What is flatten ventral spinal cord displacing the thecal sac anteriorly?

Answer 1

Looking down on the involved levels (L5-S1), the top is toward your abdomen (NOON) and the back is toward the back (6 O'clock). I'll describe what happens, referring to times on the clock. Between each vertebra are thick disks: these comprise of a thick wall on the outside, filled with a thick gel. This acts as a "shock absorber". Nerves travel down the spinal canal as a thick cord of nerves and this cord is encased in a 3-layered sac, or envelope. Each nerve arises at a point in the brain, and travels down the cord, exits at its determined level and travels down the body to where it is designed to go/operate. Over the years these disks begin to wear out and flatten or possibly bulge out (like squashing a marshmallow). Sometimes, trauma --or bending or leaning with/without heavy lifting-- can cause a herniation in the side of this disk, and the resulting herniation can cause problems by pinching a nerve. If the herniation occurs at 5 o'clock or 7 o'clock, the herniation can pinch (trap) a nerve as it is preparing to leave the spinal cord and travel down the body, resulting in a severe burning pain and possibly muscle cramps if the nerve travels to the spasming muscle. If the herniation occurs at the NOON position, since no nerves (only blood vessels and bowel), there is no pain (actually, there can be pain, but it is not from nerves being pinched... there are pain fibers in the disk). If the herniation occurs at the 6 o'clock position no nerves will be trapped or pinched because there is a lot of space in the spinal canal where the spinal cord travels, but the sac surrounding the cord as it runs down the body CAN be indented. This is what the xray is describing, and there is nothing to worry about in this case...