Being shoulder savvy in your yoga practice is a great asset to both being a teacher and a student. Your shoulder joint and the proper functioning of the muscles associated with the movement of your shoulder joint and shoulder girdle are paramount in yoga and many yoga postures.
When we think of the shoulder, we tend to think of only the joint itself. The shoulder girdle, the shoulder girdle consists of several bony joints, or “articulations”, which connect the upper limbs to the rest of the skeleton, along with attachment sites of the connective tissue and provide a large range of movement (hence it’s known as a ball and socket joint). The shoulder girdle may also see this referred to as the “pectoral girdle.” The main bones which form the shoulder girdle are the clavicle, the scapula and the humerus.
Shoulder Anatomy 101:
There are three main joints in the shoulder girdle, these are the glenohumeral joint (GHJ), acromioclavicular joint (ACJ), and the sternoclavicular joint (SCJ), all of which come into play in many yoga postures such as downward facing dog, upward facing dog, shoulder poses and inversions.
When asked to locate the shoulder, most often people will point to the glenohumeral joint, which provides a large proportion of the movement at the shoulder girdle; however the ACJ and the SCJ joints are just as integral in load distribution and muscular recruitment in all yoga postures. The ACJ is formed at the lateral end of the clavicle and is important in transmitting load and force through the upper limb and shoulder to the axial skeleton. The ACJ has minimal mobility due to its supporting ligaments; whereas the SCJ occurs at the sternal end of the clavicle, the cartilage of the first rib and lateral, upper portion of the sternum, which functions in all movements of the upper limbs and plays a larger role in throwing or thrusting movement patterns.
Another important (and often neglected) joint that permits movement and postural awareness is the scapulothoracic joint ; which supports movement and stabilization of the shoulder. It overlies the 2nd – 7th ribs, is tilted slightly forwards by an angle of 30°, and is encased by 17 muscles which provide control and stabilization against the thoracic wall (the ribcage). Even though it is not technically a “joint” it is referred to as one because of its functionality. This joint relies entirely on the surrounding musculature for its control and aids in movement of the skeleton and spine. During elevation the glenohumeral joint rotates 2° for every 1° of scapulothoracic rotation.
How can we protect our shoulder joint in Yoga, as well as off the mat?
Learning to engage and strengthen the rotator cuff muscles and the muscles associated with our posture is crucial to preventing common shoulder injuries. For students who lack mobility, learning how to properly improve mobility to the muscles surrounding these joints will reduce tension and force to the joint structure, as well as improve proper recruitment and motor control through movement and postures.
The rotator cuff consists of the subscapularis, infraspinatus, teres minor, and supraspinatus. This group is one of the most important but widely misunderstood structures in the body. The names of three of the muscles give you a clue to their location: subscapularis sits under the scapula, between the ribs and the front surface of the scapula. Supraspinatus sits above and infraspinatus sits below the spine of the scapula. Teres minor sits on the outer edge of the scapula, near the posterior fold of the armpit.
Its job is to support and position the ball that forms the head of the humerus and fits in the socket of the shoulder joint. The shoulder is inherently an unstable joint, so building the strength of these supporting muscles is crucial to proper functioning.
These important external rotators, infraspinatus and teres minor, are the part of the rotator cuff that is strengthened in Downward Dog. A weakened rotator cuff might lead to abnormal shoulder-movement patterns, which can contribute to inflammation and pain. Not only that, but weak muscles are likely to tear when you put a load on them that they aren’t strong enough to handle. Thus practice makes perfect, and to do so stay focused on the transitional movements and modify if necessary.
When I teach downward dog to students, I have them start in poses such as an elbow plank to dolphin pose, then from a straight arm plank moving to downward facing dog, cueing on the important of external rotation and recruitment of the shoulder girdle.
Once you’ve mastered keeping the external rotators engaged in these poses, you can apply the action to more challenging poses such as upward-Facing dog and chaturanga dandasana (Four-Limbed Staff Pose), and even into inversions and hand stands.
Adding in a little thoracic spine mobility would also support proper elongation of the spine and assist in deep breathing while moving through pose to pose. Next week we will dive deeper into the functionality of the rotator cuff muscles and it’s association with the fascial system for improved stability and mobility.