Intervertebral discs lie between each vertebra in the spinal column and provide shock absorption for the spine. These “spongy” discs also prevent the bony vertebrae from rubbing against each other when the body moves.
Intervertebral discs possess a unique shock absorbing quality because they have a fibro-cartilaginous composition consisting of:
- The annulus fibrosus, or outer layer
- The nucleus pulposus, or inner layer
The outer layer of the discs is a tough material made of collagen fibers that anchor the disc to each vertebra. The nucleus pulposus inside is a jelly-like substance with a much higher concentration of water, and it is protected and contained by the annulus fibrosus. This soft inner layer allows the intevertebral disc to be “squished” and absorb energy, so that energy doesn’t transfer to the vertebrae and cause injury.
Thanks to their unique structure, intevertebral discs give the body its ability to flex and move without pain or discomfort. When these discs become damaged and their composition changes, this shock absorbing system fails, and pain and discomfort can result. Injured and/or damaged discs are commonly known as bulging discs, herniated discs, and degenerative discs, depending on the exact nature of the injury.
In the instance of a bulging disc, the intervertebral disc develops a protrusion that extends out beyond the disc’s normal place in the spinal column. Sometimes, a bulging disc does not cause symptoms because it is not impinging on the nerve roots in the spinal canal. However, when the bulge extends far enough, it can press on the nerve roots, causing symptoms such as radiating pain in the back, neck, legs, or arms, or numbness in the extremities. The bulge, or protrusion, of a bulging disc can be the result of a number of causes, including injury, age, or other disc damage.
If the bulging disc is located in the lumbar region (lower back area) of the spinal column, pain radiates to the hips, buttocks, legs, and feet. That’s because a bulging disc is pressing on spinal nerve roots that send movement and sensation signals to the lower extremities via peripheral nerves. When a bulging disc occurs in the upper back or neck (cervical) region, pain radiates down the arms and possibly to the fingers.
Ninety percent of bulging discs occur in the lower back. A lumbar bulging disc primarily occurs in one of two locations: at the L4-L5 segments of the spinal column or at lumbar segment 5 (L5) and sacral segment 1 (S1). Another low back problem known as sciatica occurs when a bulging disc is pressing on the sciatic nerve in the lower back. A cervical bulging disc would be located in the neck.
A bulging disc differs from a herniated disc in that the disc itself does not split open; it simply stretches. A herniated disc or ruptured disc, on the other hand, is an intervertebral disc in which the annulus fibrosus has split or become torn, causing the interior fluid to leak out.
For more information on bulging discs, and how Laser Spine Institute’s (LSI’s) gentle, minimally invasive procedures can treat them, contact us today for a free MRI or CT scan review.