How to Understand Your Shoulder MRI Terms
Updated: 4 days ago
Shoulder MRI reports are full of medical words like "tendinosis," "labral tear," and "full-thickness tear." This guide explains the most common shoulder MRI terms in plain language, so you can understand your report and ask your doctor better questions. It is not a substitute for your doctor's explanation of your own results.
What is in a shoulder MRI report?
An MRI uses a strong magnet and radio waves, not X-rays, to make detailed pictures of the shoulder. It shows bones, tendons, muscles, cartilage, and fluid. A radiologist, a doctor trained to read medical images, studies the pictures and writes a report for your doctor.
Most reports have the same basic parts:
Exam: the body part and type of scan, such as "MRI right shoulder without contrast"
History or indication: why your doctor ordered the scan, such as shoulder pain after a fall
Technique: how the images were taken
Findings: a list of what the radiologist saw, structure by structure
Impression: a short summary of the most important findings
If you only read one part, read the impression. Then use the findings section and this guide to understand the details. For a general walk-through of report sections, see our guide on how to read your radiology report.
Common terms in shoulder MRI reports
Anatomy terms
Rotator cuff: A group of four muscles and their tendons that hold the ball of the upper arm in the shoulder socket and help you lift and turn your arm. The four tendons are the supraspinatus, infraspinatus, subscapularis, and teres minor.
Humeral head: The ball at the top of the upper arm bone (humerus).
Glenoid: The shallow socket on the shoulder blade where the humeral head sits.
Labrum: A ring of firm cartilage around the rim of the glenoid. It deepens the socket and helps keep the shoulder stable.
Bursa: A small, thin sac of fluid that lets tendons and bones glide past each other. The subacromial bursa sits above the rotator cuff.
Acromion: The bony tip at the top of the shoulder blade. It forms the roof over the rotator cuff.
AC joint (acromioclavicular joint): The joint where the collarbone meets the acromion at the top of the shoulder.
Biceps tendon: The long head of the biceps tendon runs through the front of the shoulder and attaches near the top of the labrum.
Descriptive terms
Tendinosis: Wear-and-tear changes inside a tendon, often from overuse or age. The tendon may look thicker or have a changed signal on MRI.
Tendinitis: Irritation or inflammation of a tendon. Many reports now use "tendinosis" or "tendinopathy" because long-term tendon problems often involve wear more than inflammation.
Tendinopathy: A general word for a tendon problem. It can include tendinosis and tendinitis.
Bursitis: Irritation of a bursa. On MRI, it often shows up as extra fluid in the bursa.
Impingement: Pinching of the rotator cuff tendons or bursa between bones when you lift your arm. MRI can show findings linked to impingement, but impingement is mainly diagnosed by your doctor's exam.
Edema: Extra fluid in a tissue. It can be a sign of injury or irritation.
Signal: How bright or dark a tissue looks on the images. "Increased signal" in a tendon may point to wear or a tear.
Common shoulder conditions on MRI
Rotator cuff tear
A rotator cuff tear is a tear in one or more of the rotator cuff tendons. The supraspinatus tendon is torn most often. The report may describe:
Partial-thickness tear: the tear goes only part of the way through the tendon
Full-thickness tear: the tear goes all the way through the tendon, from top to bottom
Size: how big the tear is, often in centimeters or millimeters
Location: which tendon and which part of it is torn
Retraction: how far the torn end has pulled back from where it attaches to bone
Muscle atrophy or fatty change: shrinking of the muscle or fat building up in it, which can happen with longer-standing tears
These details help your doctor decide on treatment options. Learn more in our article on MRI for rotator cuff injury.
Labral tear
A labral tear is a tear in the ring of cartilage around the socket. It can happen with a dislocation, a fall on an outstretched arm, or repeated overhead motion. Reports may use special names:
SLAP tear: "superior labrum, anterior to posterior." It is a tear at the top of the labrum, near where the biceps tendon attaches.
Bankart lesion: a tear of the lower front labrum, often linked to the shoulder slipping out of place toward the front.
