Anatomy of the vertebral canal

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Figure 1. Cut section of the spinal cord
Figure 2. Cauda equina and filum terminale. A. Posterior view of spinal cord with cut lamina. B. Cauda equina removed.
Figure 3. Posterior view of spinal cord with exploded meninges.
Figure 4. Axial view of spinal cord showing dura and associated structures.
Figure 5. Axial view of spinal cord showing arachnoid mater and trabeculae.
Figure 6. Posterior view of spinal cord.
Figure 7. Posterior view of spine with cut lamina.  
Figure 8. Blood supply of the spinal cord. A. Posterior view of spinal cord.  B. Zoomed in view of anterior spinal cord.
Figure 9. Axial view of vertebrae showing venous drainage of the spinal cord


When they say to watch your back, you really should, because there is something pretty important in there called the spinal cord. Now, if you think of a nerve as a road, then the spinal cord is a huge highway.

It’s a major reflex center and holds many neural tracts that connect the brain to the rest of the body, allowing for important communication to occur.

The spinal cord starts at the foramen magnum, where it is continuous with the medulla oblongata, which is the most caudal portion of the brainstem.

It then extends inferiorly through the vertebral canal. In adults, it usually ends at the level of the first or second lumbar vertebra.

In infants, it usually ends at the second or third lumbar vertebra. The tapered end of the spinal cord is called the conus medullaris.

If we look at a transverse section of the spinal cord, we can see the anterior median fissure that extends along the midline of the spinal cord, anteriorly. Similarly, the posterior median sulcus extends along the midline of the spinal cord, posteriorly.

The spinal cord can be divided into spinal cord segments. One spinal cord segment gives rise to the anterior and the posterior nerve roots, which come together to form a spinal nerve on each side of the spinal cord.

There are 31 spinal cord segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. A spinal nerve pair shares its name with the spinal cord segment it arises from.


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