Friday, October 21, 2011

Bones and Ligaments of the Foot

The bones of the foot are organized into three regions: the rearfoot, the midfoot, and the forefoot.  The rearfoot consists of the talus, which is inferior to the tibia and the fibula and superior to the calcaneus, which is also known as the heel bone. The midfoot contains the navicular, which is located between the cuneiform and the talus, as well as four other bones: the cuneiform: medial, intermediate, and lateral, and the cuboid (from bottom to top in the image above). The forefoot consists of the metatarsals and the phalanges. Both types of bones are numbered 1 through 5, beginning with the big toe, and ending with the most lateral toe; the different sides of the metatarsals have different names—the side of each bone that is closer to the body is called the proximal metatarsal, and the side further from the center of the body is called the distal metatarsal.  The metatarsals are long bones, and are connected to the phalanges. These bones are much shorter. The big toe contains two phalanges, a proximal and a distal, while the other four toes contain three: a proximal, middle, and distal phalanx.

The tibia and the fibula, the long bones of the lower leg, are connected to each other by the anterior and posterior tibiofibular ligaments. The talus is connected to the tibia by the anterior tibiotaler ligament (ATT), and is connected to the fibula by the anterior and posterior talofibular ligaments (ATF and PTF, respectively). The ATF is a lateral ligament whose function is to prevent the foot from sliding forward in relation to the shin. In a sprained ainkle, the ATF is most commonly injured because of an inversion injury. The tibia, fibula, and talus bones articulate to form the ankle joint. The subtalar joint connects the talus and the calcaneus, using the anterior and posterior talocalcaneal ligaments. The talus is connected to the navicular, a bone in the midfoot, by the tibionavicular ligament, which is part of the deltoid. The deltoid is a triangular family of ligaments that connect different bones, although they are close enough together that if one is injured they are all injured, which is why they are referred to by one collective name. The spring ligament connects the navicular and the calcanius. It is an important ligament because it provides the support for the arch of the foot. When it is torn, the foot bones collapse because of excessive pronation, causing a great deal of pain.

3 comments:

  1. Fantastic post. When you refer to the shin you can now use the term "lower leg" -it's more medical. Your explanation of the foot and ankle gave me a clear picture of how the bones articulate and they types of forces they resist. Great job.

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  2. Hey,
    Can you take time this week while out of school and look into the knee and do a post about the 4 major knee ligaments and talk about the function of the meniscus in the knee? Bonus if you can tell me a little pearl about the genicular artery. Thanks.

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