Where exactly does the PIN (posterior interosseous nerve) start?

[Elaine Wang]

Hi Steve,

Where exactly does the PIN (posterior interosseous nerve) start? I was under the impression it’s the segment of the deep branch radial nerve when it reaches the interosseous membrane of the forearm. Hence the PIN is not in the arcade of the Fröhse. However, I often read or hear others refer it to the segment immediate after the bifurcation, where I think it should be called the ‘deep branch radial nerve’. What do you think?

Elaine

[Stephen Bird]

Ahhhh, this old chestnut.

In my humble opinion the PIN should be called the deep branch of the radial nerve once it leaves the main trunk of the radial nerve. This is the division of the radial nerve into superficial and deep branches. It should only be called the PIN when it emerges from between the supinator muscle bellies and sits on the posterior aspect of the interosseous membrane. I don’t think it should be called the PIN as it enters the space between the supinator heads at the arcade of Frohse. I think at this level it should be called the deep branch of the radial nerve. But like you say, good luck changing what everyone says these days.

Let’s start a campaign !

Steve.

[Sandra St Cyr]

I agree 100%
It is not the PIN until it emerges from the between the heads of the supinator muscle.
It’s up to us to try to teach it correctly 🙂
Sandy

[Elaine Wang]

🙂

[Stephen Bird]

Guess what,

I just read Grays Anatomy and they call it the PIN as soon as it leaves the common trunk of the radial nerve !

AAaaaaaggggggggghhhhhhhh!!!!!!

Steve

[Colm McCarthy]

I always wondered this too! Thanks.

[Stephen Bird]

YES,

It seems everyone has an opinion and consensus is hard to find.

In the end it matters little as we all know what we mean by the PIN.

It would have been simpler if it was just called the deep (motor) branch of the radial nerve!!

Steve.

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