Developmental Disabilities - 2 days till Grand Island

The history of our development as a species and of our development as individuals is written on our feet.

As humans went from the trees to the savannah, our feet changed shape from the prehensile hand-like appendages of apes to the platforms made for stability, balance, and propulsion of bipedal walking. And running.

But we retain vestiges of that old appendage. The first metatarsal (the bone connecting the big toe to the rest of the foot) shows ancient and currently useless features which suggest the toe was originally prehensile.

While we've lost most of this grasping ability (not all of us have - my husband can move his big toe independently of the rest of his foot and regularly uses it for picking up around the house) we retain the ability to flex and point our toes - an ability crucial to propelling us off the ground in our running stride.

The rubber-band like tissue partly responsible for this is the posterior tibial tendon, which runs down the inside back of the leg and attaches to the foot just under the arch. This is the tendon that has been giving me trouble.

Today I went to a podiatrist I was referred to by the American College of Podiatric Sports Medicine. I explained the pain I was having and my running history. He asked me to invert my foot (point the toes inwards - the action the PTT is responsible for) and felt along the tendon, asking if I felt any pain. I did not until he came down to my arch where the tendon inserts.

Given that the whole length of the tendon wasn't in pain, he doubted a diagnosis of tendonitis, and decided to take x-rays to see what was going on.

When he brought the x-rays into the exam room and clipped them to the light box, he studied them for several long minutes in silence, with an occasional "Hm."

I doubted he was seeing stress fractures because I figured that would probably have elicited a different reaction, but I couldn't quite tell what was so interesting.

He flipped the xrays around several times, comparing my left and right feet, looking into every step I had taken from 12 months old written on my bones.

Then he turned to me and began: "Sometimes in human development you see these unusual occurences... These things are just leftovers from human evolution."

Huh? Did I have ape-feet?

He pointed out two bright white circles on the end of my first metatarsal. "These are sesamoids. They are small extra bones embedded in the soft tissue that aid the mobility of the joint. Like your kneecap. Sometimes, people have more of these. You have one here by your navicular bone embedded in your tendon. That extra bone is moving around and irritating the tendon."

I have an extra bone in my foot? COOL!!!

Even more interesting though, is that while the bone is irritating the tendon, it is not causing tendonitis. I have pain, but I am in no danger of damaging my tendon further by running. The doctor says "If you're not into pain, you shouldn't run, but if you can run through it, that's fine."

I tell him if I wasn't into pain I wouldn't be marathoning in the first place.

So my instructions are to Advil-load before the race and grit it out for as long as I want to. I should expect to be limping for a while afterwards, but it will clear up with rest after the race. In August, I will go in to be fitted for a better pair of orthotics with cushioning for this little extra bone. Eventually, I will need to have surgery to remove it, but that may effectively be the end of my running career, so we'll put that off as long as possible.

So there it is, in my foot - the history of a species that used to use its feet to grasp tree-trunks. I'm a practical evolutionary relic. I should donate my skeleton to the Smithsonian.

Also in my feet is my personal history - the bunion that is starting to develop tells the doctor of my penchant for couture shoes, the recurring case of athlete's foot that won't heal prompts him to ask if I have a family history of diabetes and to tell me to watch my blood sugar as I get older.

The feet bear the weight of every step we take, every decision we make, and even of the decisions and fates of those before us who handed down our unique make-up that enables us to leap into the air and run, or keeps us earthbound.

So, I and my ape-foot will be running the Grand Island Marathon on Sunday. I'll keep running for as long as I can, during the marathon and beyond. And when the time comes to excise my posterior tibial tendon and rebuild my foot, hopefully it will be an achievement of the most human of human evolutions, the brain, and my foot will be better than before, a testament to forward progress and the evolutionary step that allowed us to go from vegetarianism to brain-building protein brought down by running hunters.

But if not, and I have to give up running, maybe I'll move into competitive tree-climbing.