The shoulders are a mysterious place for musicians and most people-Where do they start? What the heck is a rotator cuff? Is it a singular muscle? And is there a shoulder joint? It hurts when I do (blank), whats wrong with me? I've worked with students and fellow musicians on understanding the basic mechanics of our shoulder and upper arms, which is an essential piece of knowledge for instrumental teaching and performance, as well as a healthy lifestyle for non musicians.
Basic fact #1: The shoulder is composed of three bones: the humerus, the clavicle, and the scapula. No more, no less. The humerus is your upper arm bone (underneath your biceps and triceps), your clavicle is the collar bone running laterally from your sternum, and your scapulae are the wing-like bony structure on your back. The glenohumeral joint (i.e. where your humerus meets your scapula and clavicle), is a ball and socket joint (meaning that your "shoulder joint" is in fact your glenohumeral joint).
Basic Fact #2: The rotator cuff is not a single muscle, but a group of four muscles. When students or friends have a rotator cuff injury, they rarely know which one of these four muscles they've injured, which is actually a bit of an issue because they do wildly different things. Here they are:
Supraspinatus: The top-most muscle, which helps to lift the shoulder, but does little in rotation.
Infraspinatus: The middle muscle, which helps to externally rotate the shoulder, as well as adduct.
Teres Minor: The lowest muscle on the posterioir of the scapula also assists in external rotation and stabilization.
Subscapularis: This is sort of the ugly stepchild of the rotators-hidden on the front side of the scapula, towards the internal cavity, this muscle internally rotates the shoulder and is a major stabilizer. It's also the largest of the group.
Basic Fact #3: While massages can help remedy chronically tight shoulder and upper back tissues, you actually have to change the posture or habit that is creating that tension pattern in order to see lasting change. (I.e., if your shoulder rest makes your left shoulder elevate, you then get a massage, and then play the next day without changing anything, the effects won't last. The same would be true for your movement habits, yoga practice, workouts, etc.) One has to combine soft tissue work with postural change and awareness to see results. (Subtle somatic practices like Feldenkrais and Alexander technique can be great for that!)
Basic Fact #4: Your posture affects your shoulder mobility. If you're a slumper, meaning that your upper chest rounds and your head pushes forward, you're at risk for many musculoskeletal issues, (not to mention unusual tension patterns related to being a musician). Your shoulders can't move freely when your torso isn't supporting your upper body and you can't breathe as fully if your posture is compromised.
Basic Fact #5: Most people need to strengthen their rotator cuff, and most people (myself included) need to improve their upper body strength. I find that many musicians are worried about destroying their upper bodies through exercise, which is a fair concern. Yet, muscle atrophy is not helping anyone, and lack of movement aside from playing will be more detrimental in the long run. (Find a safe upper body workout, folks!). Swim, work with a personal trainer to figure out how to start a weights routine, take a yoga class with a teacher who will focus on your upper body alignment, try pilates-whatever floats your boat.