Introduction to Medical Terminology: Components, Word Roots, Prefixes, Suffixes, and Plural Endings

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Ch. 1 Introduction to Medical Terminology

Medical Term Components

Medical terms are constructed from specific word parts, each contributing to the overall meaning of the term. Understanding these components is essential for interpreting and forming medical vocabulary.

Constructed Terms: Built from word parts (roots, prefixes, suffixes, combining vowels).
Eponyms: Terms derived from people's names (e.g., Lou Gehrig’s disease).

Component	Definition	Example
Word Root	Core meaning, usually a body system or structure	cardi (heart)
Combining Vowel	Links word parts, often 'o'	cardi/o
Prefix	Added to the beginning, modifies meaning (direction, quantity, etc.)	hypo- (below)
Suffix	Added to the end, modifies meaning (condition, procedure, etc.)	-itis (inflammation)

Example: Electrocardiogram = electricity (electro-) + heart (cardi/o) + record/image (-gram)

Appendix illustration for word root 'append/o'

Defining Medical Terms:

First, define the suffix (condition/procedure).
Then, the prefix (direction, quantity, etc.).
Finally, the word root (core meaning).

Example: Hypoglycemia = hypo- (below) + glyc (sugar) + -emia (blood condition) → Low blood sugar condition.

Forming Terms from Word Parts

Medical terms are formed by combining the components in a specific order:

Determine if a combining vowel is needed (use if suffix starts with a consonant or when joining two roots).
Add the suffix to the end of the word root.
Add the prefix to the beginning of the word root.
Interpret the meaning from the components.

Example: anti- (against) + path/o (disease) + -genic (producing) = Antipathogenic (producing against disease).

Word Roots and Combining Forms

Common Word Roots

Word roots provide the core meaning of medical terms, often indicating a body part or system.

Combining Form	Definition
append/o	appendix
carcin/o	cancerous
cis/o	to cut
dermat/o	skin
encephal/o	brain
enter/o	small intestine
eti/o	cause (of disease)
gastr/o	stomach
gynec/o	woman, female
hemat/o	blood
laryng/o	larynx (voice box)
macr/o	large
mamm/o	breast
nephr/o	kidney
ophthalm/o	eye
ot/o	ear
path/o	disease
pulm/o	lung
rhin/o	nose

Crab in a car for 'carcin/o' (cancerous) Scissors cutting for 'cis/o' (to cut) Dermatologist with skin cross-section for 'dermat/o' (skin) Brain reading encyclopedia for 'encephal/o' (brain) Apple thinking of intestines for 'enter/o' (small intestine) Stomach on a truck for 'gastr/o' (stomach) Genie for 'gynec/o' (woman, female) Needle and blood for 'hemat/o' (blood) Bird named Larry for 'laryng/o' (larynx) Magnifying glass on 'A' for 'macr/o' (large) Mother breastfeeding for 'mamm/o' (breast) Kidney with book for 'nephr/o' (kidney) Ghost for 'ophthalm/o' (eye) Car with Bluetooth for 'ot/o' (ear) Virus on road for 'path/o' (disease) Pump and lungs for 'pulm/o' (lung) Rhino smelling flower for 'rhin/o' (nose)

Prefixes

Prefixes Indicating Numbers and Amounts

Prefixes can indicate the number, size, or amount related to the root word.

Prefix	Definition	Example/Memory Tool
ambi-	both	ambidextrous
centi-	hundred	centimeter
di-	two	dilemma
milli-	thousand	millimeter
mono-, uni-	one	unicycle
multi-, poly-	many, much	multicultural
nulli-	none	null and void
semi-, hemi-	half	semicircle

Two hands for 'ambi-' (both) Penny for 'centi-' (hundred) Person deciding between two options for 'di-' (two) Millipede for 'milli-' (thousand) Monocle for 'mono-' (one) Unicycle for 'uni-' (one) Many hands for 'multi-' (many) Prohibition sign for 'nulli-' (none) Earth's core for 'semi-' (half)

Prefixes Indicating Qualities

These prefixes describe attributes or characteristics of a condition.

