Intervertebral foramina (side view)Thirty-one pairs of nerve roots emerge from the spinal cord through these spaces. At
each vertebral level of the spine there are two nerve roots.
Pain, numbness, weakness, and tingling are symptoms that may develop when one or
more spinal nerves are injured, irritated, or stretched. The back pain that you and I have
is because of pressure or irritation of these nerves. A degenerated disc, slipping of one
vertebra over another, narrowing of the spinal canal, erosion of the spongy cartilage in
the facet joints – all of these squeeze, rub or stretch the nerve roots causing electrical
impulses to be sent to the brain that is translated as pain.
Summary
What we have learnt so far is that the backbone is composed of a number of bony blocks
called vertebrae. These vertebrae are stacked one above the other and held in place by
strong fibrous connective tissues called ligaments. Between the vertebrae, there are soft
jelly-like cushions called intervertebral discs that act as shock absorbers and help in the
smooth mobility of the spine in all directions.