Vertebral Column Arteries, Veins, and Innervation Explained

Overview

In this Osmosis lecture from Elsevier, the vertebral column's blood supply, venous drainage, and innervation are explained with a focus on the anatomical organization around the vertebrae, spinal cord, and surrounding ligaments.

• Arterial branches include periosteal, equatorial, and spinal branches feeding vertebrae and their coverings
• Spinal branches form anterior and posterior canal branches supplying the vertebral canal
• Vertebral venous drainage occurs via internal and external plexuses and basivertebral veins
• Recurrent meningeal nerves innervate the vertebral column, with facet joints supplied by articular branches

Introduction

The video provides a comprehensive look at how the vertebral column is nourished and innervated. It outlines the arterial sources that feed the vertebrae, the venous drainage pathways that ensure venous return, and the neural innervation that supplies bone, ligaments, and joints along the spine. The explanation ties together regional differences in arteries with the universal pattern of vertebral canal innervation, highlighting how vascular and neural structures interact with the vertebral bodies, arches, ligaments, and intervertebral discs.

Arterial Supply to the Vertebrae

The arteries supplying the vertebral column originate from several larger parent vessels, with regional variation by vertebral level. In the neck, parent arteries include the vertebral and ascending cervical arteries. In the thorax, the posterior intercostal arteries contribute. In the abdomen, the subcostal and lumbar arteries play a role, and in the pelvis, the iliolumbar, lateral sacral, sacral and median sacral arteries participate. As these parent arteries traverse the external surfaces of the vertebrae, they give rise to periosteal branches that feed the periosteum, equatorial branches that feed the vertebral bodies, and spinal branches that pass through intervertebral foramina and divide into anterior and posterior canal branches. Anterior canal branches lie along the vertebral body surface within the canal and give nutrient branches to the red marrow. Posterior canal branches run along the vertebral arch and terminate as radicular arteries for nerve roots and segmental medullary arteries for the spinal cord. These canal branches also give rise to ascending and descending branches that anastomose with spinal canal branches at adjacent levels.

Venous Drainage of the Vertebral Column

Venous blood from the vertebral column is drained by spinal veins that form internal (epidural) and external vertebral venous plexuses. The internal plexus lies within the vertebral canal, while the external plexus is outside the canal; they communicate through intervertebral foramina. The internal plexus is subdivided into anterior and posterior components and may form large longitudinal sinuses. Basivertebral veins drain the vertebral bodies and feed into both the anterior internal and anterior external vertebral venous plexuses. Intervertebral veins receive blood from the spinal cord and plexuses and exit through the intervertebral foramina to drain into the vertebral veins in the neck and the segmental veins in the trunk.

Innervation of the Vertebral Column

The vertebral column is innervated by small meningeal or recurrent meningeal branches that arise from mixed spinal nerves as they exit the intervertebral foramen. The facet joints are an exception, receiving innervation from articular branches that arise from the medial branches of the posterior rami of spinal nerves. The recurrent meningeal nerves traverse into the vertebral canal and supply structures such as the periosteum, ligamenta flava, posterior longitudinal ligament, spinal dura mater, and blood vessels, as well as the posterolateral aspects of the annulus fibrosus. Branches that remain outside the canal provide innervation to the anterolateral aspects of the vertebral bodies, their periosteum, the annulus fibrosus, and the anterior longitudinal ligament. This arrangement explains the widespread innervation of vertebral and adjacent structures by a relatively small set of nerve branches arriving from mixed spinal nerves before they separate into anterior and posterior rami.

Recap

To summarize, the vertebral column receives arterial supply from periosteal, equatorial, and spinal branches emanating from cervical and segmental arteries, with regional variation along the column. Venous drainage occurs through internal and external vertebral venous plexuses and basivertebral veins, with intervertebral veins completing the circuit to neck and trunk venous systems. The majority of vertebral innervation is via recurrent meningeal nerves, while facet joints have distinct innervation from medial branches of the posterior rami. This vascular and neural network supports protection, structure, flexibility, and motion of the spine, underlining the intricate integration of bones, ligaments, and nerves that maintain spinal health.