Rotator Cuff Tears: What Your MRI Shows

Medically reviewed by M. Brett Raynor, M.D., board-certified orthopaedic sports medicine surgeon. Updated October 2026.

An MRI shows your shoulder in slices, and on the kind of picture I look at, a healthy rotator cuff tendon is a dark band that runs all the way down to the bone, while fluid shows up bright. Tendinitis makes the tendon thicker and grayer, and bursitis fills the sac above it with fluid; that is irritated, not torn. A partial-thickness tear goes only part of the way through the tendon, on the underside or the top side. A full-thickness tear goes all the way through, usually where the tendon attaches to the bone, and it can be as small as a pinhole or as big as a gaping hole. When I read your MRI, I ask how big the tear is, how far it has pulled back, how healthy the muscle is, and whether it came from an injury or wore out over time.

 

In this video

  • 0:00 The shoulder and the rotator cuff
  • 0:18 How an MRI shows the shoulder in slices
  • 0:28 A healthy tendon on MRI
  • 0:40 Tendinitis and bursitis
  • 0:51 Partial-thickness tears: underside and top side
  • 1:08 Full-thickness tears: a pinhole or a big hole
  • 1:24 A retracted (pulled back) tendon
  • 1:39 The muscle: shrinking and fat
  • 2:04 What I look for on your MRI
  • 2:19 Two kinds of tears: wear over time or an injury
  • 2:40 An MRI doesn't show pain
  • 2:52 Bring your MRI

Common questions

What is the difference between a partial-thickness and a full-thickness rotator cuff tear?

A partial-thickness tear only goes part of the way through the tendon, either on the underside, the side facing the joint, or on the top side, under the bursa. It's damaged, but it hasn't gone all the way through. A full-thickness tear goes all the way through the tendon, usually where the tendon attaches to the bone. A little pinhole in your jeans is a full-thickness tear, and so is a big gaping hole, so the same words can describe two very different tears.

What does a retracted rotator cuff tear mean on MRI?

When the tendon tears away from the bone, it can pull back toward the socket, because the muscle pulls it that way. On the MRI you can see the muscle turning into tendon, but the tendon stops short of where it is supposed to reach on the bone. How far it has pulled back is one of the things I look at when deciding whether it can be brought back out to the bone.

What does fat in the rotator cuff muscle mean?

When a tendon has been torn for a long time, the muscle behind it shrinks and turns to fat, and once that happens it usually doesn't come back, even after a good repair. It also helps me judge whether a tear has been there a long time, even if you didn't know about it.

If my MRI shows a rotator cuff tear, does that mean it's causing my pain?

Not necessarily. An MRI doesn't show pain, and lots of people have tears and no pain at all. In one study, more than half of people over sixty with no shoulder pain had a rotator cuff tear on MRI (Sher JS, et al. J Bone Joint Surg Am. 1995;77:10-15). Your exam and how your shoulder feels matter just as much as the picture.

Does every rotator cuff tear need surgery?

No. Tears that wear in over time and get irritated don't always need an operation. But when someone with a normal shoulder falls and can't lift their arm, that acute tear from an injury is one we usually fix sooner rather than later.

Full transcript

The shoulder is a ball and socket joint. The rotator cuff are four tendons, deep down inside, that help start motion. One up top, one in the front, and two around the back. An MRI takes pictures of your shoulder in slices, kind of like slices of bread. Most of what I look at is a slice like this, straight through the top tendon. On this kind of picture, a healthy tendon is dark, a nice black band all the way down to where it attaches to the bone. Fluid shows up as bright on this sequence. When the tendon is irritated, it gets a little thicker and grayer, and the little balloon sac above it, the bursa, can fill up with fluid. That's irritated, not torn, and that can calm down. A partial-thickness tear only goes part of the way through the tendon. This is on the underside, the side facing the joint. This one is on the top side, under the bursa. Either way, it's damaged, but it hasn't gone all the way through. A full-thickness tear goes all the way through the tendon, usually where the tendon attaches to the bone. A little pinhole in your jeans is a full-thickness tear. A big gaping hole in your jeans is a full-thickness tear. Same word, two very different things. When it tears away, it can pull back towards the socket, because the muscle pulls it that way. On your MRI, here's the muscle that turns into tendon, but it stops here, and it's supposed to reach all the way over here. The other thing I look at is the muscle. A healthy one fills up this space. When a tendon has been torn for a long time, the muscle behind it shrinks and turns to fat. And once that happens, it usually doesn't come back, even after a good repair. This is how we can judge whether or not the tear has maybe been there a long time, even without knowing it. So when I look at your MRI, I'm asking: How big is it? How far has it pulled back? How healthy is the muscle? And did it happen with an injury, or wear out over time? Can it reach, and will it heal? There are two types of tears: the kind that a lot of people have, that wears in over time and gets irritated, and then acute tears from an injury, where somebody had a normal shoulder, they fall, and they can't lift their arm. Those we usually fix sooner rather than later, whereas worn-in type of tears don't always need an operation. And an MRI doesn't show pain. Until somebody invents an MRI where pain shows up as green, your exam and how it feels matter just as much as the picture. Lots of people have tears and no pain at all. If you've got an MRI and you're not sure what it means, bring it in and we'll go through it together.

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This video and page are general education and are not a substitute for an evaluation of your own knee, shoulder or hip.

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