A plain-English glossary

Conversations about backs and necks are full of specialist words. These short, plain definitions are meant to make those conversations easier to follow. They describe what the words mean, not what anyone should do; for that, talk with a health care provider.

Acute

Describes pain or an injury that comes on suddenly and is expected to pass. The opposite of chronic.

Annulus

The tough, fibrous outer ring of an intervertebral disc, which surrounds its softer centre.

Arthritis

A broad term for conditions affecting the joints. In the spine it is often used for wear-and-tear changes in the facet joints and discs.

Atlas and axis

The top two vertebrae of the neck. The atlas cradles the skull; the axis has a peg of bone that the atlas turns around.

Bursa and bursitis

A bursa is a small, fluid-filled sac that cushions moving parts near a joint. Bursitis is inflammation of a bursa.

Cartilage

Smooth, firm tissue that covers the ends of bones where they meet in a joint.

Cervical

To do with the neck. The cervical spine is the part of the spine in the neck.

Chiropractic

A licensed health care profession whose practitioners often use manual therapy, including spinal manipulation. See What chiropractic is.

Chronic

Describes pain or a condition that lasts a long time, or keeps coming back, beyond the time an injury would normally be expected to heal.

Coccyx

The small tailbone at the very bottom of the spine.

Contusion

The medical word for a bruise: an injury in which small blood vessels are damaged without the skin being broken.

Degeneration

In the spine, the gradual changes in discs and joints that come with age. Degenerative changes are very common and often cause no symptoms.

Disc (also spelled disk)

A cushion-like pad between two vertebrae, with a tough outer ring and a softer centre. See Discs and sciatica.

Ergonomics

The study of how work, tools and surroundings fit the people using them. The Occupational Safety and Health Administration describes it as fitting a job to a person.

Facet joints

Pairs of small joints at the back of the spine that link each vertebra to the ones above and below.

Foramen

An opening in or between bones. In the spine, nerve roots leave through openings between neighbouring vertebrae.

Herniated disc

A disc whose softer centre has pushed through a weak spot in the outer ring, sometimes pressing on nearby nerves. Popularly, if inaccurately, called a slipped disc.

Inflammation

The body's response to injury or irritation, which can bring redness, warmth, swelling and pain. It is part of the normal early stage of healing.

Intervertebral

Between the vertebrae.

Ligament

A tough band of tissue that joins one bone to another and steadies a joint.

Lumbar

To do with the lower back. The lumbar spine sits between the rib cage and the pelvis.

Manipulation

A technique in which a practitioner applies a controlled thrust to a joint. See Spinal manipulation explained.

Mobilization

Slower, gentler movement of a joint within its natural range, without a thrust.

Musculoskeletal

To do with the muscles, bones, joints and the tissues that connect them.

Nerve root

The part of a nerve where it branches off the spinal cord and leaves the spine.

Neutral position

A comfortable posture in which the joints are naturally aligned, a term used in workplace guidance.

Overuse injury

An injury that builds up gradually from repeating the same movement or load, such as tendinitis. Also called a chronic or repetitive injury.

Physical therapist

A licensed health professional who works with people who have injuries and conditions affecting movement, using exercise, movement and other hands-on methods. Also called a physiotherapist in many countries.

Radiating pain

Pain that spreads away from where it starts, for example from the lower back into a leg or from the neck into an arm.

Sacroiliac joints

The joints where the sacrum meets the two halves of the pelvis.

Sacrum

The triangular bone at the base of the spine, formed from vertebrae that fuse together.

Sciatica

Pain, numbness, tingling or weakness along the path of the sciatic nerve, from the lower back down the leg. It is a symptom rather than a diagnosis.

Spinal cord

The long bundle of nerves that runs down through the spine, carrying messages between the brain and the body.

Spinal stenosis

A narrowing of the spaces within the spine, which can put pressure on the spinal cord or nerve roots.

Spondylosis

A general term for age-related wear and tear of the spinal discs and joints. Cervical spondylosis refers to the neck.

Sprain

A stretched or torn ligament. See Sprains and strains.

Strain

A stretched or torn muscle or tendon.

Subluxation

In general medicine, a partial dislocation of a joint. Within chiropractic, the word is also used in a different sense to describe a problem with the alignment or movement of spinal joints.

Tendon and tendinitis

A tendon is a cord of tissue that connects muscle to bone. Tendinitis is inflammation or irritation of a tendon.

Thoracic

To do with the chest. The thoracic spine is the section of the spine where the ribs attach.

Vertebra (plural vertebrae)

One of the small bones stacked together to form the spine.

Whiplash

A neck injury caused by a sudden back-and-forth movement of the head, often in a vehicle collision.

Most of these definitions draw on the plain-language descriptions published by MedlinePlus and its partner institutes, such as the overview of sports injuries from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. For more detail on any term, the pages linked above explain it in context.