On “Resting Position Variables…” Borstad. Phys Ther. 2006;86(4):549-557.

Extract

To the Editor:

It was with acute interest that I read John Borstad’srecent article. Although the link between postural alignment deviations and musculoskeletal impairment has been suggested, it is indeed critical to support this link with objective evidence.

The author has attempted to highlight this link by demonstrating an association between postural alignment of the scapula and a structural alteration in pectoralis minor muscle length. Connections between pectoralis minor muscle length and pathomechanical alterations in scapular kinematics,¹ between pain and impairment and alterations in scapular kinematics,² and even directly between postural alignment and impairment³ have been suggested previously.

The author reported the methods for validating the palpation points that were used to infer the pectoralis minor muscle length. Anatomical landmarks were palpated and marked on cadavers. The length of the pectoralis minor muscle was measured as the distance between the 2 landmarks: the coracoid process of the scapula and the sternum at the level of the 4th sternocostal junction. Unfortunately, the sternal landmark more closely describes the origin of the sternal portion of the pectoralis major than the pectoralis minor muscle, which originates on the 2nd–5th ribs lateral to the costocartilaginous junction.^4–6 Erroneously choosing anatomical landmarks that closely resemble those of the pectoralis major muscle invalidates on its face the direct measure used in this study for the pectoralis minor muscle length and the “Pectoralis Minor Index” (Pectoralis Minor Index=pectoralis minor length/height).