Atlas of pathophysiology, 2 Edition

Part II - Disorders

Musculoskeletal disorders


A sprain is a complete or incomplete tear of the supporting ligaments surrounding a joint when a joint is forced beyond its normal range of motion. Joint dislocations and fractures may accompany a severe sprain. The ankle is the most commonly sprained joint. Finger, wrist, knee, and shoulder sprains are also common.


·   Falls

·   Motor vehicle accidents

·   Sports injuries


A ligament may tear at any point along the ligament itself or at its attachment to bone (with or without avulsion of bone). Bleeding and formation of hematoma are followed by formation of an inflammatory exudate and development of granulation tissue. Collagen formation begins 4 to 5 days after the injury, eventually organizing fibers parallel to the lines of stress. However, swelling, stretching, or impinging on nerves or vessels around the joint may cause neurovascular compromise. Further reorganization results in eventual strengthening of the damaged ligament, although persistent laxity may result in chronic joint instability.

Signs and symptoms

·   Localized pain (especially during joint movement) and tenderness

·   Swelling and warmth

·   Progressive loss of motion

·   Ecchymosis

Clinical Tip

Sprains are graded according to the degree of swelling and instability:

Grade I—stable, minimal swelling

Grade II—moderate instability and swelling

Grade III—gross instability, extensive swelling, and ecchymosis.

Diagnostic test results

·   Stress radiography visualizes the injury in motion.

·   X-ray confirms damage to ligaments.


·   Elevate the joint above the level of the heart for 48 to 72 hours (immediately after the injury)

·   Intermittent ice packs for 12 to 48 hours

·   Immobilizer or splint during acute phase (up to 1 week)

·   Nonsteroidal anti-inflammatory drugs and analgesics

·   Early range-of-motion exercise as tolerated

·   Acute surgical repair if indicated—notably, for ulnar collateral ligament of thumb, multiple ligament injuries of the knee or elbow due to dislocation

·   Late surgical reconstruction if indicated for chronic instability of shoulder, knee, ankle




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