensures that venous blood continues to flow smoothly from the vertebrae regardless of the body’s posture, preventing blood from pooling within the vertebrae and maintaining overall circulation in the spine.
Drainage of Adjacent Structures
In addition to draining blood from the vertebral bodies, the basivertebral veins may also provide venous drainage for nearby structures, such as the intervertebral discs and the annulus fibrosus, the outer portion of the discs. These structures, which are located between adjacent vertebral bodies, also rely on proper venous drainage to maintain their health and function. The basivertebral veins may receive small tributaries from these structures, ensuring that blood and waste products are efficiently removed from the surrounding tissues.
Venous Drainage Pathway in Disease and Trauma
In cases of vertebral body fractures or spinal trauma, the basivertebral veins play a crucial role in providing a pathway for venous blood to be drained from the injured vertebrae. The veins help maintain proper circulation and prevent the accumulation of blood within the vertebral bodies, which can occur due to injury. Similarly, in cases of diseases affecting the vertebrae, such as osteoporosis or tumors, the basivertebral veins help support venous drainage and ensure that the vertebrae remain functional even in the presence of pathological changes.
Clinical Significance
The basivertebral veins are clinically significant due to their involvement in conditions affecting the vertebral bodies, such as vertebral fractures, osteoporosis, and spinal tumors. In conditions like vertebral hemangiomas, these veins can become engorged, leading to pain and other complications. During spinal surgery, especially procedures like vertebroplasty or kyphoplasty, the basivertebral veins must be considered to prevent excessive bleeding or vascular injury.
The basivertebral veins are also pathways for the spread of metastatic cancer to the vertebrae, as the veins connect the vertebral bodies to the internal vertebral venous plexus, which has extensive communication with other venous systems in the body. Their role in vertebral venous drainage makes them critical for maintaining healthy circulation within the vertebrae, and any disruption to this system can lead to significant clinical issues such as venous congestion, pain, or neurological complications due to pressure on surrounding structures.
