Bulging and Slipped Disc Symptoms

Illustration of a spinal disc herniation between L4/L5 (4th and 5th lumbar vertebrae) and L5/S1 (5th lumbar and 1st sacrum)
BSIP/UIG/Universal Images Group/Getty Images

Bulging and slipped discs, while not exactly the same thing, are in the same family of spinal problems.  These injuries relate to the integrity of your spinal discs; the terms refer to the outward migration of the soft, jelly-like substance that is normally located in the center of the disc. In some cases, the nucleus, as this substance is called, even escapes the confines of the disc structure altogether.

The difference in terms is mainly a matter of degree. Sometimes a disc "blows out" all at once; other times, for example, in many cases of minor injury to the outside of the disc or of age-related and other degenerative spinal changes, the nucleus will remain intact inside the disc structure, but will have moved away from center.

In fact, doctors use terms to describe the stage or type of migration. The three main types are:

  • Prolapse, which is essentially a bulging disc. In this type, the nucleus can be viewed on an MRI as bulging out between the spinal bones directly above and below. But the outer most layers of the disc, which is made of several rings of tough fibers strong enough to hold the nucleus in remain intact.
  • Extrusion, where, due to a tear in the tough outer fibers (the structures mentioned above) some of the nucleus is able to escape, but it remains connected to the central part of the disc.
  • Sequestration, otherwise known as a herniated disc or, in layman's terms, a slipped disc, occurs when some or all of the nucleus not only escapes, but is disconnected from the disc, as well.

Bulging and slipped discs, as well as extruded discs, can occur in any of the three main regions of the spine.

In other words, these injuries occur in the neck, upper or mid-back and in the low back. They don't affect the sacral or coccyx regions because there are no intervertebral discs there.

Symptoms of Slipped Disc

By the way, the fact that you have one of these injuries does not automatically mean you'll have symptoms. But often you will. In the case of slipped disc (i.e., herniated disc,) symptoms usually come about when the dislodged disc tissue makes contact with a spinal nerve root.

The symptoms that are associated with slipped disc are called radiculopathy. In the low back, these symptoms are often referred to as sciatica, but sciatica is actually a more general term that does not describe how, exactly, the disc makes for pain and other issues. Radiculopathy symptoms include pain, numbness, weakness, and/or electrical sensations such as pins and needles, burning or shock, that go down just one leg or one arm (depending on the location of the injury.)

Most disc herniations occur in a "posteriolateral" direction, which is a combination of back and side; the movement you do when you sustain this type of injury will likely be the determining factor as to which side experiences the herniation, and therefore which limb gets the radiculopathy symptoms.

A herniated disc in the low back sometimes leads to pain, disturbance and/or numbness in the bowel or bladder, or it may cause your legs to get progressively weaker. These are symptoms of a very serious condition known as cauda equina syndrome. Cauda equina symptoms should be treated as a medical emergency. If you experience any of them, call your doctor or go to the emergency room immediately.


MD Consult. Herniated Intervertebral Disk. Elsivier. July 2010. http://www.mdconsult.com/das/pdxmd/body/215814010-2/1040215818?type=med&eid=9-u1.0-_1_mt_1014932&printing=true#Contributors

Michele C. Battié, PhD., et. al. The Twin Spine Study: Contributios to a changing view of disc degeneration. Spine Journal. Aug. 2009. http://www.thespinejournalonline.com/article/S1529-9430%2808%2901440-X/abstract

Slipped disk: Overview. PubMed Health. Oct. 2014. https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072656/