Hill-Sachs lesion: a dent in the back of the humeral head that can happen when the shoulder dislocates.
Some labral tears are easier to see when contrast dye is placed into the joint before the scan. This is called an MR arthrogram. Your doctor decides if it is needed.
Arthritis
Arthritis in the shoulder means the smooth cartilage on the ends of the bones is wearing down. The report may mention cartilage thinning or loss, bone spurs (osteophytes), and fluid in the joint. Arthritis of the AC joint is a common finding, especially in older adults, and it does not always cause symptoms.
Adhesive capsulitis (frozen shoulder)
Frozen shoulder causes pain and stiffness. The joint capsule, the soft tissue that wraps around the joint, becomes thick and tight. On MRI, the radiologist may describe a thickened capsule or changes in the area near the front of the shoulder called the rotator interval. Frozen shoulder is diagnosed mainly by how the shoulder moves on exam; MRI findings help support it.
Measurement and severity terms
Partial-thickness vs. full-thickness: These describe how deep a tendon tear goes. A full-thickness tear goes completely through the tendon.
Retraction: How far a torn tendon has pulled back. The report may give this in centimeters.
Effusion: More fluid than normal inside the joint. A small amount of fluid is normal. More fluid can come with injury or irritation.
Mild, moderate, severe: Words radiologists use to describe how much change they see. These words describe the images, not how much pain you should have.
Words that sound scary but may be common
Some findings show up often, even in people without shoulder pain, especially as we age. These include mild tendinosis, small amounts of bursal fluid, and AC joint arthritis. A finding on the report does not always explain your symptoms. Your doctor puts the MRI together with your exam, history, and other tests.
The report may also include phrases like "clinical correlation recommended." This simply means the radiologist wants your doctor to compare the images with your symptoms and exam. It is a normal phrase and is not a warning on its own. For more phrases like this, see our patient guide to decoding the language of MRI reports.
How to use this information
Understanding the words in your report can make your follow-up visit more useful. Before your appointment:
Read the impression section first and circle any terms you don't know
Write down questions, such as "Is this tear partial or full-thickness?"
Ask how the findings match your symptoms
Ask what the next steps are and what your options might be
Only your doctor can tell you what your results mean for you and what treatment fits your situation.
Frequently asked questions
What does a partial-thickness rotator cuff tear mean?
It means the tendon is torn part of the way through but is not torn completely. Your doctor will explain what this means for you and discuss treatment options based on your symptoms and exam.
Is tendinosis the same as tendinitis?
Not exactly. Tendinosis means wear-and-tear changes inside the tendon. Tendinitis means irritation or inflammation. Some reports use "tendinopathy" as a general word that covers both.
How does bursitis show up on an MRI?
Bursitis often shows up as extra fluid in the bursa. Fluid looks bright on certain MRI images, which helps the radiologist spot it.
What does tendon retraction mean?
Retraction means the torn end of a tendon has pulled back from where it attaches to the bone. The report may list how far it has pulled back. Ask your doctor how this affects your options.
Can an MRI show every shoulder problem?
MRI shows many shoulder problems very well, especially in soft tissues. But some conditions are diagnosed mainly by exam, and some need other tests. Your doctor decides which tests you need.
Who can explain my shoulder MRI results?
The doctor who ordered your MRI is the best person to explain your results. They know your history and can tell you what the findings mean for you.
Related reading
Schedule an MRI at Millenium MRI
If your doctor has ordered a shoulder MRI, Millenium MRI can help. Our scans are read by board-certified radiologists and performed by ARRT-certified technologists. Results are usually sent to your referring doctor within 24 hours, and same-day appointments are often available. We accept most insurance plans, workers' compensation, personal injury cases, and self-pay. We have centers in Ocala, Largo, and Tamarac, Florida, and in North Little Rock, Springdale, Jonesboro, and Marion, Arkansas, open Monday through Friday, 9am to 5pm.
This article is for general information and is not medical advice. Talk with your doctor about your specific situation.
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