I read with interest the Teaching NeuroImage regarding the differential diagnosis of scapular winging.¹ Although neurology literature mentions that weakness of the rhomboids may cause winging,^2,3 this is likely erroneous. The rhomboids originate from C7 to D5 spinous processes and insert into the medial border of the scapula.⁴ Since the fibers are inserted into the medial border and not on the anterior and posterior aspects of the medial border, they do not have a role in holding the scapula approximated to the rib cage. Weakness of the rhomboids may cause the scapula to deviate down and out, but it would not cause winging, if winging is defined as lifting of the scapula off the rib cage. In case 2 of the article, the patient had wasting of the infraspinatus and it is likely that multiple muscles around the shoulder joint were weak. The winging of the medial border in case 2 was most likely due to serratus weakness. The winging of the medial border of the scapula in serratus weakness makes it appear that the rhomboids were weak,⁵ although clinical testing may reveal normal power of the rhomboids.

Mild scapular winging due to rhomboid weakness can be appreciated by an astute examiner. Muscles do not work alone but in tandem with other muscles for proper function and alignment. The rhomboids contribute to holding the medial border of the scapula protracted against the posterior thoracic wall, and denervation or paralysis results in the subtle winging of the medial border of the scapula as it lifts off the thoracic wall.^6,–,9 In addition, the scapula may rotate laterally along the posterior thoracic wall due to unopposed muscle contraction of the other functioning scapular muscles. The scapular winging is accentuated by having the patient extend the arm backward from a flexed position or as Dr. Tsivgoulis and colleagues showed in the figure, F and G.⁶ They had the patient push his elbow backward against resistance when the hands were on the hips.

Author Response

We agree with Drs. Amato and Greenberg that scapular winging due to rhomboids weakness may be accentuated either by having the patient extend the arm backward from a flexed position or by having the patient push his elbow backward against resistance when the hands are on the hips. We appreciate their insightful comments on our recent article.¹ We disagree with Dr. George and support current literature indicating that weakness of rhomboids may cause scapular winging. Neurologic examination of case 2 disclosed no weakness in serratus anterior muscles. Consequently, weakness of rhomboids was the cause of scapular winging in case 2.