Differential Diagnosis for Decreased External Rotation of Shoulder

• Single most likely diagnosis
  • Adhesive capsulitis (Frozen Shoulder): This condition is characterized by inflammation and scarring of the tissues surrounding the shoulder joint, leading to decreased mobility, including external rotation. It is a common cause of limited shoulder motion and is often seen in individuals with a history of shoulder injury or surgery.
• Other Likely diagnoses
  • Rotator cuff tendinitis or tear: Inflammation or tears in the rotator cuff muscles can lead to decreased strength and mobility of the shoulder, including external rotation.
  • Shoulder impingement syndrome: This condition occurs when the tendons of the rotator cuff muscles become pinched between the bones of the shoulder, leading to pain and limited mobility.
  • Glenohumeral osteoarthritis: Wear and tear of the joint cartilage can lead to decreased mobility and pain in the shoulder, including limited external rotation.
• Do Not Miss diagnoses
  • Proximal humerus fracture: A fracture of the upper arm bone can lead to decreased mobility and pain in the shoulder, including limited external rotation. Missing this diagnosis could lead to improper healing and long-term disability.
  • Brachial plexus injury: Damage to the nerves that control the muscles of the shoulder can lead to weakness and limited mobility, including decreased external rotation. Prompt diagnosis and treatment are crucial to prevent long-term nerve damage.
  • Septic arthritis: Infection of the shoulder joint can cause severe pain, limited mobility, and systemic symptoms. Delayed diagnosis and treatment can lead to joint destruction and long-term disability.
• Rare diagnoses
  • Osteonecrosis of the humeral head: A rare condition where the bone tissue of the upper arm dies due to lack of blood supply, leading to pain and limited mobility in the shoulder.
  • Rheumatoid arthritis: A chronic autoimmune disorder that can cause inflammation and damage to the joints, including the shoulder, leading to limited mobility and pain.
  • Parsonage-Turner syndrome: A rare condition characterized by sudden onset of shoulder pain and limited mobility, often accompanied by weakness and atrophy of the muscles.