Wednesday, 30 May 2012

Why choose the ulnar artery

According to Dr Hunt the primary cause of Dr Kelly's death was

1a. Haemorrhage
1b. Incised wounds to the left wrist

This post won't discuss the near impossibility of dying from blood loss resulting from the severing of one wrist artery.  What I now want to focus on is the choice of artery to cut.

I have previously mentioned the failure of Lord Hutton and the Oxfordshire coroner Nicholas Gardiner to look at the forensic evidence with a critical eye.  Hutton and Gardiner don't have medical backgrounds of course but that shouldn't prevent them from asking at least some penetrating questions of the "experts".  If I can see problems with the presented forensic evidence surely they can as well!  Unless of course they have reason to ignore problems and anomalies .... 

It is the arteries that bring fresh oxygenated blood to various parts of the body and the veins that return the blood.  The artery in the upper arm is the brachial and in the lower arm it becomes two branches: the radial artery and the ulnar artery.

At the thumb side of the wrist we have the radial artery and this is very close to the skin surface, not more than about 5 mm deep.  It is familiar to us in a way because this is where one would commonly check a wrist pulse.  On the little finger side of the wrist is the second artery - the ulnar.  The ulnar artery is about the same size as the radial, possibly slightly bigger.  Importantly it is very much deeper in the wrist than the radial and to cut it would mean getting through tendons and nerves first.  You might just be able to feel the ulnar pulse, I have managed to do it, but it is very much more difficult to feel than the pulse in the radial artery.

It's not just the fact that it's deep in the wrist though.  Assuming, like Dr Kelly, you are right handed present your left wrist in different positions: on your knee, against the chest, on a table in front of you.  In each case it is the thumb side of your wrist that is closer to a potential blade held in the right hand.  Thus it is barely believable that anyone would cut down into the ulnar whilst leaving the radial artery unscathed.  Yet Dr Hunt is asking us to believe just that in the case of Dr Kelly.

In his report Dr Hunt writes of a deep wound that was furthest away from the wrist (in the direction of the elbow);

The ulnar artery had been completely severed and the ulnar nerve had been partially severed.  The radial artery was intact as was the radial nerve.  The wound was up to approximately 1 - 1.5 cms deep

If it wasn't for the fact that the wound was so deep I would be wondering if he had got the two arteries mixed up!

A forensic pathologist should find it well nigh unbelievable that an individual would have cut through one of his ulnar arteries without touching the close to surface radial one.  In other words they should be saying to themselves "there is almost certainly foul play here".

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