Commander Dizaei allegedly falsely arrested an Iraqi web designer
An officer who claimed he was assaulted in a row with a suspect suffered injuries which a doctor believed were "self-inflicted", a court has heard.
Police commander Ali Dizaei, 47, is alleged to have assaulted and falsely arrested man and then lied about it.
He denies charges of assault, false arrest, misconduct in public office and perverting the course of justice.
Southwark Crown Court heard from a doctor who examined Mr Dizaei after his alleged attack.
Prosecutors claim Mr Dizaei falsely arrested Iraqi web designer Waab al-Baghdadi, 24, lied about an assault and left the young businessman facing a police inquiry.
Mr Dizaei told police at Hammersmith he was "stabbed" or "poked" in the stomach at the Persian Yas restaurant in Kensington, west London, on 18 July 2008.
He gave officers the metal mouthpiece of a shisha pipe belonging to Mr al-Baghdadi.
Forensic medical examiner Dr Maureen Heath, who examined both men, reported seeing red marks between Mr Dizaei's abdomen and chest.
But she told the court the shape and uniform nature of the marks were not consistent with the alleged weapon.
She said that this, coupled with the fact she claimed to have seen the police commander trying to "stretch" his skin to distort the wounds, led her to conclude they were probably self-inflicted.
"The injuries were totally homogenous which would suggest that the alleged weapon was smooth and round," Dr Heath said.
Michael Mansfield QC, counsel for Mr Dizaei, showed her the shisha pipe in question, and said: "This item is completely consistent with a round object with smooth edges."
She responded: "That is completely wrong because a smooth edge would infer continuity of the end and there is no continuity there - there is a hole.
"In my opinion they were self-inflicted."
The trial continues.