Pathologic contractures are caused by which of the following?

• A. Dehydration
• B. Aging muscles
• C. Muscle spasm or weakness
• D. Nutritional deficiency

Answer: (C)

Pathologic contractures occur when muscles or tendons shorten, leading to a decrease in the range of motion. This condition typically arises due to prolonged immobilization, muscle spasm, or muscle weakness. In the case of muscle spasm, involuntary contractions can lead to sustained tension, which prevents normal lengthening of the muscle. Muscle weakness can result from a variety of issues, including neurological conditions or lack of use, leading to insufficient counterbalance against muscle tone and spasticity. As a result, the affected muscle fibers become permanently shortened.

The other choices, while they can impact muscle function and overall health, do not directly lead to the development of pathologic contractures to the same extent. For instance, dehydration may influence muscle performance but does not inherently cause a structural change in muscle length. Aging muscles can lead to a decrease in strength and endurance, which may contribute to functional limitations but does not directly result in contracture formation. Nutritional deficiency can certainly affect muscle health, impacting overall strength and function, yet it is not a direct cause of pathologic contractures. Therefore, muscle spasm or weakness emerges as the most relevant cause of pathologic contractures among the provided options.