Sub-Acromial Impingement Syndrome
The shoulder is a complex joint, composed of the humerus (upper arm bone), the clavicle (collar bone), and the scapula (shoulder blade). Each of these can joints can be a source of pain as can the surrounding structures including the muscles, tendons, nerves, ligaments, bursae and the joint capsule.
Due to the shoulder’s high degree of movement, in a variety of directions, it is an inherently unstable joint that is prone to problems associated with hypermobility. In today’s blog we will be discussing a particularly common shoulder pathology known as sub-acromial impingement or sub-acromial Pain Syndrome (SAPS).
SAPS is a clinical syndrome which is very common in swimmers. It occurs when the tendons of the small shoulder muscles (most commonly the biceps and supraspinatus) and/or the burse that sits on top of these tendons become pinched as they pass through a space underneath the acromion (bony part on top of the shoulder). This area is known as the sub acromial space and is formed by the coracoacromial arch, Acromioclavicular joint and the acromion.
Impingment is cause by a reduction in the size of the sub acromial space which reduces the area for the structures to move without impedment. This can occur if something grows into the space or if the structures running through the space get larger. There are two main types of impingement:
1. Primary external impingement: Caused by abnormalities to the surrounding structures (usually bony) that encroach into the sub-acromial space from above. These may be congenital abnormalities, such as an abnormal hook or beak, or can be due to the formation of a bone spur (osteophyte) into the space which reduces the area for the structures to move.
2. Secondary external impingement: Encroachment of the sub-acromial space, from above, due to suboptimal muscular stabilisation/activation of the muscles surrounding the scapula and or excessive tightness of surrounding musculature through the chest, which alters the position of the scapula. I.e. poor posture which causes a forward and downward movement of the acromion and closes off the space.
Excessive overhead movement or activity with the arm can also force the tendons in the area to be squeezed between the humeral head and the acromion causing repetitive pinching and subsequent impingement symptoms.
It can often be difficult to pinpoint the precise structure being impinged due to the closeness of structures however, the supraspinatus tendon, biceps tendon and sub-acromial bursa are the 3 most common structures involved.
Repetitive impingement of the structures causes irritation and inflammation. This causes swelling and an increase in the size of the tendons which further reduces the space for them to run and increases the risk of recurrent impingement.
Impingement syndrome results in pain, weakness and a decrease in shoulder range of movement. Pain is exacerbated by overhead movement of the arm and a painful arc may be present during elevation of the arm from 60° to 120°.
Pain can also be referred down the arm as a result of pain and trigger points in the supraspinatus muscle.
The good news is that Sub-acromial Impingement syndrome is one of the more common shoulder problems we see in the clinic and is readily treatable, however the longer it is left untreated the more debilitating it usually becomes and the longer it takes to improve.
Following an accurate diagnosis, which includes several special tests to confirm the presence of impingement, treatment consists of deep tissue release and dry needling to the muscles involved, mobilisation of the surrounding joints in the shoulder, neck and thoracic spine as well as a graduated stretching and strengthening program to balance the scapula and unload the structures being impinged.
Prevention is always better than cure, especially in the case of impingement syndrome so 3 tips to help minimise the risk of developing sub-acromial pain are:
1. Practice good posture by making sure your work environment is ergonomically sound
2. Engage in regular foam rolling for the middle of your back (thoracic spine)
3. Engage in regular back strengthening exercises and pectoral stretches to hold your shoulders in the most balanced position.
4. Avoid excessive repetitive overhead exercises in a short period of time
So that’s a brief overview of how sub-acromial pain syndrome problems can occur, If you have questions or comments feel free to e-mail us at firstname.lastname@example.org and we will be happy to answer them for you.
If you think you may already be suffering from sub-acromial pain, then addressing it sooner rather than later is crucial. So, if you want relief now, call us on (08) 9486 8653 and we will arrange an appointment for you.