Swan Neck Injury – A Fix

Swan Neck Injury?

This is what happens when you have hurt some of the tendons in a finger and it can look like a swan’s neck when you put pressure on the end of it.  This is a bad thing for a guitar or bass player.  In my case, it’s the little finger on my fretting hand.  The farther away from my thumb that I have to fret with my little finger, the less force it can support naturally.  The injury looks like this if you push directly on the end of the finger:

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What happens when you try to fret with that finger, is it will just not support any force.  This injury occurred when I was catching a basketball pass and the ball hit my little finger straight on.  Hurt like you wouldn’t believe for that day, then pain seemed to subside and the bruising went away and I didn’t think about it.  For years.  Didn’t affect my guitar, bass or keyboard playing.  Until……our worship pastor wanted to do The Meters Cissy Strut for our welcome in song; and I was on bass that week.  There’s no way to play this song on bass and have it sound right, without a pretty long pinky stretch.

So I finally saw a doctor for this.  Their solution was to make a splint out of some thermoplastic there in the office.  It was great, because I walked out of the office with something that actually supported my finger and let me fret and play that song.  Here’s what their solution looks like:

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What you can’t see is that right about where I would wear a ring on that finger, part of the thermoplastic wraps under my finger.  That’s where the force is being supported.  It works but it’s kind of uncomfortable and doesn’t feel super sturdy.  I also wanted to support the finger in a little more of a tight angle than what this splint allowed for.

I’m an engineer by vocation and by God’s wiring of my brain, and I know how to do some 3D Computer Aided Drafting (CAD) modeling, and knew that our local library has some 3D printers.  So….Time to get modeling and print something a little more elegant.

I made my model by using an on-line CAD software called OnShape .  OnShape was started by some folks that came from Solidworks, and the software has a similar workflow and feel as Solidworks.

I made the model by holding my little finger on a pad of paper, at the curvature I wanted to make the splint hold, and traced around it.  Then I make some indications of where the joints were, then measured the cross-section thickness at the joints with some cheap digital calipers I bought at Harbor Freight Tools.  Then I used that data to model my finger, and ultimately my more cool looking splint in CAD.  I also wanted to get the splint to support out past the last joint near the fingernail.  Here’s what the CAD looks like modeled up without all the dimensions:

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Today, I finally got a chance to print out my masterpiece at the Library on a Makerbot 3D Printer.  Here’s a shot of my print happening (the item in the foreground is the splint I ended up using – it was my original design scaled up 10%; behind that is the original, and the item on the right is a replacement knob I was printing for my Behringer Bass V-Amp Pro.)  The print job is about 1/4 of the way done; and the splints are being printed upside down with a bunch of supports that look like little girders in there.:

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Once it was all said and done, I had a splint, but it was pretty coarse and needed some fine tuning, which I did with a Dremel tool.  Here’s the cleaned up version (still pretty coarse, but it works) and the splint on my finger.

 

The splint, and the original from the Dr.’s office are now in my bass case.  I will be printing a couple more of these, one to put in each of my guitar cases and another one for safe keeping in case I lose one of those.

Update:  Trying to print on a different printer with a little better material with a higher melting point – so I can sand it without melting it.

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