Bruised Knuckle: Causes, Symptoms & Treatment

A bruised knuckle (contusion of the metacarpophalangeal or interphalangeal joint) typically results from punching a hard object (wall, floor, another person) with a closed fist.

Mechanism

Direct impact → capillary rupture → extravasation of blood into subcutaneous tissue and joint capsule → swelling, discoloration, pain.

Symptoms

• Pain, tenderness over dorsal hand/knuckle
• Swelling, ecchymosis (blue-purple → green → yellow)
• Limited finger flexion/extension
• Possible joint stiffness

Management

• RICE: Rest, Ice (15 min q2–3h), Compression (light wrap), Elevation.
• NSAIDs for pain/inflammation.
• Buddy taping for protection.
• X-ray if deformity, severe pain, or suspicion of fracture (boxer's fracture = 5th metacarpal neck).

Healing: 1–3 weeks. Seek care if numbness, deformity, or worsening.