The shoulder consists of a ball-and-socket joint formed by the humerus and scapula and their surrounding structures - ligaments, muscles, tendons - which support the bones and maintain the relationship of one to another. These supporting structures attach to the clavicle, humerus, and scapula, the latter providing the glenoid cavity, acromion and coracoid processes. The main joint of the shoulder is the shoulder joint (or glenohumeral joint), between the humerus and the glenoid process of the scapular. The acromioclavicular joint and sternoclavicular joint also play a role in shoulder movements. White hyaline cartilage on the ends of the bones (called articular cartilage) allows the bones to glide and move on each other, and the joint space is surrounded by a synovial membrane. Around the joint space are muscles - the rotator cuff, which directly surrounds and attaches to the shoulder joint - and other muscles that help provide stability and facilitate movement.
Two filmy sac-like structures called bursae permit smooth gliding between bone, muscle, and tendon. They cushion and protect the rotator cuff from the bony arch of the acromion.
The glenoid labrum is the second kind of cartilage in the shoulder which is distinctly different from the articular cartilage. This cartilage is more fibrous or rigid than the cartilage on the ends of the ball and socket. Also, this cartilage is also found only around the socket where it is attached.
It is a ball and socket joint that allows the arm to rotate in a circular fashion or to hinge out and up away from the body. It is formed by the articulation between the head of the humerus and the lateral scapula (specifically-the glenoid cavity of the scapula). The "ball" of the joint is the rounded, medial anterior surface of the humerus and the "socket" is formed by the glenoid cavity, the dish-shaped portion of the lateral scapula. The shallowness of the cavity and relatively loose connections between the shoulder and the rest of the body allows the arm to have tremendous mobility, at the expense of being much easier to dislocate than most other joints in the body. There is an approximately 4-to-1 disproportion in size between the large head of the humerus and the shallow glenoid cavity. The glenoid cavity is made deeper by the addition of the fibrocartilaginous ring of the glenoid labrum.
The capsule is a soft tissue envelope that encircles the glenohumeral joint and attaches to the scapula, humerus, and head of the biceps. It is lined by a thin, smooth synovial membrane. This capsule is strengthened by the coracohumeral ligament which attaches the coracoid process of the scapula to the greater tubercle of the humerus. There are also three other ligaments attaching the lesser tubercle of the humerus to lateral scapula and are collectively called the glenohumeral ligaments.
Functional ROM and Joint Play
Range of Motion
Upper Extremity Myotomes
Upper Extremity Cutaneous Innervation
- Active Compression Test (O'Brien's Test)
- AC shear Test
- Apprehension Test
- Belly Compression Test
- Biceps Load Test
- Biceps Load 2 test
- Pronated Load Test
- Drop Arm Test
- Full Can / Empty Can Tests
- Hawkins-Kennedy Test
- Horizontal Adduction Test
- Hornblower's Test
- Infraspinatus Test
- Jerk Test
- Labral Crank Test
- Lift off Test
- Load and Shift Test
- Neer Impingement
- O'Brien Test
- Posterior Apprehension Test
- Relocation Test
- Rent Sign
- Speed's Test
- Yergason's Test
Slap Repair Type 2 and Type 4 - Slap repair
Rotator Cuff Repair - Moon Protocol
Total Shoulder Arthroplasty - Cleveland Clinic
Total Shoulder Arthroplasty - South Shore Ortho
Bankart with Anterior Stabilization - Vanderbilt Med
Sub-Acromial Decompression - Syracuse Sports Med
AC Joint Reconstruction - Mass General Hospital