Introduction
This topic is a revision of the way Greek nouns entered Latin medical language and kept their Greek endings in some forms. Many anatomical, pathological and clinical terms are Greek in origin, and they are placed in one of the Latin declensions according to their ending and gender. Knowing this allows the student to find the correct nominative, genitive and plural form of a term and to read it correctly in a clinical text.
Principle of assignment
A Greek noun taken into Latin is assigned to a declension by its nominative ending, and the gender is generally kept from the Greek or taken from the Latin equivalent. The genitive singular and the plural are formed by the Latin rules for that declension, but some Greek forms are still used beside them. Greek neuter nouns ending in -ma and -on are the most common in medicine.
First declension (Greek -a, -ae)
Greek feminine nouns in -ē and -a enter Latin as first-declension nouns in -a, with genitive -ae and plural -ae. Examples are anaesthesia, -ae (loss of sensation) and diarrhoea, -ae (a flowing through). Many Greek nouns of this type are feminine and keep the same gender in Latin.