Houllier felt discomfort at half-time

Houllier had suffered a condition known as dissection of the aorta.

The aorta is the largest artery in the body, running up from the heart, and down the centre of the chest to the abdomen.

Branches from the aorta, akin to roads, feed the whole body with blood.

The artery is a tube made up of different layers.

The first layer is smooth, allowing blood to flow without clotting.

With a dissection of the aorta, this inside layer splits, allowing blood to seap into the space between the layers of the artery.

As the blood flows inside the aortic wall, the layers on either side may rupture again.

If the dissection is large, the stronger outer wall of the artery can split.

This would mean severe internal bleeeding and, in the majority of cases, death.

The condition can be caused by high blood pressure, and furring up of the arteries.

Aortic dissection occurs in approximately two out of 10,000 people. It can affect anybody, but it is most often seen in men 40 to 70 years old.

Prompt recognition of the problem and emergency surgery probably saved Houllier's life.