A scan report can bring several unfamiliar words into the same conversation. A spinal disc is a cushion between neighboring vertebrae, the bones of the spine. Discs create space and allow movement. A herniated disc describes disc material pushing through a weakened area; it may press on nearby nerves. These descriptions concern structures, while the symptoms and examination help explain what those structures mean for a particular person. MedlinePlus explains disc structure.
Inside the disc
The disc has a firm, flexible outer ring, the annulus fibrosus, around a softer center, the nucleus pulposus. These names describe different parts of the same structure. The spinal cord runs through a protective canal formed by the vertebrae. Nerve roots branch from the cord and leave through openings in the spine. The guide to how joints and discs work follows that anatomy in more detail. OrthoInfo describes the disc.
As discs age, they may lose water and height and begin to bulge. Neighboring bones can then lie closer together, and additional bone growth may narrow the openings where nerves leave. The anatomy and the symptoms are separate parts of the assessment: OrthoInfo notes that worn discs and nerve compression can exist without painful symptoms. A description of wear therefore needs interpretation in the context of the person being examined. OrthoInfo describes age-related changes.
What researchers mean by degeneration
A 2006 review proposed a definition of disc degeneration that emphasizes structural failure together with changes involving disc cells; it reserved degenerative disc disease for a degenerate disc that is painful Read the review abstract.
That review identified inheritance, aging, the transport of nutrients and other substances, and the history of mechanical loading as contributing factors. Its account is more involved than a simple picture of a disc wearing away from ordinary use. A separate review describes the disc as a complex structure whose natural composition and mechanical properties make repair research challenging. Neither description identifies the cause of an individual reader’s pain. The review discusses contributing factors. The physiology review describes this complexity.
The disc’s complexity is also a reason to distinguish an explanation of tissue biology from an answer about treatment. A review of disc physiology describes substantial challenges arising from its composition, microscopic structure and mechanical behavior. Those are research observations about the tissue; interpreting a person’s symptoms requires the clinical assessment described below. Read the physiology review abstract.
A herniated disc and sciatica
A herniated disc is disc material extending through a weakened area of the disc. If a nearby nerve is affected, symptoms may include pain, numbness or weakness. In the lower back, pain may extend into the buttock or leg. In the neck, symptoms may extend toward the shoulder, arm or fingers. The location of the affected disc helps explain why the symptoms can be felt away from the spine itself. MedlinePlus describes herniation.
Sciatica concerns irritation or compression of the sciatic nerve, whose pathway runs from the lower back toward the feet. The NHS describes sharp or burning leg pain, tingling, numbness and weakness. A slipped disc is a possible cause, but narrowing within the spine and other spinal problems can also cause it. The word describes a pattern that needs an explanation rather than naming a particular implant or operation. The NHS explains symptoms and causes.
Spinal stenosis: the space around the nerves
Spinal stenosis means that spaces in the spine have narrowed. These can include the central spinal canal, which contains the cord and nerve roots, and the openings where nerves leave. NIAMS describes age-related changes, thickened supporting tissues, bone growth and a bulging disc among the ways space can become restricted. Stenosis commonly involves the lower back or neck, but the term describes narrowing rather than a single cause. NIAMS explains where narrowing occurs.
Symptoms depend on where the narrowing occurs. NIAMS lists lower-back or leg pain, tingling, cramping and weakness with lumbar stenosis; standing or walking may make symptoms more noticeable. In the neck, symptoms may extend into the arms and hands. Some people have no symptoms. This range is why the name on a report does not by itself describe someone’s daily limitations or determine a treatment plan. NIAMS describes the range of symptoms.
Spondylosis and radiculopathy in the neck
Cervical means the neck region. Cervical spondylosis describes age-related changes in its discs and joints. OrthoInfo describes disc-height loss, changes in joint cartilage and additional bone growth. Some people experience neck pain or stiffness, while others notice no symptoms. The term covers changes in the neck’s structures and does not automatically mean that a nerve has been affected. OrthoInfo explains cervical spondylosis.
Radiculopathy refers to a problem affecting a spinal nerve root. Cervical radiculopathy occurs when a nerve in the neck is irritated or compressed near where it branches from the cord. Pain may travel toward the shoulder or arm, with weakness or numbness. OrthoInfo describes both degenerative changes and a herniated disc as possible causes, making the nerve-related term different from the broader description of spondylosis. OrthoInfo describes the nerve problem.
How examination and imaging fit together
MedlinePlus describes a medical history and physical examination as the starting point for assessing a herniated disc. The clinician checks sensation, reflexes, strength, posture and movement. Imaging may include magnetic resonance imaging, or MRI, and computed tomography, or CT, to show the disc and surrounding spaces. A plain X-ray alone cannot establish a herniated-disc diagnosis. Questions about how a scan matches the examination belong in the conversation about the diagnosis. MedlinePlus explains the assessment.
Discography is a different test: the sciatica reference describes placing a needle into a disc to assess pressure, adding contrast material that shows on images, and noting whether the person’s pain is reproduced. This is a description of the test, rather than a reason to request it. The appointment and shared-decision guide offers general questions, while the comparison of fusion and disc replacement explains those operations separately. The sciatica reference describes discography.