Shoulder Impingement: Causes of Subacromial Impingement Syndrome
Learn about Subacromial Impingement Syndrome (SIS), a common cause of shoulder pain where the supraspinatus tendon and bursa become pinched in a crowded space.
Best quote from Shoulder Impingement: Causes of Subacromial Impingement Syndrome
Subacromial impingement is a 'crowded house' situation where the focus must shift from just strengthening a tendon to integrated shoulder mechanics. You can create more room through better mechanics, stronger stabilizers, and smarter movement patterns rather than relying on surgery.
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Teaching on assessment, testing, investigation, diagnosis and physiotherapy treatment of shoulder impingement syndrome
Frequently Asked Questions
Subacromial Impingement Syndrome, or SIS, is a progressive orthopedic condition characterized by a "crowded house" effect within the shoulder. It occurs when the tiny subacromial space, typically only 1 to 1.5 centimeters high, narrows and pinches structures like the supraspinatus tendon, the bursa, and the long head of the biceps. This syndrome is a leading cause of shoulder pain, accounting for approximately 44% to 65% of clinical shoulder complaints.
Shoulder impingement is often caused by a lack of space within the subacromial area, which can be due to an individual's physical anatomy or specific movement patterns. While many associate it with bone spurs, it is actually a dynamic clinical syndrome that overlaps with rotator cuff-related pain. When the space narrows, the internal tendons and bursa are squashed, leading to symptoms that can progress from simple swelling to more serious tissue damage.
According to the Neer stages of this orthopedic condition, the syndrome is progressive. It typically begins as Stage I, which involves reversible edema or swelling within the shoulder tissues. If the impingement continues without intervention, it can lead to Stage II and beyond, resulting in more permanent changes such as fibrosis, tendinosis, and eventually full-blown rotator cuff tears as the tendons and bursa remain chronically pinched.
In a crowded subacromial space, several key structures are at risk of being pinched or squashed. These include the supraspinatus tendon, the subacromial bursa, and the long head of the biceps tendon. Because these tissues must all function within a very narrow gap of about 1 to 1.5 centimeters, any reduction in space due to inflammation or structural issues can lead to the cluster of symptoms known as Subacromial Impingement Syndrome.
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From Columbia University alumni built in San Francisco
BeFreed Brings Together A Global Community Of Curious Minds
"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."
"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."
"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."
"Reading used to feel like a chore. Now it’s just part of my lifestyle."
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"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
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"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."
"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."
"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."
"Reading used to feel like a chore. Now it’s just part of my lifestyle."
"Feels effortless compared to reading. I’ve finished 6 books this month already."
"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."
"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"
"It is great for me to learn something from the book without reading it."
"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."
"Makes me feel smarter every time before going to work"
"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."
"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."
"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."
"Reading used to feel like a chore. Now it’s just part of my lifestyle."
"Feels effortless compared to reading. I’ve finished 6 books this month already."
"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."
"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"
"It is great for me to learn something from the book without reading it."
"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."
"Makes me feel smarter every time before going to work"
