One of the most common aesthetic questions potential patients ask about shoulder narrowing surgery by clavicle resection is whether rolling in of the shoulders occurs. The question actually is not whether it occurs by how significant will it be. To properly answer that question requires an understanding of clavicular bone anatomy.
While the clavicle is the only horizontally oriented bone in the body, it is not a straight bone. While it is well known that it is a lazy s-shaped bone that description, while accurate, does not convey the significance of that shape. The clavicle has two curved ends that are in reverse orientation. The inner curve as it leaves the sternoclavicular joint bends backward to meet the mid-shaft section of the bone. Conversely the outer curve of the bone at the shoulder joint bends laterally from the mid-shaft as it heads towards the acromio-clavicular joint. The curve near the shoulder is always more pronounced than the one near the sternum. When you think about the sternum being further forward than the shoulder joint these two curves gives the bone a significant anterior angulation from the shoulder.
When you factor in that the genetic male clavicle usually has stronger curves than that of the genetic female the amount of anterior angulation with the two stronger curves is greater. Since the majority of patients seeking shoulder narrowing surgery are transgender male to female, at least in my experience, an understanding of this clavicle shape answers the potential inward roll of the shoulder as clavicle length is reduced.
The clavicle shape is similar to an extended right triangle with the bone being the hypotenuse. When the hypotenuse is shortened he horizontal opposite limb is brought in which pulls down the adjacent limb. Thus in shortening the clavicle it is inevitable that the shoulder will be brought forward as well. (rolled in) BUT the inward movement is minor compared to the horizontal change.
While mathematically the anterior shoulder movement is not that much it is magnified in the immediate and early postoperative period due to the recommended elbow position. Keeping the elbows by one’s side and a bit forward takes the pressure off of the healing osteotomy site. It also feels more comfortable taking the strain off the pectorals major muscle in which a few of its most superior attachment to the clavicle have been released.
Geometry aside the long term effects of any inward shoulder roll are reduced by the return of a more normal posture. But because of the shortening of the bone there will always be some persistence of it. Aesthetically it is beneficial as an inward roll helps soften the appearance of the shoulders by de-squaring or rounding them off.
Dr. Barry Eppley
World-Renowned Plastic Surgeon