Traditionally, the medical record was the paper chart, but due to the growth in electronic health record systems, email, the internet, etc. the definition of what is the legal medical record file is much more complex. Further, the HIPAA regulations definition of "protected health information" and the ability of a health care provider to identify the health record by policy as a "designated record set" have caused additional legal questions.
While recently looking at a chart related issue I noticed that the American Health Information Management Association (AHIMA) has published an "Updated: Guidelines for Defining the Legal health Record for Disclosure Purposes."
Thanks to Alan Goldberg for mentioning the updated guidelines on the AHLA HIT listserve.