Hi Astute, most welcome. I hope I didn't give the impression to anyone that I was dismissing the case for Christ on the grounds I just believed him to be dead on the cross due to medical knowledge alone. I was just replying with medical facts in answer to the scientific argument you passed on from another source. 
The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.
There are three layers to this sac, fibrous, serous pericardium and then the cavity itself.
It is behind you're sternum and the cartilages of the third, fourth, fifth, sixth, and seventh ribs on the left side. So as you can see, it's a large cavity.
Having worked in cardio thoracics for many years I have seen not only by pass operations but many stabbings and this is the very reason that you are to never pull a knife out when someone is stabbed in the chest cavity. You pull it out, you can kill them. It may not always puncture the pericardial cavity but the first question asked of any witnesses is " how long is the knife " and x rays always taken to see if it has punctured the sac.
It became quite a common sight to see patients being rushed to theatre with what looked like a tent pole under the covers.
Ironically enough, talking of Jesus on the cross, we had one such case where two operating tables had to be used in a " cross " like postion so the patients left hand side, with knife were pointed down and surgeons worked from the top down. That knife was approximately 6 inches and it had pierced the pericardium. So you see, that spear would be enough to pierce pericardial sac and come out the otherside. Also bear in mind that a spear of even shorter length would do it bearing the mind the angle the centureon was at, the " up " direction he would have used giving quite some power behind that stabbing movement. Try that " upward " movement at home with something like a broom handle, then try the stabbing movement with something smaller on the same level. That " upward " movement is always more powerful.
Witnesses to this over 2,000yrs ago would be forgiven for describing it as water in appearance because it is just like water but when touched it's quite sticky.
Slightly off topic, " the spear of Longius " is very interesting in itself. Not sure but the spear they believed is the one to pierce Christ's side is housed ( or was housed, not sure if they moved it ) in the Hoffburg Palace in Vienna.
Last edited by Lily; 01-12-2010 at 08:24 PM.
Never be overwhelmed by decisions, just consider the right ones and your options will be far fewer.