Do I Have an Unstable Shoulder?

Shoulder instability is a catch all term used to describe the inability of the body to keep the upper arm in the center of the shoulder joint. Misalignment of the shoulder joint can arise as different symptoms, but generally most complain of some sort of weakness during overhead activities.

The Shoulder Joint:

Quick anatomy class, the shoulder joint is made of the upper arm bone (Humerus) and the shoulder blade bone (scapula). Notice the connection point between the humerus and the scapula. The head of the humerus is pretty big compared to the connecting surface of the scapula. In order to keep the head of the humerus centered in on scapula surface, the ligaments, muscles and cartilage structures around the shoulder joint need to work together in coordination.

How does it happen:

Unstable shoulder can begin with a single traumatic event causing damage to the surrounding structures of the shoulder. In the sporting world, getting tackled from behind or the side with your arm reaching overhead can easily damage the ligaments of the shoulder leading to shoulder instability. If you fall with an outstretched arm directly onto your side, there is a big risk for injuring both cartilage and ligaments.

Unstable shoulder can also occur with repetitive extreme range motions. A classic example would be the baseball throw position. Due to the repetitive action of placing your shoulder in an extreme range of motion, the ligaments can get overstretched and muscles can be strained. Other notable activities with these extreme shoulder ranges include swimming, weight training and overhead related work like light fixture installation.

What does it feel like:

If the muscle, ligaments or cartilage around the shoulder is injured, there is a chance that the humerus will be off centered when moving your arm around, especially during overhead activity. Pain and/or weakness at the shoulder would be the most common complaint, especially when performing overhead activities like hanging clothes, reaching for high cupboards, catching ball overhead and overhand throws.

Shoulder instability can be debilitating to a point where it interferes with your hobbies. If left unchecked, it may start affecting your activities of daily living as well. Simple task like hanging clothes, reaching of high cupboards and every reaching across the table may become more and more difficult. Before it gets to this point, it’s probably a good idea to get it checked out by a physiotherapist.

Physiotherapist are movement specialist and can help manage shoulder conditions like shoulder instability. At Capital physiotherapy, we perform a thorough assessment to identify which structures of the shoulder has been compromise. This way, we can directly target the deficit to get the best results as efficient as possible. If your shoulder is giving you grief, email us at or give us a call at one of our clinics at South Yarra, Balwyn and Footscray to start a holistic tailored program.