Medical Terminology — Quick Reference
Word-building formula
prefix + root + (connecting vowel, if needed) + suffix
Connecting vowel rule:
Used when the next part starts with a CONSONANT
Dropped when the next part starts with a VOWEL
e.g. gastr/o + enter/o + -logy = gastroenterology
gastr + -itis (no "o" needed) = gastritis
Common roots
|---|---|---|
| cardi/o | heart | cardiomyopathy |
|---|
| gastr/o | stomach | gastritis |
| nephr/o, ren/o | kidney | nephrectomy, renal |
| hepat/o | liver | hepatitis |
| dermat/o | skin | dermatitis |
| oste/o | bone | osteoporosis |
| neur/o | nerve | neuropathy |
| pulmon/o, pneum/o | lung | pulmonary, pneumonia |
| myel/o | spinal cord OR bone marrow (context-dependent) | myelogram / myeloma |
| arthr/o | joint | arthritis |
| splen/o | spleen | splenomegaly |
Common prefixes
|---|---|---|
| hyper- | excessive, above normal | hypertension |
|---|
| hypo- | deficient, below normal | hypoglycemia |
| brady- | slow | bradycardia |
| tachy- | fast | tachycardia |
| a-/an- | without, absence of | anemia |
| dys- | difficult, painful | dyspnea |
| sub- | below, under | subcutaneous |
| supra- | above | suprarenal |
| peri- | around | pericardium |
Common suffixes
|---|---|---|
| -itis | inflammation | appendicitis |
|---|
| -osis | a condition (often non-inflammatory) | nephrosis |
| -ectomy | surgical removal | appendectomy |
| -otomy | surgical incision | tracheotomy |
| -ostomy | surgical opening | colostomy |
| -algia | pain | neuralgia |
| -ology | study of | cardiology |
| -pathy | disease | neuropathy |
| -emia | blood condition | anemia |
| -megaly | enlargement | hepatomegaly |
| -oma | tumor | nephroma |
| -iasis | condition/presence of | nephrolithiasis |
Latin/Greek plural forms (common traps)
|---|---|
| diagnosis | diagnoses |
|---|
| prognosis | prognoses |
| vertebra | vertebrae |
| bacterium | bacteria |
| nucleus | nuclei |
Eponyms (no decodable word parts — learn as whole terms)
Parkinson's disease, Alzheimer's disease, Crohn's disease,
Down syndrome
Decoding checklist for an unfamiliar term
[ ] Read right to left — suffix = category, roots = location
[ ] Check for a genuinely ambiguous root (myel/o, my/o) —
confirm meaning from clinical context
[ ] Check if it's an eponym — no point decoding a proper name
[ ] Check if root order encodes direction (e.g. gastroesophageal)
[ ] If still unclear or documentation-ambiguous → physician query,
with a SPECIFIC question, not a vague one