Prefix	Definition	Example/Memory Tool
brady-	slow	Brady the turtle
dys-	difficult, bad, painful	dyslexia
eu-	good	euphoria
heter-	different	heterogeneous
mal-	bad	malfunction
mega-, megal-	very large	megaphone
neo-	new	neonate
tachy-	fast	tachometer
ultra-	beyond normal	ultra-fast

Brady the turtle for 'brady-' (slow) Dyslexia for 'dys-' (difficult, bad, painful) Euphoria for 'eu-' (good) Male and female symbols for 'heter-' (different) Malfunction for 'mal-' (bad) Megaphone for 'mega-' (very large)

Prefixes Indicating Position and Placement

These prefixes specify location, direction, or spatial relationships.

Prefix	Definition
ante-, pre-	in front of
dorsi-, dorso-	behind
infer-, infra-, hypo-	below
circum-	around
peri-	surrounding
ep-, epi-	over, above, on top of
ab-	away from
ad-	toward
ec-	outside, out
intra-	within
inter-	between
para-	beside, near
dia-	through

Abduction for 'ab-' (away from) Adduction for 'ad-' (toward) Eccentric for 'ec-' (outside, out) Intra- (within) Inter- (between) Paralegal for 'para-' (beside, near) Dia- (through)

Suffixes

General Use Suffixes

Suffixes are added to the end of word roots to modify their meaning, often indicating a condition, procedure, or specialty.

Suffix	Definition	Example
-algia	pain	gastralgia (stomach pain)
-drome	symptoms occurring together	syndrome
-cide	to kill	bactericide
-gen, -genic, -genesis	to form or produce	embryogenesis
-stasis	control/stop	hemostasis
-blast	immature cell	hepatoblast
-cyte	cell	erythrocyte
-logy	study of	hepatology
-therapy	treatment	psychotherapy
-thermy	heat	endothermy

Grammatical Suffixes

These suffixes convert word roots into nouns, adjectives, or diminutives.

Suffix	Type	Example
-ia, -osis, -ism	Noun	hyperhidrosis, embolism
-iatry, -ician, -ist	Specialist	psychiatry, pediatrician, cardiologist
-ac, -al, -ar, -ary, -ic, -ile	Adjective	cardiac, congenital, muscular, urinary, cephalic, infantile
-icle, -ole, -ula, -ule	Diminutive	ventricle, arteriole, macula, pustule

Suffixes for Pathological Conditions

These suffixes describe diseases, conditions, or symptoms.

Suffix	Definition	Example
-mania	obsession	pyromania
-phobia	fear	pyrophobia
-edema	swelling	lymphedema
-emesis	vomiting	hyperemesis
-asthenia	weakness	myasthenia
-itis	inflammation	arthritis
-malacia	softening	osteomalacia
-megaly	enlargement	hepatomegaly
-oma	tumor	carcinoma
-pathy	disease	nephropathy
-penia	deficiency	osteopenia
-phasia	to speak	aphasia
-plegia	paralysis	hemiplegia
-rrhage	bursting forth	hemorrhage
-rrhea	flow, discharge	diarrhea
-rrhexis	rupture	hysterorrhexis

Suffixes for Diagnostic and Surgical Procedures

Suffix	Definition	Example
-tomy	incision	gastrotomy
-ectomy	surgical removal	gastrectomy
-stomy	new opening	colostomy
-centesis	surgical puncture to remove fluid	amniocentesis
-desis	binding	arthrodesis
-rrhaphy	suture	herniorrhaphy
-graph	recording instrument	polygraph
-graphy	recording technique	angiography
-meter	measuring instrument	thermometer
-metry	measuring technique	spirometry
-scope	examination instrument	microscope
-scopy	examination technique	colonoscopy

Plural Endings

Rules for Forming Plurals in Medical Terms

Many medical terms have Latin or Greek origins, and their plural forms follow specific rules:

Singular Ending	Plural Ending	Example
-y	-ies	artery → arteries
-is	-es	diagnosis → diagnoses
-us	-i	nucleus → nuclei
-a	-ae	vertebra → vertebrae
-um, -on	-a	ovum → ova, ganglion → ganglia
-en	-ina	foramen → foramina
-nx	-nges	phalanx → phalanges
-ax, -ex, -ix	-ces	thorax → thoraces, appendix → appendices

Example: The plural of metastasis is metastases.

Additional info: These rules are essential for accurate communication in medical documentation and reporting.