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How to rearticulate a fox skeleton: part two


Two weeks ago I posted about my finished rearticulated fox skeleton Vulpy, and last weekend I wrote about the first half of how I did it. In the first half of my guide I wrote about doing the spine, the back legs and front legs which may seem like a lot but it's still only half way there !

The final steps are the feet, the tail, the ribs and attaching the skull.

The feet

Feet are complicated. Fox feet are like human hands. If you look at your hand you can see:

  • The carpals (the tiny complicated bones just at the wrist). In the foot these are called the tarsals.
  • The metacarpals (the bones between the wrist and first knuckle). In the foot these are called the metatarsals.
  • The proximal phlanges (the bit of finger where a wedding ring goes). 
  • The medial phlanges (the middle bit of the finger)
  • The distal phlanges (where the fingernails are).

Foxes have four metatarsals, four proximal phlanges, four medial phlanges and four distal phlanges on each paw. I sorted out the bones into rows. I had 16 (all) metatarsals/metacarpals (top row); 16 (all) proximal phlanges, 9 medial phlanges (seven missing) and 8 distal phlanges (8 missing), so I decided to do the entire bak paws and the front paws would just have the metatarsals and proximal phlanges.

This is the one of the back paws which have longer metatarsals. The bones might not be exactly right, but it shows how they fit together:

Once I sorted them I taped on a piece of paper like this.

To join them I used a bit of wire through each "finger" like a kebab. I had to drill CAREFULLY into the end of each bone. You don't have to drill the whole way because the bone is hollow in the middle. The end bones only needed one hole because they were at the end of the wire:

I cut four bits of wire for each foot and slid the metatarsals on first leaving lots of wire each side:

Then I slid on the phlanges in the right order and they looked like this. I glued the end ones (the distal phlanges) on and slid the others down.

The wire from the middle toes I wrapped round to make a tiny circle, then I folded the wire from the outer ones in and slid that wire through the circles.

Then I pushed it all in tight:

I put black thread round the first knuckle to hold them together.

This is it when we put the foot next to the back leg:

Then I cut all but one of the wires from the foot and pushed that into the hole I drilled at the bottom of the tibia.

The other three feet were done just the same.

Attaching the back legs

This is more difficult than it seems because the whole weight of the leg has to be held in the hip socket. The hip socket was a good fit but Dad didn't think glue would hold it by itself especially because one of the legs was almost horizontal and so would push down more on the joint. We drilled a hole in the pelvis like this to go into the ball of the femur.

Here are the two holes:

And this is with the two back legs in with a piece of spare wire to hold them. It looked okay but the legs could still move from side to side, so I drilled a second hole in each hip.

For the time being I put in spare bits of wire to hold it, but didn't glue it yet.

Attaching the tail (caudal vertebrae)

When I first rotted down the skeleton I thought I had all the tail bones, but when I looked again the gamekeeper must have cut off the tail before giving the fox to me. The complicated bit is that the fox sternum (bones down the middle of the chest) are thin and round, which is not like deer, sheep or pig sternums which are broad and flat. Most of the bones on the right here are sternum.

Caudal (tail) vertebrae are like other vertebrae except they don't really have a proper hole down the middle so you need to drill one.

I used wire again like in the toes.

This then fits onto the end of the coccyx like this. If you drilled a hole earlier (I didn't) it's easier.

Before you glue it on, the back legs need to be glued into the hip, then smaller bits of wire pushed through the holes to hold it in place. I don't think I mentioned gluing the hip together before, but I did. You can see thin black bits of foam in the joint. While this was drying I put an elastic band round to make a good tight fit. But DO NOT GLUE THE LEGS UNTIL YOU HAVE FINISHED WITH THE RIBS !

The ribs

The ribs was the most difficult bit. I made loads of mistakes and had to do it again twice.

First get the ribs into pairs that are the same size, then sort the pairs into order. A good way to sort them is to look at the size of the head at the top. The bigger heads go at the front. 

This was the first order I put them in BUT IT WAS WRONG ! 

The fox was missing the fourth rib on the right entirely because that was where the bullet entered it. The ribs on the left were damaged where the bullet left. This is a picture from when I originally laid out the skeleton after I dug it up which shows the missing rib:

Once the ribs were properly paired I taped them together and drilled holes at the end.

You had to be very careful because the drill hole was almost the width of the rib:

Attaching the ribs was more complicated than I thought. To start off with I used wire wrapped round the spine wire which stuck out at right angles. But after I attached the ribs like that, I realised that was wrong, and the ribs are attached at an angle. This shows both ways I did it, the wrong way and the right way.

I did different ways of attaching different ribs. The first few ribs I used a piece of wire wrapped round the spine wire.

The middle ones I did with wire drilled into the vertebrae:

The back ribs were just glue. The fit is quite good because they fit into a groove into the vertebrae which is difficult to spot at first. Once they were all on and the glue was wet, I put a strip of cardboard on the inside of the ribs with electrical tape on the other side to space them properly. Then I put a small ball in the chest to spare the ribs apart on both sides.

Then I put card round the sticky up bits of the thoracic vertebrae and a clamp on so they were all inline.

Then I left these for a day to dry in the right position before carefully taking the clamp and everything off.

Shoulderblades (scapulas)

The shoulderblades don't connect to any other bone, so they have to be fastened on separately. I used two long pieces of wire wrapped round the spine wire a few vertebrae apart.

The brilliant idea Dad had was to drill a hole through the shoulder joint and then out the back of the scapula, so a wire could connect the scapula and humerus and spine but be almost invisible.

