Myositis ossificans traumatica, left upper arm

This code describes the formation of heterotopic bone within the muscle tissue of the left upper arm, specifically resulting from a traumatic injury. This non-neoplastic process leads to a localized mass of mature lamellar bone within the soft tissues, often causing pain and restricted range of motion.

Use this code when documentation clearly indicates myositis ossificans in the left upper arm, directly attributable to a prior trauma. This diagnosis is typically confirmed by imaging studies (e.g., X-ray, CT scan) showing mature bone formation within the muscle, alongside a history of injury to the affected area.

• Ensure documentation specifies "traumatica" to differentiate from progressive or other forms of myositis ossificans.
• Verify the laterality and anatomical site (left upper arm) are explicitly stated in the medical record.
• Consider sequencing this code after an external cause code (e.g., V00-Y99) if the initial trauma is still being treated or is relevant to the current encounter.