Lumbar Herniated Disc
A herniated disc is an intervertebral disc that has become damaged due to loss of fluid volume in its interior (nucleus pulposus) and a due to a tear in its outer envelope (annulus fibrosus). This outer envelop, or annulus fibrosus is composed of overlapping rings of tough ligament fibers with enough strength to resist being torn when weight and pressures compress the spine. Yet this fibrous structure of rings are permeable enough to allow water and nutrients to be absorbed into its center, through blood vessels outside the disc. When this overall structure is healthy, the outer covering of the disc remains intact, and its nucleus is capable of absorption of fluids and nutrients at an equal rate than it would leave the disc.
As we get older, these intervertebral discs may undergo degenerative changes, beginning on the inside or outside, or simultaneously. In one scenario, the rate in which this jelly-like interior is able to absorb water and nutrients is slower than the rate at which these same materials leave the disc. In another scenario, the walls of the disc may become torn or ruptures due to old age or traumatic injury. Either of these two degenerative changes to the disc can accelerate disc degeneration.
When the outer wall of the annulus does become torn, the condition is known as a herniated disc. Other terms used to describe this same condition include "bulging disc", "disc disease", "disc protrusion", and "pinched nerve". Some doctors are reluctant to use the term pinched nerve because the jelly-like material expelled through the wall of the disc during a herniation may not come in contact with the adjacent nerve root of the spine. It is generally understood today that back pain symptoms related to herniated discs only occur when this expelled material comes in contact with the adjacent nerve root and compresses it directly
A herniated disc may directly or indirectly cause back pain or lumbar back pain. One direct cause of pain with this process is when the materials ejected press into the adjacent nerve root. When this occurs, the person may experience pain-like symptoms in that area of the spine, and at any location along the path of that nerve. When this process occurs in the discs between the lumbar vertebrae, the condition is known as a lumbar herniated disc. Often patients with lumbar herniated discs experience pain in their lower backs as well as other changes in nerve sensations down their leg is because the nerve roots at the bottom of the lumbar segments travel down the leg. Often, doctors can know which lumbar herniated disc is involved with the patient's lower back pain by the location of their symptoms. For example, research in neurology and human anatomy has shown us that the nerve roots which give us our ability to feel our feet and toes, and to flex and extend them, are located at the levels of L4, L5, and S1. Patients with herniated discs in this area may feel numbness, burning, and weakness in their foot, to the point where they may not be able to extend it to push off with when they walk. This condition is known as foot drop.