The two wires would be wrapped together then one would be trimmed and one goes through the scapula into the humerus into a hole I drilled earlier at the right angle.

The wire was cut to the right length to go in the humerus, then glued on while I held it. The shoulder blades are high because the fox would be running. but you can move the wire behind the scapulas to get the right position.

This is the first leg going on:

This is the second front leg going on:

I glued the front feet on at the same time.

Dad did some tests with the skull and thought it might just slot on to the wire if the foam was used as well as it made a good fit with the spine hole in the skull. This is good because it means you can lift the skull off. So the end wire was but to length, then the foam went on:

then the skull went on !

I started on 22nd December and ended on the 9th December, so it took 18 days ! This was a BIG project that needed a lot of patience.

The very final step was putting it up in my room. Dad found a cheap shoe rack which you see part of in the picture above. He painted it white, and drilled through it so it could go on my ceiling. We used dental floss as thin strong wire to hold it. This is what it looks like now.

I learnt a lot about bones doing this, and how important muscles are as well, and how the bones move together while the animal is moving.  If you are interested in bones this is a good project to do.

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Bethanol Cottrell said...

This is so cool! The finished fox looks really professional! Do you have plans to do more animals?

Jake said...

Yes, a seal ! But it hasn't rotted down yet and I need to persuade mum to let me.

Psydrache said...

I'm still impressed by your work. It's so amazing, I can't find better words! If I get a whole skeleton one time, I will try to put the bones together, too :)

Sarah said...

Wow, this is amazing! My raccon has only hot glue holding it together, and it doesn't look as good.
Wait... You have a whole seal?! COOL!

Jake said...

It's definitely worth it. You find out a lot.

Jake said...

It came from someone else who reads my blog who found it and dropped it off. It's rotting down at the moment.

Hannah said...

Hey Jake awesome blog. I'm getting ready to rearticulate a bobcat skeleton and was wondering if you had any tips or suggestions. btw great work on Vuply, she looks great.

Hannah said...


Jake said...

A good tip I was given is to spend lots of time planning how the skeleton will be, and don't rush it ! There were lots of times I had to take things apart and start again which was frustrating but was for the best.

Kurasu-chan said...

Incredible! This is the only articulation reference that I can find that goes into detail about how to actually put it together. I'm using it as reference to articulate my first cat right now and it has helped SOSOSO much

Jake said...

Thanks, glad it helped !

Chinchillazilla said...

Thanks so much for this guide. I'm rotting down a dead Virginia opossum I found and look forward to rearticulating it. (I may just do the skull, though, because now it seems to be missing its left front leg, even though it was there the first day I saw the opossum. Very mysterious, because that leg was underneath it and no animals have gotten at the body!)

Jake said...

Very strange ! There's a roe deer killed by a car near me where the foxes had removed a back leg entirely within hours being hit.

Chinchillazilla said...

Yes. I found the possum shortly after it was hit by a car and moved it out of the road. It was definitely in one piece then. I thought maybe it wasn't dead, because there was no blood or visible injuries and possums are notorious for fainting when they get scared.

I think maybe the leg is buried under the scattered fur, so I'll check back later tonight (I already had one neighbor stop and ask me what I was doing in a very nervous tone of voice when I was picking it up, so I'm going to wait until it's dark!)

Melanie said...

This is THE best articulation guide I can find, and is really helping me with re-articulating my polecat skeleton! Great guide and Vulpy looks great! :)

Stefan said...

This is a really great guide and I am using it as a reference in my report as I have been contacted by my local Environmental Authorities (MEPA) to articulate a logger head sea turtle!

Definitely this guide has given me pointers which I wouldn't have thought of!

I just would like to say what a smart young man I think you are. When I was your age I never would have been able to do the stuff that you do. I'm 23 now!

Incredible! I hope you end up working in a dinosaur museum one day and articulate those massive ancient creatures!

Jake said...

Thanks Stefan !

Quill said...

I have a question. I have asked this to others that do what you do but they don't answer. I have a deer skull but I at first I didn't know to use hydrogen peroxide to whiten bones, I used bleach.... It was a mistake. But after it sat for a few years from my frustration, I have finaly wanted to work on it again. But now it's has white powder that's hard to get off as well as a few bugs that are still trying live in it. Is there a way for me to remove the powder as well as the bugs?

Jake said...

A good long soak in water, with the skull held under the surface and all air bubbles removed (put the skull upside down to help), should kill the bugs. As for the powder, it depends what it is. It might be actual flaking bone, in which case it might be difficult. Sandpaper might do it, but I wouldn't recommend it.

kenthebird said...

Jake, I've admired your work for awhile now and often consulted your posts for advice. I recently found a dead cat in the road, killed by a car. I've done a turtle skeleton and a few birds previously, so I'm familiar with many aspects of articulation. However, cats (like this fox) have ventral ribs made of cartilage that decay when maceration is used. I noticed you didn't replace them, so does the sternum just float in Vulpy? I'm curious if I should just use wires to simulate ventral ribs, or just not include them, as you did. I'd appreciate your input!

Jake said...

Vulpy doesn't have the sternum attached. I've seen it done with both wire, and wire and artificial ventral ribs.

Cajsa said...

Wow, this is awesome! I have a baby cow that I'm waiting on to rot down, when it's ready I plan on articulating the skeleton like this. I have no idea where I'm going to put it, and my mom doesn't even want it in the house haha
I am sure I will find this very helpful when I need it! Do you have any other tips to throw my way? Anything is appreciated!

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