In this article, I will discuss the basic and relevant anatomy of the shoulder and scapulothoracic joints as a reference for future articles that address how shoulder anatomy plays a role in the golf swing. This is a good place to start for student strength coaches and PT’s and for golfers who want to learn more about how their body works.
WARNING: it will not be the most exciting article, but rather lays a foundation for future articles.
The shoulder is a ball and socket joint with 3 degrees of freedom.
The primary osteokinematic motions at the shoulder occur in the:
-Sagittal plane: flexion and extension
-Frontal plane: abduction and adduction
-Transverse plane: internal and external rotation
Static stabilizers– Structures that provide stability regardless of muscle activation or volitional control.
- The labrum
- The labrum acts to deepen the socket of the glenoid fossa of the scapula and improve congruency between the ball and socket.
- The ligamentous capsule
- The joint capsule of the shoulder is comprised of ligamentous tissue that surrounds the entire glenohumeral joint and provides stability. The capsule also provides negative intra-articular pressure (suction) that helps to create stability
Dynamic Stabilizers- Primarily muscles that provide stabilization by contracting during active movement of the body.
- The rotator cuff
- The rotator cuff is composed of 4 muscles: the infraspinatus, teres minor, supraspinatus, and subscapularis. Collectively, these muscles act together to hold the head of the humerus in the center of the glenoid fossa, thus adding dynamic stability to the joint.
The scapulothoracic joint is not a true joint by definition, but plays a vital role in shoulder complex movement. The scapulothoracic joint is formed by the shoulder blade (scapula) and the rib cage (thorax). The scapula is relatively mobile along the wall of the thorax and must move in rhythm with the glenohumeral joint to produce smooth and clean movement of the shoulder complex. The scapulothoracic joint movements are quite complex, but I will present them in a simple manner. The movements of the scapula include:
- Protraction and Retraction
- Elevation and Depression
- Anterior and Posterior Tipping
- Internal and External Rotation
Adequate movement of the scapula during overhead motion of the shoulder is essential to proper shoulder health. When assessing the shoulder of a golfer, which I will address in a separate post, it is important to examine glenohumeral and scapulothoracic motion.
More to come!