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Word Construction: Prefixes, Suffixes & Root Words

Duration: 55 min · Level: Foundational · Module: 2. Medical Terminology & Body Systems · Focus: terminology, prefixes, suffixes, roots, exam-prep

Learning objectives

By the end of this lesson you will be able to explain and apply:

  • Combining vowel rule
  • High-yield prefixes
  • High-yield suffixes
  • High-yield roots
  • Directional terms

You will then consolidate these ideas in the hands-on lab below.

Why this matters​

Medical terminology follows predictable rules.

Overview​

Medical terminology follows predictable rules. Every term is built from a root word (the body part or condition), a prefix (modifying the beginning), and a suffix (modifying the end). Master the 50 most common word parts and you can decode almost any term you encounter — even ones you have never seen before.

Key concepts​

Key idea

Combining vowel rule: add "o" between root and suffix when suffix begins with a consonant (cardi/o/logy); no combining vowel when suffix begins with a vowel (cardi/ac)

  • High-yield prefixes: brady- (slow), tachy- (fast), hypo- (below/under), hyper- (above/over), peri- (around), inter- (between), intra- (within), supra- (above), sub- (below)
  • High-yield suffixes: -itis (inflammation), -ectomy (surgical removal), -ology (study of), -plasty (surgical repair), -oscopy (visual examination), -otomy (incision into), -ostomy (surgical opening), -algia (pain)
  • High-yield roots: cardi (heart), hepat (liver), nephr/ren (kidney), pneum/pulmon (lung), gastr (stomach), derm (skin), neur (nerve), oste (bone), arthr (joint)
  • Directional terms: anterior/posterior (front/back), superior/inferior (above/below), medial/lateral (toward/away from midline), proximal/distal (near/far from point of attachment)
  • CEHRS exam tip: terminology questions often give you a term and ask for the definition, OR give a definition and ask you to identify the term — practice both directions
Hands-on lab

Decode 20 medical terms using only the word-part rules (no lookup): cholecystectomy, tachycardia, nephritis, hepatomegaly, arthroscopy, hysterectomy, gastroenterology, bradypnea, dermatoplasty, osteotomy.

Check your understanding​

Try to recall each answer before expanding it.

Q1. What do you know about Combining vowel rule?

add "o" between root and suffix when suffix begins with a consonant (cardi/o/logy); no combining vowel when suffix begins with a vowel (cardi/ac)

Q2. What do you know about High-yield prefixes?

brady- (slow), tachy- (fast), hypo- (below/under), hyper- (above/over), peri- (around), inter- (between), intra- (within), supra- (above), sub- (below)

Q3. What do you know about High-yield suffixes?

-itis (inflammation), -ectomy (surgical removal), -ology (study of), -plasty (surgical repair), -oscopy (visual examination), -otomy (incision into), -ostomy (surgical opening), -algia (pain)

Q4. What do you know about High-yield roots?

cardi (heart), hepat (liver), nephr/ren (kidney), pneum/pulmon (lung), gastr (stomach), derm (skin), neur (nerve), oste (bone), arthr (joint)

Q5. What do you know about Directional terms?

anterior/posterior (front/back), superior/inferior (above/below), medial/lateral (toward/away from midline), proximal/distal (near/far from point of attachment)

Next: C2.2 Cardiovascular, Respiratory & Musculoskeletal Systems →

Part of Module 2: Medical Terminology & Body Systems.