Shoulder impingement is a very common cause of shoulder pain, where a tendon (band of tissue) inside your shoulder rubs or catches on nearby tissue and bone as you lift your arm. Shoulder impingement occurs when the top outer edge of your shoulder blade, called the acromion, rubs against (“impinges on”) or pinches your rotator cuff beneath it, causing pain and irritation.
It affects the rotator cuff tendon, which is the rubbery tissue that connects the muscles around your shoulder joint to the top of your arm.
An impinging shoulder will often improve in a few weeks or months, especially with the right type of shoulder exercises, but occasionally it can be an ongoing problem.
Symptoms of shoulder impingement
Shoulder impingement can start suddenly or come on gradually.
Symptoms include:
- pain in the top and outer side of your shoulder
- pain that’s worse when you lift your arm, especially when you lift it above your head
- pain or aching at night, which can affect your sleep
- weakness in your arm
Your shoulder will not usually be stiff. If it is, you might have a frozen shoulder instead.