Cobra/ cotton reel techniques

[Lucy Hellberg]

Hi Steve, just a quick question. When using the above techniques, this is assessing the distal long head insertion? Many thanks
Lucy

[Stephen Bird]

Hi Lucy,

When you use the pronator teres technique you can see the individual heads independently.
In the long axis if you scan slightly towards the floor you see the long head and towards the roof the short head.
In the short axis the one closer to the ulna is the long head.
This is the great advantage of this technique. You can seperate the heads and see the enthesis , tendons and MTJ all with one technique.
Using the cobra technique the collagen that presents to you is the long head as it wraps further around the radial tuberosity.
Using the cotton reel technique you don’t see any insertions, however you can see both tendons and follow them to their MTJ.
If you slide the transducer slightly towards the hand you see short head and towards the elbow you see the long head.

Steve.

[Lucy Hellberg]

Brilliant, thank you.
Lucy

[Syed Abu Sayeed]

EXCELLENT DEMONSTRATION. JUST WANTED TO ASK , IN COBRA TECHNIQUE, WHAT ARE THE OTHER MUSCLES WHICH WE ARE SEEING. SUPERFICIAL TO BICEPS BRACHII TENDON. MANY THANKS

[Stephen Bird]

The bulk of the muscle you are using for an acoustic window is the brachioradialis muscle.

It makes a lovely window allowing a high resolution view of the tendons.

It is interesting that we don’t ever really think about brqchioradialis as it is never really injured and we are very rarely asked to assess it. But it is a really big muscle. The design features of brachioradialis mean that it is rarely pathological.

It also provides excellent protection to the superficial branch of the radial nerve in the forearm.

It is an unsung hero !!

Steve.

[Syed Abu Sayeed]

Thank you so much Steve. I will share the image. Could you please correct me. I could see three muscle bellies, if you could mark it for me, that would be great.
Regards
Sayeed

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[Stephen Bird]

Whoops !

My first answer is incorrect!!

I was thinking about the cotton reel technique when I spoke about brachioradialis, so please accept my apology.

In the cobra technique the little skinny bit of muscle just above the biceps brachii tendon is the supinator and everything superficial to the supinator is the anconeus muscle.

If you scan slightly proximally from this location you will see the supinator disappear and then you can see the elbow joint capsule (annular leg and LUCL) coming around, over the top of the hyaline cartilage of the radial head and attaching to the supinator crest of the ulna. Just superficial to the joint capsule you see a tiny artery which is the recurrent interosseous artery and the muscle superficial to the artery is again anconeus.

Sorry about the confusion with my first answer!!

Steve.

[Syed Abu Sayeed]

Thank you so much for clearing the doubt.
As I had read that it’s Anconeus, but was doubtfully as the muscle bulk looks big and I was of the opinion that it’s a relatively smaller muscle. Thanks again

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