Run out with elbow

There was a contentious incident in a recent Test Match involving Pakistan and England when Yasir Shah was run out by a combination of Chris Woakes' arm and Jonny Bairstow’s elbow.
Sarfraz Ahmed called Yasir Shah for a second run but the No. 8 was always going to struggle to make his ground. He put in a leap at the end of the run, the third umpire was called into play, and he was given out – despite the ball never having actually touched the stumps. It was a fair dismissal as the ball was in Bairstow’s hands when his elbow knocked the stumps down.
As MCC’s Law 28 states, as long as it is the arm being used of the hand which has the ball, it would be a run out. Had Bairstow knocked the stumps over with his legs or any other part of his body with the ball in his hands, it would not have been out.

Law 28 – The wicket is put down if a bail is completely removed from the top of the stumps, or a stump is struck out of the ground by a fielder with his hand or arm, providing that the ball is held in the hand or hands so used, or in the hand of the arm so used

Read more about Law 28 (The wicket is down) at the MCC website