Medical Terminology cheat sheet

A medical term is built from a root plus optional prefix and suffix; the suffix often determines whether the term names a condition, procedure, or process.

A combining form is a root plus a combining vowel, written as root/o, such as cardi/o.

The combining vowel is usually o; it makes pronunciation easier and does not change the root meaning.

Drop the combining vowel before a suffix beginning with a vowel, as in gastr/o + -itis = gastritis.

Keep the combining vowel before a suffix beginning with a consonant, as in gastr/o + -megaly = gastromegaly.

When two roots are joined, keep the combining vowel between them, as in gastr/o + enter/o + -logy = gastroenterology.

Prefixes modify meaning or location but generally do not change the part of speech; suffixes often do.

To decode an unfamiliar term, start with the suffix, then the prefix, then the root or roots.

Prefix a- or an- means without or lack of; a- commonly precedes consonants and an- precedes vowels.

Prefixes hyper- and hypo- mean excessive or above and deficient or below, respectively.

Prefixes brady- and tachy- mean slow and fast, respectively.

Suffix -itis means inflammation; -ectomy means surgical removal; -otomy means incision; -ostomy means creating an opening.

Suffix -algia means pain; -rrhea means flow or discharge; -rrhage means excessive bleeding; -rrhaphy means suture.

Suffix -emia means a blood condition; -uria means a urine condition; -penia means deficiency.

Suffix -plasty means surgical repair; -pexy means fixation; -desis means binding or fusion; -lysis means breakdown or loosening.

Prefixes endo-, epi-, inter-, intra-, sub-, and supra- mean within, upon or above, between, within, under, and above, respectively.

Anatomical position is standing erect, face forward, arms at the sides, and palms facing forward.

Anterior or ventral means front; posterior or dorsal means back; superior or cranial means toward the head; inferior or caudal means toward the feet.

Medial means toward the midline; lateral means away from the midline; proximal means nearer the trunk or origin; distal means farther away.

The sagittal plane divides the body into right and left portions; the midsagittal plane divides it into equal halves.

The frontal or coronal plane divides the body into anterior and posterior portions; the transverse plane divides it into superior and inferior portions.

The dorsal cavity contains the cranial and spinal cavities; the ventral cavity contains the thoracic and abdominopelvic cavities.

The diaphragm separates the thoracic cavity from the abdominopelvic cavity.

The abdominopelvic quadrants are RUQ, LUQ, RLQ, and LLQ; the nine regions include epigastric, umbilical, and hypogastric areas.

Cardiovascular terms use cardi/o for heart, angi/o for vessel, arteri/o for artery, ven/o for vein, and -emia for a blood condition.

Respiratory terms use pulmon/o for lung, bronch/o for bronchus, laryng/o for larynx, pharyng/o for pharynx, trache/o for trachea, and pleur/o for pleura.

Digestive terms use gastr/o for stomach, enter/o for intestine, hepat/o for liver, cholecyst/o for gallbladder, pancreat/o for pancreas, and col/o for colon.

Urinary terms use nephr/o for kidney, cyst/o for bladder, ureter/o for ureter, urethr/o for urethra, and -uria for a urine condition.

Nervous system terms use neur/o for nerve, encephal/o for brain, myel/o for spinal cord or bone marrow, and mening/o for meninges.

Musculoskeletal terms use my/o for muscle, oste/o for bone, arthr/o for joint, chondr/o for cartilage, and tendin/o for tendon.

Endocrine and reproductive terms use thyr/o for thyroid, adrenal/o for adrenal gland, hyster/o for uterus, orchid/o for testis, and mamm/o for breast.

Integumentary and sensory terms use dermat/o for skin, onych/o for nail, ot/o for ear, ophthalm/o for eye, and rhin/o for nose.

Latin-derived terms ending in -a usually form the plural with -ae, as vertebra becomes vertebrae.

Terms ending in -is often form the plural by changing -is to -es, as diagnosis becomes diagnoses.

Terms ending in -um often form the plural with -a, as bacterium becomes bacteria.

Terms ending in -us often form the plural with -i, as nucleus becomes nuclei.

Terms ending in -on often form the plural with -a, as ganglion becomes ganglia.

Common vital-sign abbreviations include BP for blood pressure, HR for heart rate, RR for respiratory rate, and Temp for temperature.

Common laboratory abbreviations include WBC, RBC, Hgb, Hct, and CBC for white blood cells, red blood cells, hemoglobin, hematocrit, and complete blood count.

Common route and frequency abbreviations include PO by mouth, NPO nothing by mouth, PRN as needed, stat immediately, and b.i.d. twice daily.