Understanding diagnostic imaging reports and evaluation terminology may help patients with chronic back pain engage more meaningfully in their care. The terms below cover key anatomical structures, common diagnoses, and specialized procedures you may encounter. Because spine conditions vary widely, interpretation of these findings is always individual; our clinical team evaluates each patient’s imaging in the context of their full clinical picture.

Spine Anatomy Terms

Intervertebral Disc

The intervertebral disc is a cushion-like structure located between each vertebra in the spinal column. It acts as a shock absorber and allows for flexibility and movement. Each disc has two main components: a tough, fibrous outer ring called the annulus fibrosus and a soft, gel-like inner core called the nucleus pulposus. Discs may degenerate, bulge, or herniate over time, and these changes can be a contributing source of chronic back pain in some patients. Assessing disc health is central to diagnosing many spine conditions.

Annulus Fibrosus

The annulus fibrosus is the strong, outer ring of an intervertebral disc, composed of multiple layers of fibrous collagen tissue. Its primary role is to contain the nucleus pulposus and provide structural integrity to the disc, resisting compressive and torsional forces on the spine. Tears or fissures in the annulus fibrosus are a recognized contributing factor in discogenic pain and are often identified during diagnostic evaluation. When the annulus is disrupted, inflammatory substances from the nucleus may leak out and irritate nearby nerves, which can lead to persistent discomfort in some patients.

Nucleus Pulposus

The nucleus pulposus is the soft, gel-like center of a spinal disc, primarily composed of water and proteoglycans. Its composition allows it to function as a primary shock absorber, distributing pressure across vertebral bodies during movement. When the annulus fibrosus is compromised by a tear, the nucleus pulposus can sometimes push through, leading to a herniated disc. Diagnostic imaging often assesses the hydration and structural integrity of the nucleus pulposus, as changes may indicate degenerative disc disease and may be a contributing factor in some patients’ chronic back pain.

Vertebra

A vertebra is one of the individual bones that make up the spinal column. The human spine consists of 33 vertebrae, organized into cervical (neck), thoracic (mid-back), lumbar (lower back), sacral, and coccygeal regions. Diagnostic imaging — including X-rays, CT scans, and MRI — examines the vertebrae for alignment, fractures, bone spurs, and degenerative changes. These findings help our clinical team assess overall spinal health and identify potential contributing sources of discomfort.

Foramen (Neural Foramen)

The neural or intervertebral foramen is a natural opening on each side of the spinal column through which spinal nerves exit and extend to the rest of the body. Diagnostic imaging frequently evaluates the foraminal spaces to detect narrowing, known as foraminal stenosis. When these openings become constricted — due to disc bulging, herniation, bone spurs, or thickened ligaments — exiting nerves may be compressed, potentially producing symptoms such as pain, numbness, or weakness in the arms or legs.

Facet Joint

Facet joints are small, paired joints on the posterior side of each vertebra that connect adjacent vertebral segments. They guide and limit spinal movement, providing stability while permitting bending and twisting. Like other joints, facet joints can undergo degenerative changes — a condition called facet arthropathy — and may become a contributing source of chronic localized back pain in some patients, often distinct from disc-related pain. Diagnostic imaging helps identify inflammation or degeneration in these joints, informing management decisions.

Common Disc Conditions

Annular Tear

An annular tear is a fissure or rip in the annulus fibrosus, the tough outer ring of an intervertebral disc. These tears are a recognized, though sometimes overlooked, contributor to chronic low back pain. Some annular tears are asymptomatic, while others may allow inflammatory chemicals from the nucleus pulposus to leak out and irritate nearby spinal nerves, causing persistent discomfort. Because the disc has a limited blood supply, annular tears may not heal effectively on their own, making them a target for advanced diagnostic evaluation. A specialized procedure called an annulargram may be used to confirm their presence and assess whether they are the pain source. Learn more about annular tears and non-surgical treatment options.

Degenerative Disc Disease (DDD)

Degenerative Disc Disease (DDD) is not a disease in the traditional sense but rather a term describing progressive, age-related breakdown of one or more intervertebral discs. It is characterized by loss of disc height, reduced disc hydration, and the development of tears in the annulus fibrosus. These changes may lead to chronic back pain, stiffness, and nerve compression in some individuals, though disc degeneration is visible on imaging in many people over age 60 who have no symptoms. Diagnostic imaging plays an important role in identifying the extent and location of degenerative changes. For a broader overview, see our guide on lumbar spine conditions and regenerative disc repair.

