A 28-year-old woman is pinned by falling debris during a hurricane. An X-ray film of the leg reveals a compound fracture of the right tibia. The leg is immobilized in a cast for 6 weeks. When the cast is removed, the patient notices that her right leg is weak and visibly smaller in circumference than the left leg. Which of the following terms best describes this change in the patient's leg muscle?

A: Atrophy. The most common form of atrophy follows reduced functional demand. For example, after immobilization of a limb in a cast as a treatment for a bone fracture, muscle cells atrophy, and muscular strength is reduced. The expression of differentiation genes is repressed. On the restoration of normal conditions, atrophic cells are fully capable of resuming their differentiated functions; size increases to normal, and specialized functions, such as protein synthesis or contractile force, return to their original levels. Ischemic necrosis (choice D) is typically a complication of vascular insufficiency. Irreversible injury to skeletal muscle would be an unlikely complication of bone fracture.Diagnosis: Atrophy, bone fracture