Spine & Orthopedic Glossary

Comprehensive Spine Glossary: Definitions of Key Spinal Terms and Conditions

As experienced spinal care providers, we understand how confusing medical terminology can be. That’s why we’ve created this comprehensive glossary of spinal terms, diagnoses, procedures, and anatomical references—to help you understand every step of your journey toward spine health. Whether you’re preparing for a consultation or researching your symptoms, this glossary is designed to clarify and empower.

Anatomical Structures of the Spine

Cervical Spine

The cervical spine is the uppermost section of the vertebral column, consisting of seven vertebrae (C1–C7). These vertebrae support the skull, enable head movement, and protect the spinal cord as it begins at the brainstem. C1 (atlas) and C2 (axis) are unique in allowing head rotation and nodding.

Thoracic Spine

Composed of 12 vertebrae (T1–T12), the thoracic spine connects to the rib cage and provides structural support and stability. It has limited range of motion compared to cervical and lumbar regions due to rib attachments.

Lumbar Spine

The lumbar spine contains five vertebrae (L1–L5) and bears the most weight of all spinal sections. It is the most common site of disc herniations and degenerative disorders due to mechanical stress.

Sacrum

The sacrum is a triangular bone formed by the fusion of five sacral vertebrae (S1–S5). It connects the spine to the pelvis and forms the sacroiliac joints.

Coccyx

Commonly known as the tailbone, the coccyx is made up of 3–5 fused vertebrae at the bottom of the spine. It plays a role in supporting sitting posture and muscle attachment.

Spinal Discs and Conditions

Intervertebral Disc

A fibrocartilaginous cushion between vertebrae that absorbs shock and allows for spinal flexibility. Each disc has a tough outer layer (annulus fibrosus) and a gelatinous core (nucleus pulposus).

Degenerative Disc Disease (DDD)

A condition where intervertebral discs lose hydration and elasticity, leading to reduced cushioning and pain. Common in aging individuals, especially in the lumbar spine.

Disc Herniation

Occurs when the nucleus pulposus pushes through a tear in the annulus fibrosus, often compressing nearby nerves. Symptoms may include pain, numbness, or weakness in the limbs.

Bulging Disc

Unlike a herniated disc, a bulging disc maintains its outer structure but protrudes beyond its normal boundary, which can press against nerves and cause discomfort.

Nerve-Related Terminology

Spinal Cord

The spinal cord is a long, cylindrical structure composed of nerve tissue that runs from the brainstem to the lower back. It transmits messages between the brain and body.

Nerve Root

The initial segment of a spinal nerve emerging from the spinal cord. Compression of a nerve root is a common source of radicular pain (e.g., sciatica).

Radiculopathy

Refers to pain, numbness, or weakness caused by nerve root irritation or compression. It often affects the cervical or lumbar spine and radiates into the arms or legs.

Myelopathy

Dysfunction of the spinal cord itself, commonly due to compression, often presenting with clumsiness, gait instability, or bowel/bladder issues.

Spinal Disorders

Scoliosis

A lateral curvature of the spine, often diagnosed in adolescence. Severe cases may require bracing or surgical correction.

Kyphosis

An exaggerated forward rounding of the thoracic spine, often giving a hunched appearance. Common in older adults due to vertebral compression fractures.

Lordosis

An excessive inward curve of the lumbar spine. May be congenital or related to poor posture, obesity, or muscular imbalance.

Spinal Stenosis

A narrowing of the spinal canal that causes pressure on the spinal cord or nerves. Most common in the lumbar and cervical spine, symptoms include pain, numbness, or weakness.

Diagnostic & Imaging Terms

MRI (Magnetic Resonance Imaging)

An advanced imaging method used to visualize soft tissues such as discs, nerves, and ligaments. MRI is often used to diagnose disc herniations, stenosis, and tumors.

CT Scan (Computed Tomography)

A radiographic imaging technique that creates cross-sectional views of the spine. Especially useful for evaluating bone detail and trauma.

X-ray

A standard imaging tool used to assess spinal alignment, bone integrity, and degenerative changes such as osteophytes.

Surgical and Non-Surgical Treatments

Laminectomy

A surgical procedure involving the removal of part of the vertebra (lamina) to relieve pressure on the spinal cord or nerves. Commonly used to treat stenosis.

Discectomy

Surgical removal of a portion of a herniated disc to alleviate nerve compression. Can be performed using open or minimally invasive techniques.

Spinal Fusion

A procedure that permanently joins two or more vertebrae to eliminate motion and provide stability, often used in cases of instability, spondylolisthesis, or after discectomy.

Microdiscectomy

A minimally invasive form of discectomy involving a small incision and use of a microscope. Typically performed on lumbar disc herniations.

Epidural Steroid Injection

A non-surgical treatment involving the injection of corticosteroids into the epidural space to reduce inflammation and alleviate pain.

Pain Syndromes

Sciatica

Radiating pain along the sciatic nerve, which extends from the lower back down the legs. Typically caused by lumbar disc herniation or spinal stenosis.

Facet Joint Syndrome

Pain originating from the small joints located between and behind adjacent vertebrae. Degeneration or arthritis in these joints can trigger inflammation and discomfort.

Piriformis Syndrome

A neuromuscular condition in which the piriformis muscle compresses the sciatic nerve, causing buttock and leg pain similar to sciatica.

Spinal Alignment and Stability Terms

Spondylosis

A general term describing age-related wear and tear affecting the spinal discs and joints. Often associated with osteoarthritis.

Spondylolisthesis

The forward displacement of one vertebra over another, often due to a stress fracture or degenerative changes. Can cause spinal instability and nerve compression.

Ankylosing Spondylitis

A chronic inflammatory disease leading to the fusion of spinal vertebrae, severely restricting mobility. It often begins in the sacroiliac joints.

Spine Care & Rehabilitation

Physical Therapy

A critical component of conservative spine care focused on strengthening, flexibility, posture correction, and pain relief. Helps restore function and prevent recurrence.

Orthopedic Spine Specialist

A medical doctor (MD or DO) specializing in diagnosing and treating disorders of the spine, often through surgical and non-surgical methods.

Don’t let back pain hold you back. At Big Apple Spine & Orthopedics, you’re in good hands for all your spine care needs. Schedule an Appointment Today with Big Apple Spine & Orthopedic!