Shoulder placement can be very confusing. We hear so many cues: drop your shoulders, pull them back, squeeze them together. When is it appropriate to perform these actions and why? And what the heck does “deepen your armpits” mean? I hope to answer some of these questions for you.
The shoulder is the most mobile joint in the body, which means there are many options of where it can be in space. This could explain why it’s so confusing to place the shoulder in the correct position. Understanding how the shoulders should be placed when weight bearing on the arms is extremely important for the health of the shoulders. There are 5 joints in the shoulder but we’re only going to focus on two:
glenohumeral joint – where the arm bone, or head of the humerus, fits into the glenoid fossa, or “socket”, comprised of the lateral shoulder blade and lateral collar bone
scapulothoracic joint – which is where the shoulder blades are on the ribcage itself.
In neutral, the shoulders actually reside about 15 degrees forward of the midline, called scaption. This allows us to easily perform all our daily activities such as computer work, driving, cooking, etc., where all the action is in front of us. In tadasana however, we want to counter that action and open the heart center by drawing the shoulder blades slightly toward the midline using the rhomboids and middle trapezius. Relating our two joints’ actions; in the glenohumeral joint the arms externally rotate and in the scapulothoracic joint the scapulae retract, or “squeeze” towards the midline. There are a small percentage of these actions in tadasana and other neutral spine poses such as triangle, and a much larger percentage of these actions in big heart openers such as cobra, upward dog and bow pose.
However, when the arms are above the head the rules change. The movement in the scapulothoracic joint becomes that of upward rotation. Upward rotation is an important movement to understand. It is when the shoulder blade spins in the frontal plane (like turning a knob) and the bottom tips of the shoulder blades begin to face out laterally. What’s confusing is that the side tips of the shoulders do lift and rhomboids actually have to relax and lengthen. So pressing the shoulders down, or squeezing them together when the arms are above the head is actually a counter cue that is often misunderstood. If the arms were properly externally rotated in the glenohumeral joint, the heart will automatically be open, and if the scapulae are properly upwardly rotated in the scapulothoracic joint, “dropping the shoulders” when the arms are overhead doesn’t have to happen so long as the medial shoulders stay relaxed.
Scapular rotation happens very rapidly up to the first 90 degrees of lifting the arms “out to the sides and up”. From the point when the glenohumeral joint is at 90 degrees (arms out to a “T”) the arms do most of the movement to lift the rest of the way overhead.
When the arms are overhead, the movement in the glenohumeral joint is that of strict, unwavering external rotation otherwise there could be a pinching of the supraspinatus tendon and/or the subdeltoid bursae. This scenario could lead to muscle imbalance, pain, rotator cuff tear or frozen shoulder. The scapulae and humerus placement is crucial to understand when weight bearing on the arms in a neutral pose such as downward dog and even more so in heart opening poses such as full wheel. When arms are overhead such as urdvha hastasana, downward dog, or wheel, instead of “dropping your shoulders”, externally rotate your arms even more which screws them into the glenohumeral joint. It’s ok to lift the lateral sides of the shoulders, but not the medial side. The rhomboids and its neighbor levator scapulae need to relax in order to upwardly rotate the scapula, so to open the heart, press the entire shoulder blade forward into the back of your ribs which reinforces the stability of the scapulothoracic joint.
Remember that scaption, the neutral position of the shoulders, is about 15 degrees forward of the midline. The more the arms externally rotate, the more they must come forward, in order for the head of the humerus to rest more deeply and safely into the socket (glenohumeral joint).
From an outside perspective this action “deepens the armpits”. A flat armpit means your humerus is not in the glenohumeral joint and it is internally, not externally rotated. This could stem from very tight latissimus dorsi and/or pectoralis major but could also stem from the improper cue of having the “arm bones next to the ears”. My preferred cue is “arm bones next to cheek bones” which is again scaption, and allows for the arm to externally rotate even more, which is what we want, as it reinforces the glenohumeral joint. If you do have shoulder pain and/or tightness in your latissimus dorsi or pectoralis that prevent you from lifting your arms freely and deepening your armpits, you really should not be practicing downward dog at all. Your best bet would be to practice downward puppy and strongly work the external rotation of your arms while deepening your armpits. This along with specific stretches for your pectoralis and latissimus dorsi should get you towards a safer downward dog, or wheel with less pain and hopefully less confusion.