Subacromial bursitis means the small fluid sac on top of your rotator cuff is irritated and thickened. It usually causes pain at the front and outer shoulder, worse lifting the arm out to the side and at night.
Most people get better with exercise, activity changes and time. Improvement usually shows within FOUR weeks, more within twelve, and full recovery can take up to a year.
One thing to know: a “bursitis” finding on a scan is VERY common in people with no pain at all. It’s often part of a wider rotator cuff problem rather than the whole story.
What the bursa is
- A thin, fluid-filled sac sitting in the narrow space between the bony tip of your shoulder and the rotator cuff tendon below it
- Its job is to let the tendon glide smoothly as you lift your arm
- It has lots of nerve endings, so when it’s irritated, it can genuinely hurt
What your scan result means
- In one study of men aged 40 to 70 with NO shoulder pain, about 8 in 10 had a thickened bursa on MRI
- So the finding is real, but common. It doesn’t prove the bursa is what hurts
- Bursa and cuff problems usually come together. Many UK physio services now treat them as one condition: subacromial or rotator cuff-related shoulder pain
- There’s no agreed “cut-off” thickness on ultrasound that confirms bursitis
Bursitis on a scan is a finding. It isn’t always the reason you hurt.
Symptoms
- Pain at the front and outer shoulder, staying in the shoulder rather than shooting down the arm
- Pain lifting the arm out to the side, especially past shoulder height
- Tender just below the bony point of the shoulder
- Night pain, especially lying on that side
- Often after a fall, a burst of overhead work, or repetitive lifting
What it’s NOT
- Not frozen shoulder: with bursitis, someone else can usually move your arm fully. With frozen shoulder, nobody can. See frozen shoulder
- Not a big cuff tear: with bursitis, strength is usually normal once you get past the pain. See rotator cuff tear
What helps
- Exercise: the best-supported treatment. Strengthening for the rotator cuff and shoulder blade muscles, three to four times a week, with a day’s rest between sessions
- The pain rule: some discomfort during exercise is fine. It should settle within a few hours, not linger into the next day
- Change what flares it: less overhead work for a while, keep things you carry close to your body
- A steroid injection: can give short-term relief to help you exercise. The benefit is usually modest and fades
- Anti-inflammatory tablets: in the studies, about as helpful as an injection for this kind of shoulder pain
What about surgery?
- The operation for this area shaves bone and removes the bursa
- In a large trial, it did no better than a FAKE operation, where the surgeon only looked inside
- So surgery is rarely the answer for bursitis on its own. See shoulder impingement
The two versions that are different
- Infected bursitis: rare, but serious. The bursa sits deep, so there’s often NO fever, redness or warmth. Pain and swelling that get worse, especially in the days or weeks after an injection, need a same-day check. Diabetes and a weak immune system raise the risk
- Calcium in the bursa: calcium deposits in the tendon can burst into the bursa. The pain goes from annoying to unbearable over a day or two. It needs different treatment, so get it seen
Go today if
- Your shoulder is getting WORSE, not better, in the days or weeks after a steroid injection
- You feel unwell, with or without a fever, and your shoulder is increasingly painful
- Pain has suddenly become severe over a day or two
- You fell and suddenly can’t lift the arm
Get it checked if
- No improvement after 4 to 6 weeks of exercise and activity changes
- Night pain is stopping you sleeping
- The arm feels weak, not just painful
Common on scans, usually settles with exercise, and only an emergency when it’s infected.