The shoulder joint is the most mobile joint in the body. However, with great mobility comes great instability. There is so much detail about the shoulder joint, so I am going to keep it to focusing on what it means to maintain stability – especially in your yoga practice.
Here is a quick overview. The shoulder joint – also known as the glenohumeral joint – is comprised of the humerus (arm bone) and the scapula (shoulder blade). It is known as a ball and socket joint. Due to the scapula not having a deep groove for the head of the humerus to sit, it can be akin to setting a golf ball on a tee. Reason one why this joint is incredibly unstable. There are a few ligaments that aid in the stability of the joint – glenohumeral ligaments (reinforce the joint anteriorly), coracohumeral ligament (reinforce superiorly), transverse humeral ligament (holds biceps brachii tendon), and coracoacromial ligament (prevents head of the humerus moving superiorly). Even though there are ligaments supporting the front of the shoulder – there isn’t much muscle support in the front. Reason number two why the shoulder is not stable. Most dislocations happen anteriorly.
Then there are a bunch of muscles that aid in the stability of the joint. Today, I will focus on what I have seen in the clinic as the weakest/incorrectly used muscles of the shoulder joint. Four muscles make up the rotator cuff: supraspinatus, subscapularis, teres minor, and infraspinatus. These four muscles blend into the joint capsule giving the joint stability. Essentially, they hold the golf ball in place so it doesn’t fall off the tee. These muscles become weak/injured when overused or if the undue stress is placed upon them. The upper trapezius and levator scapula muscles (lift the shoulder blades up towards your ears) tend to be overused when weakness occurs with the rotator cuff muscles or the rhomboids/ mid and low trapezius (pull shoulder blades toward and down the spine). The upper trap and levator scap muscles tend to be over activated if you are a desk user and if you have experienced pain by the tops of your shoulder blades – these are probably the culprit muscles. When these two muscles are always working it can lead to tightness through the front of the shoulders – pectoralis muscles. All of these things combined, can lead to poor posture and rounded forward looking shoulders. As it turns out, not exactly the ideal position for many yoga poses!
While this is definitely not a comprehensive list of muscles working at the shoulder joint, when these muscles aren’t working right, tends to lead to increased instability or potential injury of the shoulder. With that said, here are some things to focus on during class:
Warrior two – draw your shoulder blades back towards your spine, this gets the scapular muscles working and brings your shoulders to a neutral position. To engage the rotator cuff muscles that perform external rotation, flip your palms so they face the ceiling.
Bridge – Walking your arms underneath you and clasping your hands together opens up the pectoralis muscles in the front of your shoulders.
Chataranga – Again, drawing your shoulder blades towards your spine (see a pattern here) decreases dumping in the front of the shoulder. I can’t say this enough in class – modify! Drop to your knees and this will take a lot of load off your shoulder and enforce you to perform this pose correctly.
Now go to class and get your sexy shoulders to work! If you notice anything is painful in class (not just normal muscle fatigue/soreness), check in with your physician or trusty physical therapist.
Shine on,
Jackie