Spinal surgery terminology can be difficult to navigate, especially when facing a diagnosis that may involve surgical options. This glossary defines key terms related to spinal anatomy, common conditions, and surgical procedures in plain language. Understanding these terms may help patients have more informed conversations with their providers and evaluate both surgical and non-surgical pathways — outcomes and candidacy vary by individual.

Vertebra

A vertebra is one of the 33 individual bones that stack together to form the spinal column, which protects the spinal cord. These bones are grouped into regions: cervical (neck), thoracic (mid-back), lumbar (lower back), sacrum, and coccyx. Each vertebra has a body, an arch, and bony projections that serve as attachment points for muscles and ligaments. Knowing which vertebrae are involved in your condition — for example, L4-L5 or C5-C6 — helps pinpoint the location of pain or nerve compression and guides individualized treatment decisions.

Intervertebral Disc

An intervertebral disc is a cushion-like structure located between each pair of vertebrae. It acts as a shock absorber and allows the spine to flex and rotate. Each disc has a tough outer ring called the annulus fibrosus and a soft, gel-like center called the nucleus pulposus. Damage to an intervertebral disc — such as degeneration, bulging, or herniation — is a common source of back and neck pain. When conservative measures are insufficient for some patients, surgical options may be explored; candidacy is evaluated individually.

Annulus Fibrosus

The annulus fibrosus is the strong, multi-layered outer ring of an intervertebral disc, made up of concentric bands of collagen fibers. Its primary role is to contain the nucleus pulposus and to withstand the compressive and rotational forces placed on the spine. Tears or fissures in the annulus fibrosus are a frequent source of chronic back pain, as they can allow inflammatory material from the nucleus to escape and irritate nearby spinal nerves. In many patients, annular tears are a root cause of back pain that may respond to targeted repair approaches.

Nucleus Pulposus

The nucleus pulposus is the soft, gel-like center of an intervertebral disc. Rich in water content, it gives the disc its shock-absorbing properties and allows the vertebrae above and below to articulate smoothly. When the annulus fibrosus tears, the nucleus pulposus can extrude through the opening — a process called herniation — pressing on spinal nerves and producing pain, numbness, or weakness in the limbs. Understanding this structure helps clarify the rationale behind treatments aimed at either containing or removing displaced disc material.

Foramen

A foramen (plural: foramina) is a natural opening in the spine through which spinal nerve roots exit the spinal canal and travel toward the arms or legs. There is a foramen at each spinal level on both sides of the vertebral column. When a disc bulges, herniates, or bone spurs develop due to degeneration, these openings can narrow and compress the exiting nerve root — a condition called foraminal stenosis. The resulting nerve irritation, or radiculopathy, can cause pain, numbness, or weakness, sometimes prompting evaluation for surgical decompression or non-surgical alternatives.

Facet Joint

Facet joints are small, paired joints located at the rear of each vertebra. They connect adjacent vertebrae, guide spinal movement, and contribute to stability. These joints are lined with cartilage and enclosed by a synovial joint capsule. Over time, facet joints may develop arthritis — known as facet arthropathy — which can become a significant source of localized back or neck pain, particularly with twisting or extending the spine. Facet-related pain is distinct from disc-related conditions and may require its own targeted treatment considerations.

Degenerative Disc Disease (DDD)

Degenerative Disc Disease (DDD) describes the natural breakdown and wear-and-tear of intervertebral discs over time. Despite its name, it is better understood as a condition associated with aging rather than a classic disease process. DDD involves discs losing hydration, height, and elasticity, which can lead to annular tears, disc bulging, or herniation. Many people with disc degeneration experience no significant pain, while others develop chronic symptoms. For some patients, DDD may progress to nerve compression or spinal instability that warrants surgical evaluation when non-surgical methods have not provided adequate relief. Learn more about when conservative care for DDD stops working.

Herniated Disc

A herniated disc occurs when the soft nucleus pulposus pushes through a tear in the annulus fibrosus and extends beyond the disc’s normal boundaries. This displaced material can press on nearby spinal nerves or the spinal cord, producing sharp pain, numbness, tingling, or weakness in the arms or legs — a pattern known as radiculopathy or sciatica. Also called a ruptured or slipped disc, herniation is a common reason patients seek care. Treatment options range from conservative therapies to, in some cases, surgical procedures such as discectomy; individual evaluation determines the most appropriate path.