Herniated Disc

A herniated disc occurs when the nucleus pulposus pushes through a tear in the annulus fibrosus and extends beyond its normal boundaries. This can result from trauma, repetitive loading, or ongoing degeneration. The displaced disc material may compress nearby spinal nerves, potentially producing pain, numbness, tingling, or weakness that radiates into an arm or leg — commonly described as radiculopathy or sciatica. MRI is often particularly effective for visualizing herniated discs and their relationship to surrounding neural structures. Read more in our resource on common lumbar spine conditions causing low back pain.

Bulging Disc

A bulging disc is a common imaging finding in which disc material extends beyond its normal boundary but remains contained within the outer annulus fibrosus. Unlike a herniated disc — where the nucleus has broken through the annulus — a bulging disc typically involves a broader, more circumferential outward extension. While a bulging disc may not cause symptoms in every case, it can contribute to pain by pressing on spinal nerves or narrowing the spinal canal, particularly when combined with other degenerative changes. Diagnostic imaging helps differentiate bulging from herniated discs and assess their potential clinical impact.

Symptom Terminology

Sciatica

Sciatica describes a pattern of symptoms — rather than a specific diagnosis — characterized by pain that radiates along the path of the sciatic nerve, the longest nerve in the body, which runs from the lower back through the buttock and down the back of each leg. In many patients, sciatica results from compression or irritation of the lumbar nerve roots that contribute to the sciatic nerve, most commonly due to a herniated disc, spinal stenosis, or bone spurs. Diagnostic evaluation aims to identify the underlying structural cause, combining physical examination with imaging to locate the source of nerve compression. Our article on myths about sciatica and non-surgical relief offers additional context.

Radiculopathy

Radiculopathy refers to pain, numbness, tingling, or weakness that travels along the distribution of a compressed or irritated nerve root as it exits the spinal column. Common causes include herniated discs, bulging discs, bone spurs, or spinal stenosis pressing on a nerve root. Depending on which spinal region is affected, radiculopathy may be described as cervical (affecting the neck and arms) or lumbar (affecting the lower back and legs, often overlapping with sciatica). MRI is frequently used to identify the specific nerve root involved.

Discogenic Pain

Discogenic pain is a type of chronic low back pain that originates directly from damage or degeneration within an intervertebral disc, rather than from nerve compression. It is typically felt deep in the back and may worsen with sitting, bending, or lifting. Discogenic pain is often associated with annular tears or internal disc disruption, leading to inflammation and sensitized pain signals within the disc itself. Because discogenic pain can be difficult to confirm through MRI alone, specialized diagnostic procedures such as an annulargram may be used to help determine whether a specific disc is the pain generator.

Spinal Stenosis

Spinal stenosis refers to narrowing of the spinal canal or nerve root passageways (foramina) within the spine. This narrowing may place pressure on the spinal cord and nerve roots, potentially leading to pain, numbness, tingling, or weakness in the back, legs, or arms in some patients. Common contributing causes include age-related degenerative disc changes, bulging discs, bone spurs, and thickened ligaments. MRI is particularly useful for visualizing the extent and location of the narrowing and helping guide management decisions. For more detail, see 10 common symptoms of spinal stenosis and 8 non-surgical treatments for spinal stenosis.

Diagnostic Procedures

Annulargram (Discogram)

An annulargram — also referred to as a discogram — is a specialized diagnostic procedure used to help determine whether a specific intervertebral disc is the source of a patient’s chronic back pain, particularly when discogenic pain or an annular tear is suspected. Under fluoroscopic (live X-ray) guidance, a thin needle is directed into the disc in question and a small amount of contrast dye is injected. If the injection reproduces the patient’s characteristic pain pattern and the dye distribution reveals structural abnormalities such as an annular tear, this information may help confirm that disc as the pain generator. Annulargram findings are often used as part of the evaluation process for patients being considered for biologic disc repair or intra-annular fibrin injection. Outcomes of any subsequent treatment vary by individual case; candidates are evaluated thoroughly before a treatment path is recommended.

Expert Take

Diagnostic imaging provides a structural snapshot, but it rarely tells the full story on its own. In our clinical experience, the most meaningful evaluations combine advanced imaging with a thorough history, physical examination, and — where appropriate — provocative diagnostic procedures such as an annulargram. A finding on MRI only becomes clinically relevant when it correlates with a patient’s reported symptoms and functional limitations. This individualized approach is essential to identifying who may benefit from targeted interventions like biologic disc repair or annular tear repair, and who may be better served by other management strategies.

For a broader reference on spine terminology, visit our comprehensive glossary of spine health and treatment terms. If you are exploring non-surgical approaches to disc pain, our overview of 5 non-surgical disc treatments for chronic back pain may also be helpful.