A Glossary of Orthopaedic Terms

If you have seen an orthopaedic specialist or had an injury involving bones, joints or muscles, you have probably met a lot of unfamiliar language. From ACL to arthroscopy, orthopaedic terminology can feel like a separate dialect. Understanding these terms helps you weigh up your options, make informed decisions and take an active part in your care.

This glossary covers the terms you are most likely to encounter.

Anterior cruciate ligament (ACL)

A ligament in the centre of the knee that controls rotation and forward movement of the tibia (shin bone). It is an important stabiliser of the knee, and is often injured in sports involving sudden stops or changes of direction.

Arthritis

Inflammation of a joint, often with pain, swelling and sometimes structural change. The most common forms are osteoarthritis, related to changes in joint cartilage over time, and rheumatoid arthritis, an autoimmune condition affecting the joint lining.

Arthrogram

An imaging study in which contrast fluid is injected into a joint to make internal structures more visible, which can help identify tears or other changes.

Arthroscopy

A minimally invasive procedure in which a small lighted camera, an arthroscope, is inserted into a joint through a small incision. It allows the surgeon to see inside the joint and, where appropriate, carry out repairs. Commonly used in the knee, shoulder and hip.

Bursa

A small fluid-filled sac that cushions between bones and nearby tendons or muscles around a joint.

Bursitis

Inflammation of a bursa, often related to repeated load, overuse or, less commonly, infection. It is common in the shoulder, elbow and hip.

Carpal tunnel syndrome

Compression of the median nerve as it passes through the carpal tunnel in the wrist. Symptoms can include numbness, tingling and weakness in the hand, particularly the thumb and middle fingers.

Cartilage

Smooth, flexible tissue covering the ends of bones within a joint, allowing movement with low friction. In arthritis, cartilage can wear down, contributing to pain and stiffness.

Fracture

A break or crack in a bone, ranging from a hairline crack to a complete break. Treatment depends on the fracture, and may involve immobilisation or surgery.

Ganglion cyst

A non-cancerous, fluid-filled lump that commonly forms on the wrist or hand. Often harmless, though it can cause discomfort or limit movement.

Gout

A painful condition caused by a build-up of uric acid crystals in a joint, most commonly the big toe. It is managed with medication and dietary changes.

Menisci

Two crescent-shaped discs of cartilage in the knee that act as shock absorbers. Meniscal tears are common and can cause pain, swelling and difficulty moving the knee.

Osteoarthritis

The most common type of arthritis, involving changes to joint cartilage over time, with pain, swelling and stiffness. Frequently affects the hips, knees, hands and spine.

Osteoporosis

A condition in which bone becomes weaker and more fragile, increasing fracture risk. It is more common in older adults, particularly postmenopausal women, and can often be managed with medication and lifestyle measures.

Sprain

A stretch or tear of a ligament, the tissue connecting bone to bone. Sprains are common in the ankle and wrist.

Strain

An injury to a muscle or tendon, often from overstretching or overuse.

Tendinopathy and tendonitis

Pain and change within a tendon, often related to repeated load or overuse, with pain, swelling and stiffness. Common examples include tennis elbow and Achilles tendon problems.

Trigger finger

A condition in which a finger catches in a bent position then releases suddenly, caused by irritation of the tendon and its sheath.

Why this matters

Understanding the terms used in your care makes it easier to ask the right questions and take part in decisions. If any term in your own reports or consultations is unclear, ask your treating clinician to explain it.

You can find the right care pathway, read about the Fracture and Injury Clinic, or book an appointment.