When forming terms with multiple roots, which connecting vowel is typically used, and what rule governs its use?

• A. The combining vowel (usually 'o'); used to connect roots and suffixes unless the suffix begins with a vowel
• B. There is no combining vowel in medical terms
• C. The combining vowel (usually 'a'); used to connect roots and suffixes
• D. There is no rule; it's arbitrary

Answer: (A)

The idea being tested is how medical terms with more than one root are joined together using a combining vowel. The connecting vowel is usually o, and it is placed to link roots to other roots or to suffixes so the term is easier to say. The key rule is that you insert this combining vowel between elements when the next element starts with a consonant, but you drop it if the next element begins with a vowel. For example, hepat/o/megaly uses the combining vowel to connect the root for liver to the suffix meaning enlargement, because megaly starts with a consonant. In gastritis, the suffix -itis begins with a vowel, so no extra vowel is added, giving gastritis. This explains why the typical connecting vowel is o and why the rule matters.