The scapula bone plays an integral role in the optimal functioning of the shoulder joint. Scapular dyskinesis refers to an altered motion or position of the scapula.The scapula in anatomy, also known as shoulder bone, connects the upper arm bone (the humerus) with the collar bone (the clavicle). It has many different roles for the proper function of the shoulder. It provides synchronus scapular rotation for humeral movements; it acts as a link in the kinetic chain, and it serves as a base for the activation of the rotator cuff. All these roles play an important part in the functioning of the arms. If there is any injury, weakness of the muscles, or inflexibility, the proper functioning of the scapula is compromised such that movement and/or the position of the scapula can be altered. Scapular dyskinesis is the scientific term used in relating to a dysfunction of the scapula either from movement or of the position.
Types of scapular dyskinesis
Three different types of scapular dyskinesis are known but there is overlap between the three types.
• Infero –medial scapula border prominence– this type is associated with the tightness of the anterior side of the shoulder and weakness of the lower trapezius and that of the anterior muscles of the serratus. The posterior tipping of the scapula narrows the subacromial space when performing overhead motion resulting to pain in the externally rotated position.
• Medial border prominence – this type occurs due to fatigue of the scapula stabilising muscles and results in the winging of the entire medial border of the scapula at rest. It is a lot more evident in the cocking position and after repetitive elevation of the upper extremities.
• Supero-medial border prominence – this type is associated with impingement and rotator scuff injury. It is displayed as a prominence of the superior medial border of the scapula.
What causes scapular dyskinesis?
This is a really interesting question? Certainly overhead athletes (tennis players, pitchers and swimmers) are at risk of this condition and scapular dyskinesis can prematurely end promising sports careers and as such is of much interest. However the consensus statement from an international conference dedicated just to scapular dyskinesis in 2012 questioned whether scapular dyskinesis causes shoulder injuries or is itself a compensatory response to an existing injury.
How does it present?
Scapular dyskinesis can present with shoulder pain, limitation of movement, impingement or impaired functionality of the shoulder joint. As astute observer can notice the dyskinesis while watching the patient perform a range of shoulder movements. This condition can also be asymptomatic.
How is it diagnosed?
This condition is diagnosed from history and clinical examination of the shoulder in a variety of positions which is based on a well established protocol.
Radiological imaging of the shoulder is usually required to rule out any causative factors.
How is scapular dyskinesis managed?
As in any medical condition, it is essential to carefully treat any associated diseases in order to re establish the normal anatomy of the shoulder joint.
This is then followed by a kinetic rehabilitation protocol to restore dynamic scapular stability.
