Word Building Rules

Introduction

Understanding medical terminology requires mastery of word parts and the rules for combining them. This foundational knowledge enables students to interpret, construct, and define medical terms accurately.

• Word parts include roots, prefixes, suffixes, and combining forms.

• Success in medical terminology depends on learning these components and their rules.

Word Root

Definition and Application

The word root is the basic foundation of a medical term. Additional components are attached to modify its meaning.

• Word root: The core part of a word, often indicating a body part or system.

• Example: cardi (heart) in cardiologist always refers to the heart.

Combining Form

Structure and Usage

A combining form is created by adding a vowel to a word root, facilitating the joining of word parts.

• Combining vowel: Usually "o", occasionally "i".

• Used to connect word roots, especially in compound words.

• Example: myoelectric breaks down as my/o/electr/ic.

• Rule: A word cannot end in a combining form; the combining vowel is dropped and a suffix is added.

• Example: megalocardia (megal/o/card/ia) – the combining vowel "o" is dropped before the suffix "ia".

Suffix

Definition and Rules

A suffix attaches to the end of a word root, changing the word's meaning and often its grammatical function.

• Suffixes make words nouns or adjectives.

• The meaning of the suffix remains constant, but it alters the root's meaning.

• Rule: If the suffix begins with a vowel, attach it directly to the root. If it begins with a consonant, use a combining vowel.

• Example: cardiogram (cardi/o/gram) – "gram" begins with a consonant, so a combining vowel is used.

• Example: cardialgia (cardi/algia) – "algia" begins with a vowel, so no combining vowel is needed.

Prefix

Definition and Rules

A prefix attaches to the beginning of a word, modifying its meaning. Not all medical terms have prefixes.

• The meaning of the prefix remains constant, but it changes the meaning of the root.

• Example: endocardium (endo/cardi/um) – "endo" is the prefix, "cardi" is the root, "um" is the suffix.

• Prefixes attach directly to the word root; no combining vowel is needed.

Word Structure and Defining Medical Terms

Order and Method

Medical terms are constructed and defined using a specific order. Understanding this order is essential for accurate interpretation.

• Prefix at the beginning, suffix at the end, combining forms used for compound words.

• Compound words: Leuk/o/cyt/osis (combining form + word root + suffix).

• Defining terms: Always define the suffix first, then read from right to left.

• Example: carditis – "itis" (inflammation), "card" (heart) = inflammation of the heart.

• For terms with prefixes: define suffix first, prefix second, word root last.

• Example: intracardiac – "ac" (pertaining to), "intra" (within), "cardi" (heart) = pertaining to within the heart.

• For terms naming body systems or parts: define suffix first, then body organs in the order studied.

• Example: cardiopulmonary – "ary" (pertaining to), "cardi" (heart), "pulmon" (lungs) = pertaining to the heart and lungs.

Pronunciation Guidelines

Phonetic Rules and Examples

Medical terms often have complex spelling and pronunciation. Learning these guidelines is crucial for both speaking and writing.

• Some words are pronounced as they are spelled (e.g., febrile).

• Others use different letters for the same sound (e.g., "ph" in physiology sounds like "f").

• Common phonetic substitutions:

  • 'f' sound: f, ph

  • 'j' sound: j, ge, gi, gy

  • 'k' sound: k, c, ch, qu

  • 'n' sound: n, pn, kn

  • 's' sound: s, c, ps

  • 'sk' sound: sk, sc, sch

  • 'z' sound: z, x

Additional Pronunciation Rules

• Words beginning with "c":

  • If followed by e, i, or y: soft "c" (sounds like "s") – e.g., cervix, cyst.

  • If followed by a, o, u, or consonant: hard "c" (sounds like "k") – e.g., cancer, collagen.

• Word roots ending in "g":

  • If followed by e or i: soft "g" (sounds like "j") – e.g., laryngectomy, pharyngitis.

  • If followed by a, o, or consonant: hard "g" ("guh" sound) – e.g., laryngalgia, meningocele.

• Spelling does not always match pronunciation; study guidelines carefully.

Possessive Forms and Eponyms

Definition and Usage

Some diseases and medical terms are named after individuals, known as eponyms. The use of possessive forms depends on institutional preference.

• Eponym: A term derived from a person's name (e.g., Parkinson's disease).

• Possessive form may be used (e.g., Parkinson's disease or Parkinson disease).

• Nationality names (e.g., German measles) are not eponyms.

Summary Table: Word Building Components

Main Purpose: Classification of Word Parts

Key Rules for Word Construction

• Use combining vowels to join word roots, especially in compound words.

• Drop the combining vowel before adding a suffix.

• Attach suffixes directly if they begin with a vowel; use a combining vowel if they begin with a consonant.

• Prefixes attach directly to the root without a combining vowel.

• Define medical terms by reading the suffix first, then prefix, then root.

Examples and Applications

• carditis: "itis" (inflammation) + "card" (heart) = inflammation of the heart.

• intracardiac: "ac" (pertaining to) + "intra" (within) + "cardi" (heart) = pertaining to within the heart.

• cardiopulmonary: "ary" (pertaining to) + "cardi" (heart) + "pulmon" (lungs) = pertaining to the heart and lungs.

Additional info:

• Medical terminology is essential for accurate communication in healthcare settings.

• Mastery of word building rules aids in understanding complex medical terms and their meanings.