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"Progress always involves risks. You can't steal second base and keep your foot on first."

—Frederick B. Wilcox, American Author



This chapter investigates the ankle and foot complex. By the end of this chapter, you should be able to:

  • Identify the bones, joints, soft tissue, and muscles of the foot and ankle complex;

  • Discuss the relationship between the rearfoot and midfoot and their contribution to functional movement;

  • List muscles of the anterior, lateral, superficial posterior calf, and deep posterior calf;

  • Discuss the influence of the foot position during gait;

  • Describe the windlass function of the foot and provide examples of its use;

  • Describe commonly encountered movement disorders of the foot and how they impact the rest of the joints during closed chain function.



Chaz Michaels graduated last spring and has been working at his first professional job for about six months. Today he is scheduled to work with a patient who has pain from plantar fasciitis. Although he saw a couple of patients with this diagnosis as a student, this will be the first one he will treat on his own. He feels he knows what the examination process will include, but he is nervous about it just the same. He wants to be prepared for what he might find, so he starts to make a mental review of the items he will include in his assessment.


The ankle and foot is a complex system. It consists of 26 bones, 34 joints, and over 100 muscles, tendons, and ligaments. The ankle and foot joints can change within a single step from a flexible structure conforming to the irregularities of any terrain to a rigid weight-bearing structure in fractions of a second. The flexible-rigid characteristics of the ankle and foot complex provide many important, daily functions, including:

  • Support of the body's weight;

  • Control and stabilization of the leg on the planted foot;

  • Adjustments to irregular surfaces;

  • Compensation for more proximal segment malalignment or pathomechanics;

  • Elevation of the body, as in standing on the toes, climbing, or jumping;

  • Shock absorption in walking, running, or landing from a jump;

  • Operation of machine tools; and

  • Substitution for hand functions in persons with upper extremity amputations or muscle paralysis.

Ankle injuries, foot pain, and ankle and foot dysfunctions are common and result from the large forces that occur in the foot and ankle, even in quiet standing. Ankle joint forces up to 4.5 times body weight occur when walking on a level surface.1 As the foot sustains these large forces, it is also making final adjustments to the terrain and must compensate for motions or deviations at the knee or hip to keep the center of gravity within the small base of support. When the foot is not protected by a shoe, it ...

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