Paulius Petrasiunas, 25, died “within seconds” after he was stabbed in the chest by Sean Bulle, 20, in Heath Town, Wolverhampton on July 13 last year, jurors at Stafford Crown Court were told.
Bulle, of Clover Ley, Heath Town, denies murder.
Stafford Crown Court was told the pair argued at Flat 64 of Chervil Rise before the attack took place outside, and Paulius, also known as Paulo and Polo, was pronounced dead at 5.48pm that day.
On Thursday consultant forensic pathologist Dr Brett Lockyer told the court that sharp force injuries are caused by weapons with a cutting edge, including knives.
He said: “There are three main categories; a stab wound where the depth exceeds the dimensions on the surface – a wound 10cm deep but 1cm on the surface is a stab, caused by the thrusting of a weapon.
“The second is a slash wound, longer on the surface than it is in depth, often caused by a sweeping or cutting motion with a bladed weapon.
“The third is a puncture.”
Dr Lockyer said Mr Petrasiunas suffered a large stab wound to the chest measuring 6.5cm in length.
He added that there was an abrasion at the bottom of the wound that may have been caused by the handle or hilt of the weapon.
Dr Lockyer said the direction of the wound was upwards from left to right but that does not give any indication of the direction that the weapon was thrust into Mr Petrasiunas’s body.
He explained that the the victim’s diaphragm was cut, there was damage to his liver and to the pericardial sac which which surrounds the heart.
“There was also an ‘L-shaped’ cut to the right ventricle of the heart,” said Dr Lockyer.
“One of the three main arteries, the coronary artery, was completely cut. The wound went through the lower right lung through the back of the chest.
“This is the space between the ribs and contains the muscles for breathing.
“(The wound) did not exit through the skin at the back.”
The trial continues.