How does a contracture occur in muscle?

Contractures in muscles can occur due to various factors that lead to the shortening and stiffening of muscle fibers. The most common causes of contractures include:

1. Immobilization: Prolonged immobilization of a limb or joint, such as after a surgery or injury, can cause the muscles to shorten and weaken, leading to contractures. Without regular movement and stretching, the muscles become tight and stiff, restricting joint range of motion.

2. Neurological Conditions: Certain neurological conditions, such as stroke, spinal cord injuries, or cerebral palsy, can affect the communication between the nervous system and the muscles. This impaired neural control can result in muscle spasms, increased tone, and contractures.

3. Muscular Dystrophies: Muscular dystrophies are genetic disorders that cause progressive muscle weakness and degeneration. As the muscles lose strength, they may become fibrotic and develop contractures.

4. Burns and Trauma: Severe burns or trauma to the skin and underlying tissues can cause scarring and contractures. The formation of scar tissue can restrict the movement of muscles and joints.

5. Muscle Diseases: Some muscle diseases, such as polymyositis and dermatomyositis, can cause inflammation and damage to muscle fibers, leading to contractures.

6. Ischemia: Reduced blood supply to a muscle, such as due to prolonged compression or vascular insufficiency, can cause muscle damage and contractures.

7. Congenital Factors: In some cases, contractures can be present from birth (congenital). These congenital contractures can be related to genetic conditions or abnormal fetal development.

8. Dupuytren's Contracture: Dupuytren's contracture is a condition characterized by thickening and shortening of the palmar fascia in the hand, causing the fingers to bend into the palm. The exact cause is unknown, but genetic factors and certain medical conditions are associated with it.

Contractures can cause joint stiffness, pain, limited mobility, and functional impairment. Treatment typically involves physical therapy, exercises, splinting, and sometimes surgical intervention to release the contracted muscles and improve joint range of motion.