We collected 69 questions generated by physicians based on their active patient medical records. Each question was associated with a single term in a specific record (Key Term). These questions were analyzed with respect to word content and concept content. Concepts were matched to the National Library of Medicine's Metathesaurus (Meta-1). Sixty-eight Key Terms were completely matched by Meta-1 terms. Each question matched to an average of 3.7 Meta-1 terms for a total of 255 concepts. Based on word count, these 255 concepts accounted for 43%, stop words accounted for 36%, and numbers and drug trade names accounted for 3% of the words. The remaining 18% of the words could be matched to 143 concepts not in Meta-1. Review of all concepts showed that they could be divided into medical terms (Noun Concepts), modifiers (Modifier Concepts), and concepts that provided context for the questions (Relation Concepts). The majority of Relation Concepts did not match concepts in Meta-1. A vocabulary of Relation Concepts would provide a useful starting point for a computer system designed to aid physicians in answering these questions.