How does my rib cage impact my shoulder motion?
Improving mobility in the rib cage, thoracic spine and shoulder
The rib cage and thoracic spine affect the range of motion of the shoulder because of the shape of the rib cage as it articulates with the shoulder blade. In physical therapy, we look at the shape of one bone and the shape of the bone that it connects with and typically, there is one that is more convex-shaped and the other is concave-shaped. There is a concave-convex rule that applies in the way the bones move in relation to each other. What this means is that the concave side of one bone, in this case the shoulder blade, rests on the convex positions of the ribs and because of the concave-convex rule, the slide of the shoulder blade occurs in the same direction as the arm moves. So, when the arm reaches upward, the shoulder blade slides upward as well.
The shoulder blade typically sits in the area of the second rib to the eighth rib about 3-4 finger widths from the spinous processes(the bony prominences that you can feel running along the middle of your spine). There are 17 muscles that attach to each shoulder blade!
The position of the ribs and thoracic spine can affect the movement and position of the shoulder blade which affects the movement of the arm. Here’s an example I’d love for you to try. Round out your upper back, really slump forward letting your head come forward and your shoulders round in as well. I’ll invite you to stay in this position and try to raise your arms. Notice how much you can raise your arms and notice any tension you may feel while keeping your head and back rounded forward. Next, sit or stand up as straight as you can with the natural curve in the lower back providing a stable base of support for your rib cage and thoracic spine. Now, reach up with your arms as much as you can and notice the difference in the movement. Can you reach further? Is there greater ease? Is there any change in the tension?
The upper thoracic spine can affect arm movement as well. The upper thoracic spine has to be able to flex and extend as the arm reaches overhead. The upper thoracic vertebrae also rotate slightly toward the side that is reaching overhead. So, if there is stiffness in the end ranges of reaching overhead, you may have some limits in mobility of the upper thoracic spine.
Scoliosis or curvature of the spine can affect the position of the shoulder blade. If the spine curves, leans, and/or rotates, the ribs will change their shape over time to accommodate for the change in the spine. This has a cascade effect on the shoulder blade and collar bone. These altered bony positions in the axial skeleton will directly influence how the arm will then move.
Stiffness in the thoracic area can limit arm movement and changes in the spine and rib cage impact how the arm can move. So, I’d like to offer a few ways to help you maintain your mobility in this area.
Practice 360 degree breathing. Place your hands along the lower sides and back of rib cage. Inhale into this area by visualizing the breath traveling into the areas where you have your hands. Practice for 5-10 breaths
Lay on your back with a towel roll either vertical along your spine or horizontal along the bottom edges of your shoulder blades. Try to lay as flat as you can. Turn your palms facing upward and find a position that gives you the best chest opening. This may be with the hands by your hips, away from your body slightly, at a 90 degree angle out to the side, or even overhead. Lay here an breathe deeply for 5 minutes.
To get the upper back moving, get onto your stomach and prop on your forearms. Place a small ball approximately 6-8” at the center of your chest. Lower your head and upper chest over the ball and then lift the head and chest up and look straight ahead. Repeat this movement for 5-10 reps inhaling as you rise, exhaling as you lower.
Lay on your side with a small pillow under your lower ribs. Lift your arm up and overhead. Practice making large circles with your arm to encourage side bending and rotation. Practice on each side and remember to breathe as you create your circles!
Take good care!
Sharon
