Differential Diagnosis for Winged Scapula
Single Most Likely Diagnosis
- Serratus Anterior Muscle Weakness or Paralysis: This condition is the most common cause of a winged scapula, as the serratus anterior muscle plays a crucial role in stabilizing the scapula against the chest wall. Weakness or paralysis of this muscle can lead to the scapula protruding outward, especially on the right side if the muscle is under-developed or damaged on that side.
Other Likely Diagnoses
- Trapezius Muscle Weakness: The trapezius muscle helps in elevating and rotating the scapula. Weakness in this muscle can cause an imbalance in scapular movement, leading to a winged appearance, especially if the weakness is more pronounced on one side.
- Pectoralis Muscle Imbalance: An imbalance between the pectoralis major and minor muscles can affect the positioning of the scapula. If the pectoralis muscles on the right side are under-developed, it could contribute to the elevation of the scapula on that side.
- Scapular Winging Due to Poor Posture: Chronic poor posture can lead to muscle imbalances that result in a winged scapula. If the individual consistently stands or sits with their right shoulder rolled forward or down, it could lead to the development of a winged scapula on the right side.
Do Not Miss Diagnoses
- Brachial Plexus Injury: An injury to the brachial plexus, particularly affecting the long thoracic nerve (which innervates the serratus anterior muscle), can cause a winged scapula. This condition requires prompt medical attention to prevent long-term damage.
- Spinal Accessory Nerve Palsy: The spinal accessory nerve controls the trapezius and sternocleidomastoid muscles. Damage to this nerve can lead to weakness of the trapezius muscle, resulting in a winged scapula. Early diagnosis is crucial for effective treatment.
Rare Diagnoses
- Focal Dystonia: A rare neurological disorder that can cause involuntary muscle contractions, leading to abnormal postures, including a winged scapula.
- Poland Syndrome: A rare congenital condition characterized by underdevelopment or absence of the pectoralis major muscle on one side of the body, which can also lead to a winged scapula due to the imbalance in chest muscle development.
- Muscular Dystrophy: Certain types of muscular dystrophy can affect the muscles of the shoulder girdle, leading to a winged scapula among other symptoms.