Spelling Rules for Medical Terminology

combining form + suffix that begins with a vowel


drop the combining vowel
gastr/o + -itis = gastritis (inflammation of the stomach)

combining form + suffix that begins with a consonant


keep the combining vowel
rhin/o + -plasty = rhinoplasty (surgical repair of the nose)

two or more combining forms + suffix

keep the combining vowel between the two combining forms
oste/o + myel/o + -itis = osteomyelitis (inflammation of the bone
and bone marrow)

prefix + combining form + suffix

follow general suffix rules
hyper- + glyc/o + -emia = hypoglycemia (excessive sugar in the blood)

root word / combining form that ends with the same vowel as the start
of the suffix

drop the final vowel in the root word / combining form
cardi/o + -itis = carditis (inflammation of the heart)


eponym

a medical term named after a person or place
Amyotrophic lateral sclerosis (ALS) = Lou Gherig's Disease