Scapular winging is a condition where the shoulder blade visibly protrudes from the back rather than lying flat against the chest wall. This occurs when the muscles responsible for stabilizing the scapula become weakened or paralyzed. The appearance resembles a bird’s wing extending from the back, which is how the condition gets its name. This deformity can affect one or both shoulder blades.
Understanding Scapular Winging
The scapula is a flat, triangular bone forming part of the shoulder girdle, connecting the upper arm bone (humerus) to the collarbone (clavicle). It provides a stable base for arm movements and is important for overall shoulder function. The scapula engages in various motions, including protraction, retraction, elevation, depression, and rotation, all important for full upper extremity movement.
Effective scapular control relies on the coordinated action of several muscles. The serratus anterior muscle holds the scapula against the ribcage and helps with upward rotation, while the trapezius muscle assists with elevation, retraction, and rotation. The rhomboid muscles, located beneath the trapezius, retract and elevate the scapula. This coordination ensures smooth and stable shoulder motion.
Each of these muscles is controlled by specific nerves. The long thoracic nerve innervates the serratus anterior, the spinal accessory nerve controls the trapezius, and the dorsal scapular nerve supplies the rhomboid muscles. When any of these nerves or the muscles they control are compromised, the scapula loses its ability to stay flush against the back. This disruption in muscular balance causes the scapula to “wing” or stick out, leading to abnormal motion.
Common Causes
Scapular winging results from nerve damage or muscle weakness and imbalance. Damage to the long thoracic nerve is a frequent cause, leading to weakness of the serratus anterior muscle and resulting in medial scapular winging where the inner border of the shoulder blade protrudes. Injuries to the spinal accessory nerve can weaken the trapezius, causing lateral winging, while dorsal scapular nerve damage affects the rhomboids, also leading to a form of lateral winging.
Nerve injuries can stem from various sources, including direct trauma such as blunt force impacts, sports injuries, or car accidents. Repetitive strain from overhead activities or certain occupations can also stretch or compress these nerves over time. Surgical complications, viral illnesses, or inflammatory conditions can lead to nerve damage.
Beyond nerve damage, muscle weakness or imbalance in the shoulder and back contributes to scapular winging. This can arise from overuse, underuse, or poor posture, which disrupts the natural tension and coordination required to keep the scapula stable. Structural issues like deformities of the ribs or spine can also alter scapular positioning.
Identifying Symptoms and Diagnosis
The main symptom of scapular winging is the visible protrusion of one or both shoulder blades from the back. This asymmetry may be accompanied by other signs, such as uneven shoulders or a drooping shoulder on the affected side. The degree of protrusion can vary and may become more pronounced during specific arm movements.
Individuals often experience functional limitations and discomfort. Symptoms include pain in the shoulder, neck, or upper back, along with weakness in the affected arm. Limited range of motion, particularly when attempting to lift the arm overhead, is common. A clicking or popping sensation in the shoulder during movement is also common, and fatigue can also occur.
A medical professional diagnoses scapular winging through a physical examination. They will observe the scapula’s position at rest and during various movements, often using tests like the wall push-up, where the protrusion becomes evident. To identify the underlying cause, imaging tests such as X-rays can check for bone abnormalities, while an MRI can help visualize soft tissues and potential nerve compression. Electrodiagnostic studies, including electromyography (EMG) and nerve conduction studies, can pinpoint nerve damage and determine its extent.
Management and Treatment
Management of scapular winging involves conservative treatments. Physical therapy is a component, focusing on strengthening the weakened muscles surrounding the scapula, such as the serratus anterior, trapezius, and rhomboids. Therapists also incorporate stretching exercises to address muscle tightness and provide guidance on posture correction to restore proper scapular mechanics.
Pain management strategies help alleviate discomfort, including over-the-counter anti-inflammatory medications or muscle relaxants. Activity modification is also advised to avoid movements that aggravate the condition and allow for healing. Temporary support through bracing or therapeutic taping can help stabilize the scapula and provide proprioceptive feedback for muscle activation.
Surgical intervention is considered when conservative treatments have not yielded improvement or if there is repairable nerve damage. Procedures can include nerve decompression to relieve pressure on an entrapped nerve or nerve and muscle transfers, where healthy tissue is relocated to compensate for impaired function. Scapulothoracic arthrodesis, which involves fusing the scapula to the ribs, may be performed, though this is less common due to potential limitations in arm movement.