In our second week, we looked at how our ribs and mid back allow the arm to move more fully overhead. Each of the four joints that make up the shoulder complex (plus the surrounding joints of the ribs and mid back) affect one another, and affect our upper extremity movement production. This week, let’s look at how our mid back and rib posture affects our shoulders, and how our shoulder blade (also known as our scapula) contributes to our movement production.
Your shoulder blade has rhythm
Imagine your thin, triangular, incredible shoulder blades. Such an unusually shaped bone, with not a tubercle, spine or foramen wasted! The shoulder blade is perfectly adapted to perform its functions- orchestrating healthful movement of the upper extremity (along with all of the other bones of the shoulder complex).
Posture is key for shoulder blade function. The postural alignment of our mid backs, sets the foundation for our scapulothoracic joint (after all, it is the “thoracic” part of the equation). When we rest in kyphosis at our mid backs, not only do we not allow the vertebra to weight bear optimally (exposing our thoracic vertebra to bony fatigue), we also shift the shape of our shoulder blades. In kyphotic posture, our shoulder blades tend to tip forward (anterior tilt) allowing their inferior tips to move away from our body, and we tend to have the shoulder blades migrate apart (protract).
Good posture also contributes to the always important issue- healthy length and tension relationships- of the 10 major muscles that attach to the shoulder blade. Recall, all four of the rotator cuff muscles arise from the shoulder blades, before they insert around the ball of the humerus.
Posture, optimal length and tension relationships, and balanced strength are key components of creating what is known as scapulohumeral rhythm. Scapulohumeral rhythm (that is a mouthful to say, and even more so to write!) speaks to the relationship of movement between the scapula and humerus. Just as we need the mid back to move to get full arm movement, the scapula and humerus must move in coordinated ways to create functional and safe arm motion. In an idealized shoulder, the glenohumeral joint and scapulothoracic joint move at a 2:1 ratio (for every one degree of movement in the scapula, there are two at the humerus).
The biggest challenge that I have seen in my years as a clinician to healthful scapulohumeral rhythm, is poor serratus anterior strength and upper trapezius dominance. Upper trapezius dominance is the condition that causes those rock formations between your neck and shoulders. It is truly an issue with head posture, but can also be helped with strengthening the middle and lower trapezius muscle.
Strengthen Your Serratus:
The serratus anterior helps to stabilize your shoulder blade onto the muscles/ ribs. It is so important for healthy shoulder blade function. To test your strength of this crucial muscle, get into a safe plank position. Have a friend look at your shoulder blades. If it looks like the shoulder blades are lifting off of your back (we call this scapular winging) especially at their inside border, you need some strength here.
Lie on your back and reach your arms up to the ceiling, palms facing in. Make sure your finger tips line up with your eyes (slightly higher than shoulder level). Press your shoulder blades apart. You will feel a muscle kick in under your arm pit- this is your serratus anterior. Hold 10 seconds. Rest for 5, work up to 15 repetitions. If you have any pain, stop immediately and consult your PT.
Reduce Your Upper Trap Dominance:
The upper trapezius is so helpful. And, like our quads, it is a bit dominant- it can start to get out of control, trying to do all sorts of things it was not built for ( such as keeping our head and necks from falling further forward in forward head posture, or assisting a weak rotator cuff in lifting our arm). Just like we need to strengthen our gluteals to offset quadricep dominance, we must strengthen our middle and low trapezius to offset our dominant upper traps.
Strengthen Your Middle Trap:
Lie on your belly, with a towel roll under your head. Make sure your spine is in neutral alignment.
Rest your arms along your sides, palms facing down. Engage your abs and glutes, draw your shoulder blades together. Hold for 5 seconds release. Repeat 5 times. If this feels OK, on your repetitions 6-10, add a small lift of your arms, one centimeter off the earth.
If you have any pain, stop immediately, consult your PT.
Over the course of the past month we have looked at the anatomy of the shoulders, and you noted that the shoulder is actually made up of four distinct joints. You have noted the necessary mid back extension that is required for full overhead movement. You have looked at the common challenges to healthful glenohumeral (ball and socket) motion, as well as what gets in the way of good scapulohumeral rhythm.
I know the shoulders are complex- if you are interested in learning more, consider viewing our August workshop (Shoulders That Sing!), attending our orthopedic integration courses in 2022, or scheduling a one on one session with me to explore and understand your shoulders more thoroughly.