The anesthesiologist, Dr. Patrick Yang, decorated the patient's face with a black mustache and teardrops.
A nurse's aide then took a picture of the patient, Veronica Valdez, 36, who worked at the hospital for 13 years before undergoing surgery on her finger.
"I thought she would think this is funny and she would appreciate it," Yang said in his deposition.
But Valdez said in court documents that she felt violated and was in shock.
Others have testified they saw the photo of Valdez posted on Facebook, the Los Angeles Times reported.
The incident, which took place in 2011, has prompted a state investigation and a civil lawsuit by the patient against the hospital and the doctor for allegedly breaching medical privacy.
The hospital, Torrance Memorial Medical Center, said in a statement that the incident did occur, and that Yang and the other employees involved were disciplined, but not fired.
The suit has also raised questions about hospitals' ability to protect patients' privacy with the use of smartphones and tablets, the Times said.
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