The Foot

The feet contain a quarter of the bones in the body, so it's no surprise that this part of the project can become a bit time consuming. But I think it's well worth it in the end: you'll be able to appreciate the arches of the foot and the subtle adaptations of the shape of the foot with a new concreteness and specificity.

Let's dive in....


Step 1: Gather the parts

I'm starting here with the foot that had been wired together. You'll also want some super glue, a great deal of the smallest gauge bungee cord, and some heat-shrink tubing.

Aside from this, you'll want your basic tool kit consisting of a dremel tool, a range of drill bits, and--for this project--a screwdriver.

You may notice in this photo just how loosely held together the joints of the foot are...something to keep in mind as a point of comparison at the end of the project. These floppy articulations conceal the precise architecture of the foot which forms the arches, allowing for the efficient (and flexible) transmission of force up and through the skeleton.


Step 2: Disassemble the foot

Probably a good idea at this phase to glue together the phalanges to reduce the number of small pieces that can get lost. 

Probably a good idea at this phase to glue together the phalanges to reduce the number of small pieces that can get lost. 

There is a screw holding the subtalar joint together. It takes some doing to remove it, but once you do so you can begin stripping out the wires that hold the bones together.

Be careful to keep the phalanges in order. It'll make your life much easier when you go to connect everything back together again. 

 


Step 3: Glue the foot together starting with the metatarsals

Metatarsals joined together

Metatarsals joined together

You'll notice the arches of the foot beginning to form even with just this first step. Spend some time lining up the articulating joint surfaces. If it seems like things aren't fitting in a very snug way that creates an arch, then you may not have the joint surfaces lined up just right.

The same applies as you move back to the cuneiform and the cuboid. These things will fit together tightly and sometimes it can be easy to get mistaken. I almost glued in the middle cuneiform with the front facing back. It almost would have fit

Cuboid and cuneiforms

Cuboid and cuneiforms

Navicular added over the cunieform

Navicular added over the cunieform


Step 4: Drill holes to join the midfoot

With the foot mostly in place, you can begin to visualize where you would like the drill holes to be in order to bind the surfaces together. I began by using a 1/64'' bit and continued to bore them out up to 1/8'' in order to accommodate multiple bungee cords. 

NOTE: there are more holes to be drilled than are shown in these pictures (click on the picture to enlarge it). But this will get you started.

Pilot holes

Larger 1/8'' holes. 


Step 5: Bind the midfoot together with bungee cord

Tying these things together takes some time and you may find that the hole is slightly too narrow for 3 or 4 cords. 

It may be a good idea to err on the side of caution and make the holes a bit larger than you think you need at first.

NOTE: Here you will see some additional drill holes that connect the calcaneous to the cuboid. 

 


Step 6: Join the subtalar

You'll ultimately have three bonding points between the talus and the rest of the foot. One to the cuboid (pictured above) and two to the calcaneous (pictured below). 

Securing the talus to the sustentaculum tali

Joining the posterior-inferior talus to the calcaneous


Step 7: Secure the phalanges with heat shrink tubing, and stabilize the metatarsals with a cord

Use a 3/4" heat-shrink tube and join MTP joints 2-5 together, and the 3/8" tubing to join the associated phalanges. The great toe requires a few sets of drill holes to stabilize the 1st MTP joint. Also, additional drill holes should be made to join the metacarpals, as pictured. 


There it is. You now have the whole foot articulated and ready to bind together the lower leg, which will complete the entire lower extremity.

 

 

 

Anatomical Sketch: By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body Plate 291, Public Domain, https://commons.wikimedia.org/w/index.php?curid=792380