The main shoulder joint is called the glenohumeral (GH) joint. However, the shoulder also works with the following 3 joints in order to achieve full function:
*This reference will focus on the GH joint, but just know that when the shoulder moves, all four joints move. The thoracic spine and ribs also have a huge impact on the mobility of the shoulder joint.
Fun fact: the GH joint is the most mobile joint in the body.
The humerus fits loosely into an area of the scapula (shoulder blade) called the glenoid cavity. The glenoid cavity is lined with soft tissue called the labrum, which helps to support and protect the joint. The glenoid cavity is relatively small when compared to the head of the humerus, which is another reason why the joint can be so mobile.
The ligaments of the shoulder provide a large amount of support for this highly mobile joint. The muscles surrounding the joint must also work together to give it supports. The muscles of the rotator cuff are especially important in maintaining its stability.
Ligaments of the shoulder
*Click on the images below to view the muscles surrounding the shoulder joint
Note: a lot of muscles that help move the shoulder connect to the neck as well. This means that decreased flexibility in the shoulder can affect the neck, and vice versa.
Fun fact: When you lift your arm above your head, 120 degrees of that movement is from your GH joint and 60 degrees is from your scapulothoracic joint.
Major muscles of the shoulder, categorized by function:
Flexion: anterior deltoid, biceps and serratus anterior.
Extension: posterior deltoid, triceps and lattissimus dorsi.
Abduction: anterior/lateral deltoid and supraspinatus.
Adduction: latissimus dorsi, subscapularis and teres major.
External rotation: infraspinatus and teres minor.
Internal rotation: subscapularis, lattissimus dorsi and teres major.
1. Plank on the rings: keep rings turned out and good midline stabilization
2. Paralette stabilization: keep shoulders back and down. Progress to ring dip stabilization, using a band if you need the extra support)
3. Alphabet series: V, T, W, I, Y
* For all of these, keep your shoulder blades slightly back and down to avoid using your upper trap and maintain good midline stabilization. Also make sure you are using a light weight (0 – 5lbs), doing sets of 10-15 and moving slow and controlled in both directions.
– V and T: start with only raising your arms up to shoulder height, especially if you have shoulder problems
– W: start lying on your side and work your way into standing. A lot of people are limited with internal and external rotation, so only move through your range to avoid losing good form (the 3rd and 4th repitition of the standing W shows bad form with the shoulders coming forward).
– I: start with your back flat on the wall, only moving through your available range, reaching with your finger tips and keeping your arms close to your head (The 3rd and 4th repetition of the I shows bad form, raising up higher than her available range). Once you have mastered this, try it away from the wall and progress to the Y.
Shoulder mobility videos from Kelly Starrett’s MobilityWOD