By: Sara Stites, DPT, ATC
The scapula or “shoulder blade” is a large flat triangle shaped bone that sits on the back of our rib cage. While the scapula has only one bony attachment to the body at the clavicle, it has over 18 muscular attachments. The scapula also forms the shallow socket that our humerus or upper arm bone sits in. Proper positioning of the scapula is important in normal shoulder motion and function, especially in overhead athletes. When there is weakness or muscular imbalance around the scapula it can cause issues that may lead to shoulder and upper extremity injuries and postural dysfunction. The acronym SICK (Scapular malposition, Inferior medial border prominence, Coracoid pain/malposition, disKinesis of movement). “Dys”- alteration of “kinesis”- motion, means loss of normal control of the scapular motion. There are three different types of scapular dyskinesis.
Type I- Prominence of the inferior medial scapular border
Type II- Prominence of the entire medial scapular border
Type III- Superior translation of the entire scapula and prominence of the superior medial scapular border
There can be multiple causes of scapular dyskinesis. They can be grouped into bony causes, joint causes, neurologic causes, and/or soft tissue causes. Bony causes can include thoracic kyphosis, clavicle fracture, or scapular fracture. Joint causes can be AC (acromioclavicular) or shoulder joint instability. Neurological causes can include cervical radiculopathy or nerve palsy. Soft tissue causes typically involve muscle inflexibility and stiffness and decreased muscular control. Risk factors for having or developing scapular dyskinesis include:
- Intense or repetitive overhead activity
- Overuse and fatigue
- Direct trauma
- Muscle strain
- Muscular imbalance
Scapular dyskinesis can be painful by itself, or it can be a contributing factor in other upper extremity injuries including shoulder impingement, shoulder labral injuries, shoulder instability, and/or increase stress on the elbow. These types of injuries are common in swimmers, overhead athletes, and throwing athletes. Recognizing and treating scapular dyskinesis in these athletes is important to both help prevent other upper extremity injuries and also improve scapular motion and control to keep injures from returning. Physical therapy can help to address scapular dyskinesis by evaluating the athlete and determining the cause of the dyskinesis. Once the cause of the dyskinesis is determined physical therapy will work on restoring normal scapular function for optimal shoulder and scapular mobility and stability. Proper scapular mobility, stability, and control is important in everyday function of the shoulder, and especially important for overhead athletes.
Kibler et al. Clinical implicatins of scapular dyskinesis in shoulder injury: the 2013 consensus statement from the scapular summit. Br J Sports Med 2013 47: 877-885.