In 2004, Muttiah Muralitharan voluntarily performed a series of test in front of television cameras. He wore an arm brace which was moulded to the shape of his bent arm and cast with steel rods.
Muralitharan was born with a deformity commonly known as a congenital deformity of the elbow.
The video displays the two diverse angles that his elbow is bent in. Not only is his unable to fully straighten his elbow but the joint is bent outwards in a 45 degree angle.
Murali bowled with a brace which prevented any form of straightening. Australia's Micheal Slater was present at the tests to face Murali's deliveries with the brace on. Slater confirmed that Murali could bowl both his Doosra and his Off-Spinner in conditions similar to match conditions.
The video proves that Muralitharan does not require any effort from his elbow to deliver the ball, and as such his deliveries conform with Cricket's Law No. 24.