Pistorius has pleaded not guilty to a charge of premeditated murder and four other gun charges. At the court, he rejected the allegations "in the strongest terms".
Reeva Steenkamp,29, was injured and later dead by the bullets Pistorius fired into his toilet door.
When the graphic details of the murder was read out in the court, the Olympian clasped his head between his hands and cried. His lawyer read out details from the post mortem, which said that "some fragments of the bullet" were removed from Steenkamp's head.
One of the witnesses, Dr Burger, claimed that she heard Steenkamp's terrified scream just after the final shot was fired.
Barrister Barry Roux refuted this claim saying that it was 'physically impossible' for her to scream as the final bullet had struck Steenkamp in the head, puncturing her brain.
According to the barrister, the first bullet fired by Pistorius struck Steenkamp in the right thigh and the second missed her and instead lodged in the bathroom wall. A third shot hit her shoulder, while the fourth struck her head.
As the arguements went on, Pistorius burst into tears.