The brachial plexus is an anatomical icon.
Often produced as an interview challenge, the teaching of the crossing of fibres can have some people Reaching To Drink Cold Beer or trying to recall a story about two people dancing and someone else kicking them. However you chose to learn it, the complexity of explaining it to someone else can lead to confusion.
I first tried to image the brachial plexus at a glass workshop
The vertebrae of the spine are represented on the right hand side and the five nerves of the arm appear on the left. between them is the complex crossing of the nerve fibres. The limited colours belay the complexity and as a flat object it’s hard to convey anterior and posterior aspects but it worked wonders as a science communication piece. Most people think it is some attempt at a tube map and so it can be a conversation starter.
For some time I have been mulling over the idea as to how to develop this.
As a child I was in the Guides and Scouts. I was the only person I knew who had achieved the ridiculously hard knotters badge and I was frequently incorporated into camping teams as the person who could tie knots. One of my memorable moments is tying a massive sheepshank in a field with my father so that we could launch a glider that had landed and needed a shorter tow rope. For years I wondered about how to merge the macrame plant holders you see and the brachial plexus. Macrame is too complex for this – it tends to have two strands down the middle that are hidden from view – for this I needed all of the strands to be on display – I needed decorative knotting, plaiting and braiding.
This structure would be 3D – I would be able to show anterior and posterior, medial and lateral and I could use the pots to separate out the strands and hold them in place. I could have taken a knife to a plastic pot but I went a bit further and used a ‘Sculpd’ pottery kit so that I could create two pots, one with 3 holes and one with 5 holes to hold the strands apart and display the plexus.
The result is this
The 5 strands at the top represent the nerves coming from the spine. They are made up of two different colours of string (multiple strands of each) to represent the nerves that will make the medial, lateral and posterior cords – these are the three structures that pass through the first pot.
The 5 branches, musculocutaneous, axillary, median, radial and ulnar are the strands that pass through the second pot.
By using the different colours of strings it is possible to see that each final nerve is made up of components of the spinal nerves and so explain that should any spinal nerve get damaged it would not stop the nerves of the arm from working.
It took longer to figure out how to do it than to actually produce it. My house was littered with bits of string as I learnt how to braid with 2, 3, 4, 5 and 6 strands.
I’m working on writing out the instructions – I’ll add them to the web page when I get it done.
I’m also looking at the possibility of making it into a workshop so we can have more braided plexus’ out there.
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