Common Prefixes and Suffixes

Medical words are built from smaller parts. This lesson adds more building blocks to your collection, covering size, location, number and common procedures, so you can decode even more of the words you come across in medical letters and conversations.

Size and degree Hypo often means under, deficient or below the expected level, while hyper means above or excessive. Hypothermia is a dangerous fall in core body temperature below 35°C. Hyperglycaemia means that the blood glucose level is too high. Macro means large, and micro means small, which is why a microscope helps you view things too small to see clearly with the naked eye. Location and direction Endo means inside, and ecto or exo means outside. Sub means under or below, and supra or super means above. Peri means around, and inter means between. Subcutaneous means under the skin. Intercostal describes the muscles between the ribs. Number Mono or uni means one. Bi or di means two. Poly can mean many or excessive, while multi means many. In polydipsia, poly means excessive, so polydipsia means excessive thirst. The term describes the symptom but not its cause. Suffixes for procedures and processes Some suffixes describe conditions, symptoms or procedures. Osis often describes a condition or process, usually an abnormal one. Algia means pain, so arthralgia means joint pain. Arthritis is a broad term for conditions affecting one or more joints, often causing pain, swelling or stiffness. Arthralgia describes a symptom, while arthritis names a category of joint condition. The terms do not form a simple mild versus severe scale. Ectomy means surgical removal, as in an appendectomy or appendicectomy, the removal of the appendix. Otomy means making an incision into a structure. Ostomy refers to an operation that creates an opening, called a stoma, which may be temporary or permanent. Oscopy refers to examination using a scope. A gastroscopy examines the upper digestive tract, usually including the oesophagus, stomach and first part of the small intestine. Putting it into practice Imagine a letter says: "Patient underwent gastroscopy. Findings: mild gastritis, no ulceration. Plan: trial of antacids, review if symptoms persist." Gastroscopy tells you that a flexible camera examination of the upper digestive tract was performed. Gastritis means inflammation of the stomach lining. The surrounding words add the rest of the meaning. The report describes the finding as mild, notes no ulcer was seen, records a treatment trial and advises review if symptoms continue. Word parts provide a starting point, but the whole sentence tells you what happened and what it means.

The same small set of prefixes and suffixes reappears across medical language, covering size, location, number, and what is being done to the body.