Spine Conditions Glossary
Definitions of medical terms related to the spine: anatomy, conditions, surgical procedures and clinical investigations.
A
Annulus fibrosus
The tough outer ring of the intervertebral disc, made of concentric layers of collagen fibres. A tear in the annulus allows the nucleus pulposus to protrude, forming a disc herniation.
C
Cervical myelopathy
Dysfunction of the cervical spinal cord caused by chronic compression from arthritis. Symptoms include gait disturbance, hand clumsiness and urinary problems. It is considered a relative surgical emergency.
See: Cervical Myelopathy →Cervicobrachial neuralgia
Pain originating in the neck and radiating into the shoulder, arm and sometimes the hand, caused by compression of a cervical nerve root. Often described as the "sciatica of the arm".
See: Cervicobrachial Neuralgia →Coccyx
A small triangular bone at the very bottom of the spine, formed by the fusion of 3 to 5 rudimentary vertebrae. Coccyx pain (coccydynia) is most commonly caused by a fall or direct trauma.
Cruralgia
Pain along the course of the femoral nerve, radiating into the front of the thigh. Usually caused by a high lumbar disc herniation (L3-L4).
See: Lumbar Disc Herniation →CT scan (computed tomography)
A medical imaging technique using X-rays to produce cross-sectional images of the body. Excellent for visualising bony spinal structures, fractures and calcifications.
D
Decompression
A group of surgical techniques aimed at relieving pressure on compressed neural structures (spinal cord, nerve roots). Includes laminectomy, foraminotomy and discectomy.
Disc degeneration (degenerative disc disease)
Progressive wear of the intervertebral disc involving loss of height, dehydration and fissuring. A natural ageing process that can become symptomatic, causing chronic low back pain.
See: Low Back Pain & Disc Disease →Disc herniation
Abnormal protrusion of the nucleus pulposus of an intervertebral disc through a tear in the annulus fibrosus. It can compress a nerve root (sciatica, cruralgia) or the spinal cord (myelopathy).
See: Lumbar Disc Herniation →Disc protrusion
Bulging of the intervertebral disc beyond its normal boundaries without complete rupture of the annulus fibrosus. A stage preceding true disc herniation, often asymptomatic.
Disc replacement (artificial disc)
An articulated implant that replaces a degenerated intervertebral disc while preserving motion of the operated segment. An alternative to spinal fusion, primarily used in the cervical spine.
Discectomy
Surgical removal of part or all of a herniated intervertebral disc to decompress the nerve root. Performed under microscope or endoscopy, it is the most common procedure for disc herniations.
See: Lumbar Disc Herniation →E
EMG (electromyography)
A neurophysiological test measuring the electrical activity of muscles and nerve conduction. Used to assess nerve root damage (radiculopathy) and to determine its level.
F
Facet joint (zygapophyseal joint)
A small paired joint located at the back of each vertebra, providing stability and guiding spinal movement. Facet joint arthritis is a common cause of low back pain.
Foramen (intervertebral foramen)
A bony opening on each side between two adjacent vertebrae through which the spinal nerve root exits the spinal canal. Its narrowing (foraminal stenosis) can compress the nerve and cause radiculopathy.
Foraminotomy
A surgical procedure that widens the intervertebral foramen to decompress a nerve root. Often performed in the cervical spine to treat cervicobrachial neuralgia.
See: Cervicobrachial Neuralgia →I
Intervertebral disc
A fibrocartilaginous cushion between two vertebrae, composed of a gelatinous central nucleus pulposus and a peripheral annulus fibrosus. It absorbs shock and allows spinal mobility.
K
Kyphoplasty
A variant of vertebroplasty in which a balloon is first inflated inside the fractured vertebra to restore its height before cement injection. Partially corrects the kyphotic deformity.
See: Vertebral Fractures →L
Laminectomy
Surgical removal of part of the vertebral lamina (posterior arch) to widen the spinal canal and decompress neural structures. The standard procedure for lumbar spinal stenosis.
See: Lumbar Spinal Stenosis →Lasègue sign (straight leg raise test)
A clinical test in which the examiner raises the patient's extended leg while lying flat. Reproduction of radiating leg pain (sciatica) before 60° constitutes a positive Lasègue sign.
