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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