Spinal Stenosis

Spinal stenosis is a narrowing of the spinal canal or the nerve root passageways (foramina), which can put pressure on the spinal cord and nerve roots. It is most often caused by age-related degeneration — including bulging discs, thickened ligaments, and bone spurs (osteophytes) from arthritis. Symptoms may include pain, numbness, tingling, or weakness in the legs, particularly with standing or walking, and are often relieved by sitting or leaning forward. For patients whose symptoms remain severe despite conservative care, surgical procedures such as laminectomy may be considered. For an overview of what to look for, see 10 common symptoms of spinal stenosis.

Sciatica

Sciatica refers to pain that travels along the path of the sciatic nerve — from the lower back through the hips and buttocks and down one leg. It is not a condition in itself but a symptom of an underlying problem, most often a herniated disc, bone spur, or spinal stenosis compressing a sciatic nerve root in the lumbar spine. Sciatica may present as shooting pain, numbness, tingling, or muscle weakness and typically affects only one side of the body. Treatment options vary widely; many patients explore both conservative and interventional approaches. For a balanced perspective, see 10 myths about sciatica and non-surgical relief.

Radiculopathy

Radiculopathy describes symptoms caused by compression or irritation of a spinal nerve root as it exits the spinal canal. The location of involvement determines where symptoms appear: cervical radiculopathy affects the neck and arms, while lumbar radiculopathy affects the lower back and legs. Common causes include herniated discs, bone spurs, and spinal stenosis. Symptoms may include pain, numbness, tingling, or weakness that radiates along a specific nerve’s distribution. Identifying radiculopathy helps guide evaluation for treatments aimed at decompressing the affected nerve root, ranging from non-surgical interventions to surgery depending on the individual case.

Spinal Fusion

Spinal fusion is a surgical procedure that permanently connects two or more vertebrae, eliminating movement between them. The goals may include stabilizing the spine, correcting a deformity, or reducing pain caused by motion that aggravates nerves or damaged discs. During the procedure, bone graft material encourages the vertebrae to grow together over several months, typically reinforced with screws, rods, or plates. Fusion is generally considered for conditions such as severe spinal stenosis, scoliosis, spondylolisthesis, or unstable fractures when non-surgical treatments have not provided sufficient relief. Patients are evaluated individually to determine whether fusion is appropriate for their specific anatomy and goals. For those weighing their options, 5 signs you should get a second opinion before spinal fusion offers useful guidance.

Expert Take

Our clinical team notes that spinal fusion addresses instability effectively in appropriately selected patients, but it does not repair the underlying disc biology and may alter load distribution at adjacent levels. For some patients, exploring disc-preserving or biologic options before committing to fusion may be worthwhile; candidacy for any approach is assessed on an individual basis.

Discectomy

Discectomy is a surgical procedure that removes all or part of a herniated intervertebral disc pressing on a spinal nerve or the spinal cord. It is among the more common surgeries performed for disc herniation, particularly when patients experience persistent pain, numbness, or weakness that has not responded to conservative treatments. The procedure aims to relieve nerve compression and reduce symptoms. Because discectomy removes disc tissue rather than repairing it, some patients may experience altered spinal biomechanics or further degeneration over time. Minimally invasive techniques are frequently used to reduce recovery burden.

Laminectomy

A laminectomy is a surgical procedure that removes part of the vertebral bone called the lamina — the posterior portion of the vertebra that forms the roof of the spinal canal. By removing the lamina, the surgeon creates more space within the canal and relieves pressure on the spinal cord or nerve roots. Laminectomy is most commonly performed for spinal stenosis caused by bone spurs, thickened ligaments, or disc bulging. The procedure may help reduce pain and improve neurological function in appropriately selected patients; outcomes vary based on the extent and location of compression.

Failed Back Surgery Syndrome (FBSS)

Failed Back Surgery Syndrome (FBSS), also called post-laminectomy syndrome, refers to chronic back and/or leg pain that persists or recurs after one or more spine surgeries. It is a complex condition that may arise from factors including incomplete nerve decompression, scar tissue formation, nerve injury, or new problems at spinal levels adjacent to a prior surgery. Patients with FBSS often experience ongoing, debilitating pain that is difficult to manage. Non-surgical and regenerative approaches may be evaluated as options for some patients in this situation; individual assessment is essential to determine what, if any, additional treatment may help. For more context, see 5 things to know about avoiding failed back surgery by exploring regenerative disc repair first.

For a broader reference on spine anatomy and disc condition terminology, visit our companion resource: A Glossary of Key Terms in Spine Anatomy and Disc Condition Terminology.