Last week I mentioned that metatarsal pain is one of the most common and annoying foot issues. If you don’t know your metatarsal from your left elbow, please review my last post…everyone else; let’s dig into a couple of examples of why your metatarsals (abbreviated MTs) might hurt. The two pairs of feet in the cases below happen to belong to two people who I saw  at Christmas time.

Case #1:

A girl with extremely pes cavus feet (this means that her feet have really high arches like the foot in the picture below).

If this person were to walk through a puddle in her bare feet, her wet footprints would show only a heel and then her toes. (Something like the picture below).

There are a few problems with this type of foot:

  1. It tends to be more rigid and it can’t adjust when weight is put on it.
  2. Because there is less contact with the ground, the places on the foot that do touch have to bear a lot of weight.
  3. The MT heads experience a lot of pressure, and that pressure last longer during each step than it does in people who do not have such high arches.

Case #2

A man with low arches who had surgery to straighten out his first few toes few years ago, he also has a Morton’s toe (meaning that his second toe is longer than his big toe).   If this man walked through a puddle in his bare feet, his footprint would look like this:

Here are some problems with low arch feet:

  1. They are too flexible. It is like trying to stand on mashed potatoes. Feet like this spread out as soon as any weight is put on them and their arches pretty much disappear.
  2. When arches flatten out, it is likely that the foot will pronate (or roll in). Pronated feet put a lot of stress on the big toe and the second toe.
  3. People with low arches tend to stand with their toes pointing out slightly, this puts even more stress on the big toe side of the foot.

There is also one more problem with this set of feet: a longer second toe. A foot with a longer second toe is almost guaranteed to have extra pressure at the 2nd MT head. This is because when you lift your heel off the ground in order to shift your weight forward and take another step, your foot has to bend right behind your toes. If the metatarsal bone of the second toe is longer than all the other MT’s it will experience even more stress than the other toes.  Add to this the fact that a longer second toe can sometimes press against the end of the shoe, bending the toe and pushing the 2nd MT down.

             

No wonder his feet hurt!

Now, you may have noticed that these two pairs of feet are basically opposites.  So why are they having the same problem? It all comes down to PRESSURE. Both of these feet experience increased pressure at the MT heads.

Your body responds to excess pressure in a couple of ways.

  • Re-enforce the bone – add extra layers of bone to try to make it stronger. This can be a problem, especially in an enclosed space. The MT bones are all pretty close together, but in between each runs a nerve and some blood vessels (bringing blood and sensation to and from the toes). As you can imagine, extra bone can make this narrow space even tighter; irritating the nerve (sometimes called metatarsalgia) and making it really easy for the toes to “fall asleep”.
  • Swelling – sometimes your body just wants you to stop damaging a part that has been injured. The area around the sore spot is filled with fluid in order to try to protect it. This can have the same effect as adding bone to the metatarsals: it tightens everything up.
  • If these two previous reactions are not effective enough, continual MT pressure can end up creating a stress fracture.  A stress fracture usually takes a long time to develop. As the name implies, it is the result of increased stress (or pressure) in an area that is not equipped to handle it.

Ouch!

How do we fix these problems? Well, the answer is: REDUCE THE PRESSURE.  There are a variety of ways that this can be done. My next blog will delve into the solutions of metatarsal pressure.

**This is a much of a cliff hanger as can be managed in a blog about Pedorthics, if you wanted some more thrilling reading material – you are in the wrong place**

Fambai Zvakanaka

Picture Sources:

http://www.podiatrytoday.com/files/imagecache/normal/Orthotic1.png

http://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Flatfeet.jpg/300px-Flatfeet.jpg

http://www.forwardarch.com/images/flat_arch.jpg

http://www.juranring.co.uk/wp-content/uploads/2011/01/phases-of-gait-cycle.jpg

http://foot-solutions.com.au/wp-content/uploads/2011/08/mortonstoe.png

http://img.tfd.com/mk/T/X2604-T-21.png

http://www.mortonsneuromablog.org/wp-content/uploads/2011/03/mortonsneuroma2_thumb.jpg

http://www.sciencephoto.com/image/108479/large/C0044267-Stress_fracture_of_foot_image_1_of_4_-SPL.jpg

http://www.myfootshop.com/images/medical/x-rays/met_fx3_mod.jpg

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