Ligamentum flavum (yellow ligament)
An elastic ligament connecting adjacent vertebral laminae at the back of the spinal canal. Its thickening with age contributes to spinal canal narrowing (stenosis).
Low back pain (lumbalgia)
Pain localised in the lower back (lumbar region) without radiation into the legs. Termed acute (lumbago) if lasting less than 6 weeks, and chronic if persisting beyond 3 months.
See: Low Back Pain & Disc Disease →M
MRI (magnetic resonance imaging)
A medical imaging technique using a powerful magnetic field to visualise soft tissues (discs, spinal cord, nerves) with superior detail compared to CT. The gold standard for diagnosing spinal conditions.
N
Neurogenic claudication
Pain or weakness in the legs that appears during walking and is relieved by rest or leaning forward. A hallmark symptom of lumbar spinal stenosis, to be distinguished from vascular claudication.
See: Lumbar Spinal Stenosis →Nucleus pulposus
The gelatinous central part of the intervertebral disc, rich in water and proteoglycans. Its extrusion through the annulus fibrosus constitutes a disc herniation.
O
Osteophyte (bone spur)
A bony outgrowth developing at the margin of an arthritic joint or vertebral endplate. Osteophytes can contribute to narrowing of the spinal canal or foramina.
Osteosynthesis (spinal instrumentation)
Surgical fixation of spinal segments using pedicle screws, rods and/or metal plates. Used to stabilise vertebral fractures or as part of a spinal fusion procedure.
See: Spinal Trauma →P
Pedicle screw
A specialised screw inserted through the pedicle of a vertebra to anchor rods for spinal fixation. Used in spinal fusion and fracture stabilisation procedures.
R
Radiculopathy
Damage to a spinal nerve root causing pain, sensory loss or motor weakness in the territory supplied by that nerve. Sciatica and cruralgia are common radiculopathies.
S
Sacrum
A triangular bone formed by the fusion of 5 sacral vertebrae, located at the base of the spine between the two pelvic bones. It transmits the weight of the trunk to the lower limbs.
Sciatica
Pain following the course of the sciatic nerve, radiating from the buttock down the leg to the foot. Most commonly caused by a lumbar disc herniation compressing the L5 or S1 nerve root.
See: Lumbar Disc Herniation →Spinal canal
The bony tunnel formed by the stacked vertebrae, housing the spinal cord and nerve roots. Its narrowing (stenosis) can compress these neural structures.
See: Lumbar Spinal Stenosis →Spinal cord
The main nervous tract contained within the spinal canal, extending from the brainstem to the first or second lumbar vertebra. It transmits motor and sensory signals between the brain and the body.
Spinal fusion (arthrodesis)
A surgical procedure that joins two or more adjacent vertebrae using bone grafts and/or instrumentation (screws, rods, cages). The goal is to eliminate painful or unstable motion between the affected vertebrae.
See: Spondylolisthesis →Spinal nerve
A mixed nerve (motor and sensory) arising from the spinal cord and exiting through the intervertebral foramen. Each spinal nerve supplies a specific skin area (dermatome) and muscle group.
Spinal stenosis
Narrowing of the spinal canal or intervertebral foramina, compressing neural structures. Can be congenital or acquired (arthritis, ligament thickening).
See: Lumbar Spinal Stenosis →Spondylolisthesis
Forward slippage of one vertebra over the one below it. May be degenerative (facet joint arthritis) or isthmic (stress fracture of the pars interarticularis). A source of low back pain and sometimes nerve compression.
See: Spondylolisthesis →V
Vertebra
A bone forming part of the spinal column, composed of a vertebral body (front) and a posterior arch enclosing the spinal canal. The spine has 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused) and 3–5 coccygeal vertebrae.
Vertebral compression fracture
A fracture in which a vertebral body collapses, most often from osteoporosis in older adults. Causes acute pain and progressive kyphosis (forward curvature).
See: Vertebral Fractures →Vertebroplasty
A minimally invasive procedure involving percutaneous injection of bone cement (PMMA) into a fractured vertebral body under imaging guidance. Provides rapid pain relief and fracture stabilisation.
See: Vertebral Fractures →