Shoulder | CrossFit South Bay



aching shoulder

Manage The Weight On Your Shoulders

You may not realize it, but you use your shoulders in almost everything that you do. Whether it’s exercising, driving or sitting at your computer at work, your shoulders are actively working throughout the day.

Your shoulders are complex. Each one consists of a ball and socket that is made up of many bones and ligaments that work together to provide you a range of motion. In order to stay mobile and be able to move your arms in different directions, it is vital that your shoulder supports such movements. Many instances can cause shoulder pain. It can be caused by exercise, poor posture or trauma.

How the shoulder works:

When the shoulder moves, all four joints make up the shoulder move. 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 support. The muscles of the rotator cuff are especially important in maintaining its stability. A lot of muscles that help move the shoulder connect to the neck as well. This means decreased flexibility in the shoulder can affect the neck, and vice versa.

Main shoulder joints:

  • Glenohumeral (GH) joint
  • Acromioclavicular joint
  • Scapulothoracic joint
  • Sternoclavicular joint

Major muscles and functions of the shoulder:

  • Flexion: anterior deltoid, biceps and serratus anterior
  • Extension: posterior deltoid, triceps and latissimus dorsi
  • Abduction: anterior/lateral deltoid and supraspinatus
  • Adduction: latissimus dorsi, subscapularis and teres major
  • External rotation: infraspinatus and teres minor
  • Internal rotation: subscapularis, latissimus dorsi and teres major


Created by: Missy Albrecht DPT, CSCS, FMS