Poor posture is often a combination of cascading, dysfunctional elements acting on our musculoskeletal system. This dysfunction is not helped by the fact we have a strong tendency towards a dominance of our internal rotators of the humerus (upper arm bone). As muscle tension imbalances set in across the shoulders and upper arms, the dominance of internal rotation places dragging tension onto the shoulder blades. This ultimately draws the shoulder blades forward that leads to inhibition and weakening of the musculature needed to counter dominant internal shoulder rotation. Let's look at all the various internal rotators to gain a better sense of these tension imbalances.