A herniated disc is often referred to as a slipped disc, however the disc doesn’t actually slip out of place. Rather, the term herniation means that the material at the center of the disc has squeezed out of its normal space.
Herniation occurs when the nucleus in the center of the disc pushes out of its normal space. The nucleus presses against the annulus, causing the disc to bulge outward. Sometimes the nucleus herniates completely through the annulus and squeezes out of the disc.
Although daily activities may cause the nucleus to press against the annulus, the body is normally able to withstand this pressure. However, as the annulus ages, it tends to crack and tear. It is repaired with scar tissue. This process is known as degeneration. Over time, the annulus weakens, and the nucleus may begin to herniate (squeeze) through the damaged annulus. At first, the pressure bulges the annulus outward. Eventually, the nucleus may herniate completely through the outer ring of the disc.
Vigorous, repetitive bending, twisting, and lifting at work can place abnormal pressure on the shock-absorbing nucleus of the disc. If great enough, this increased pressure can injure the annulus, leading to herniation.
A lumbar disc can also become herniated during an acute (sudden) injury on the job. Lifting with the trunk bent forward and twisted can cause a disc herniation. A disc can also herniate from a heavy impact on the spine, such as falling from a ladder and landing in a sitting position.
Herniation causes pain from a variety of sources. It can cause mechanical pain. This is pain that comes from the parts of the spine that move during activity, such as the discs and ligaments. Pain from inflammation occurs when the nucleus squeezes through the annulus. The nucleus normally does not come in contact with the body’s blood supply. However, a tear in the annulus puts the nucleus at risk for contacting this blood supply. When the nucleus herniates into the torn annulus, the nucleus and blood supply meet, causing a reaction of the chemicals inside the nucleus. This produces inflammation and pain. A disc herniation may also put pressure against a spinal nerve. Pressure on an irritated or damaged nerve can produce pain that radiates along the nerve. This is called neurogenic pain.
McCormick Law Office attorneys in Milwaukee, Wisconsin carefully review radiology studies including MRI, CT scans, x-rays and discography to confirm objective evidence of disc herniation consistent with the subjective clinical findings of the doctor and surgeon. MRI findings are the best and most trustworthy evidence of a herniated disc from a work injury or aggressive job duties over time.