From the site:

CHORUS is a “quick reference” hypertext for physicians and medical students. More than 1,100 documents describe:

• diseases
• radiological findings
• differential-diagnosis lists (“gamuts”)
• pertinent anatomy, pathology, and physiology

CHORUS documents are indexed topically by organ system and alphabetically by title. Docments are interconnected by a network of more than 2,200 hyperlinks.

CHORUS was developed using a “peer review” process that allowed Web-based submission and anonymous review of documents. All CHORUS documents have been reviewed (and updated as needed) within the past two years; the date of most recent update is indicated on each document.

• Nervous system
• Cardiovascular system
• Respiratory system
• Gastrointestinal system
• Genitourinary system
• Musculoskeletal system
• Multisystem entities
• Technical stuff / Miscellany