The pectoralis minor muscle tilts the scapula forward (anteriorly) by pulling the coracoid process forward and downward (caudally).  Shortness of this muscle interferes with upward rotation of the scapula and can restrict elevation of the rib cage.  If the abdominals are short and stiff, this restriction is even more exaggerated, adding greater resistance to movement of the scapula.

Shortness of the pec minor can also contribute to thoracic outlet syndrome (TOS).

This muscle is difficult to stretch because pressure must be applied at the coricoid process, not the humerus.

When correcting the scapular position, the glenohumeral joint must remain in neutral position.  the emphasis must be on posterior tilt and not adduction of the scapula.