Forward head posture is the most common form of structural misalignment in the body. Almost everyone I meet, myself included, suffers from this problem to some degree. The bones of a body in genuine harmony line up vertically from head to toe. The ears should be directly in line with the center of the arm bone which should be line up with middle of the hip bone, which should stack above the knee and ankle.
If we have this alignment then the arm will hang from the head via the shoulder girdle. A number of our bones are meant to hang from other bones suspended from the muscles and ligaments that connect them. But this can’t happen if the bones are not lined up properly. In order for the shoulder girdle to actually hang from the head the ears have to be in line with everything else in the vertical plane. If the head and ears move forward they will take the shoulder girdle with them. The forward pull of the head drags the shoulder girdle with it and people often compensate by pulling the arm bones back rather than correcting the head.
The shoulder girdle hangs off of the head by way of the sternocleidomastoid muscle, the omohyoid, and the trapezius. It is meant to hover above the rib cage, with the only bony connection coming where the clavicle connects to the sternum. When forward head posture is involved the forward pull of the trapezius takes the shoulder girdle with it and creates tension between the upper ribs and the shoulder blades.
Our shoulder socket is a strange and shallow almost cup that can’t really be called a socket. It is made up of three bony projections that the humerus, or arm bone, hangs off of. The three bones are the coracoid process, the acromion process and the clavicle.
The humerus hangs from the shoulder socket mainly through the biceps and the subscapularis of the rotator cuff. All of the rotator cuff muscles are involved as well as the ligaments of the shoulder capsule but essentially the arm hangs from the biceps and the subscapularis.
The whole point of this post is that if we don’t have good posture, or have the slightest forward head problem, the arm will not actually hang from anything. It will be taken on an adventure of misalignment that can only be corrected with good posture.