What causes medial winging of the scapula?
Winging of the scapula is usually caused by deficit in the serratus anterior muscle due to an injury of the long thoracic nerve (Figure 1).
The long thoracic nerve arises from three nerve roots, the fifth, sixth and seventh cervical nerves (Figure 2). The long thoracic nerve then passes between the clavicle and first rib, then down along the lateral chest wall giving innervation to the serratus anterior muscle. IT is a very long nerve, that is why it is named the long thoracic nerve.
The serratus anterior muscle attaches to the medial anterior aspect of the scapula and anchors the scapula against the rib cage (Figure 3).
The scapula is the largest bone of the shoulder blade complex and has the greatest number of muscles attached to it. Although these muscles may work together or oppose each other, they coordinate their functions to work in harmony as a team.
The long thoracic nerve can be injured by trauma, pressure or neuritis/inflammation. Symptoms associated with a long thoracic nerve injury include: winging of the scapula, pain, weakness, difficulty elevating the arm, a cosmetic deformity, and spasms (periscapular muscles trying to compensate for the deformity).
Clinical Evaluation Tests
To examine a patient using the wall test, the patient will be asked to face a wall, standing about two feet from the wall and then push against the wall with flat palms at the waist level in order to identify a long thoracic nerve injury and the winging of the scapula (Figure 4).
The resistance of forward flexion is when the patient will resist the examiner's attempt to bring down the forward flexed upper limb (Figure 5).
Nonoperative treatment of scapular winging will include observation for a minimum of 18 months and wait for the nerve to recover without surgery. An MRI may diagnose a lesion that is pressing on the nerve. The doctor will also obtain an EMG and nerve studies. The patient is encouraged to do serratus anterior strengthening exercises in cooperation with physical therapy. Operative treatment usually includes a pectoralis major transfer.
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