Step 1 topics → Musculoskeletal, Skin, and Connective Tissue → Rotator Cuff Injury and Tear

Rotator Cuff Injury and Tear

USMLE Step 1 trap: Incorrectly includes the biceps tendon as a rotator cuff component instead of recognizing SITS muscles only. The rotator cuff consists of Supraspinatus, Infraspinatus, Teres minor, and Subscapularis (SITS); the biceps is not a rotator cuff muscle.

Rotator cuff injuries are a classic USMLE Step 1 musculoskeletal topic that shows up in clinical vignettes involving shoulder pain, weakness, or trauma. The rotator cuff is made up of four muscles — Supraspinatus, Infraspinatus, Teres minor, and Subscapularis (SITS) — and the exam expects you to know their anatomy cold: what each muscle does, which nerve supplies it, and which muscle tears most often. Supraspinatus tears are by far the most tested scenario because the supraspinatus passes through a narrow subacromial space, making it vulnerable to impingement and degeneration at its insertion on the greater tuberosity.

The exam tests this concept from multiple angles. Pure recall questions ask you to identify SITS muscles or match innervation. Application questions give you a clinical vignette — a 55-year-old with shoulder pain on abduction, or a baseball pitcher who can't hold their arm up — and ask which muscle is injured or which physical exam test confirms it. Passage-based questions may describe a physical exam finding and ask you to interpret what it means diagnostically. The physical exam tests are a high-yield trap: students often confuse which test diagnoses what, or assume a positive impingement sign means there's a confirmed tear.

What makes this topic tricky is that several tests sound interchangeable but are not. The empty-can (Jobe) test isolates the supraspinatus. The drop-arm test suggests a large or complete tear. Neer and Hawkins-Kennedy are impingement signs — they do NOT confirm a tear, and Step 1 may specifically test whether you know that MRI is required for that. Students also routinely miscategorize the biceps tendon as part of the rotator cuff, which is a classic distractor in anatomy-style questions.

From real student decks
65%have cards covering this topic
43%have mature cards

Common misconceptions

Common mistake
Wrong: The biceps tendon is part of the rotator cuff.
Right: The rotator cuff consists of Supraspinatus, Infraspinatus, Teres minor, and Subscapularis (SITS); the biceps is not a rotator cuff muscle.
The biceps has a long head tendon that runs through the bicipital groove and can be a source of shoulder pain, which is probably why students conflate it with the rotator cuff. But the rotator cuff is defined strictly by the SITS muscles — Supraspinatus, Infraspinatus, Teres minor, Subscapularis. These four muscles form a cuff around the glenohumeral joint and stabilize the humeral head. The biceps is a flexor and supinator of the forearm, supplied by the musculocutaneous nerve — an entirely different structure.
Common mistake
Wrong: Infraspinatus tears are the most common rotator cuff injury because it is the largest muscle.
Right: Supraspinatus tears are the most common rotator cuff injury, typically occurring at its insertion on the greater tuberosity.
Infraspinatus is not the most commonly torn muscle just because it's large. The supraspinatus is the most frequently injured because it runs through the tight subacromial space between the acromion and the humeral head, making it uniquely prone to impingement, compression, and eventual tearing — especially at its distal insertion on the greater tuberosity. This is a watershed area with poor blood supply, accelerating degeneration.
Common mistake
Wrong: The drop-arm test specifically isolates supraspinatus tears.
Right: The empty-can (Jobe) test is most specific for supraspinatus tears; the drop-arm test indicates a large or complete rotator cuff tear but is less specific for supraspinatus alone.
Both the empty-can and drop-arm tests are used in rotator cuff evaluation, but they test different things. The empty-can (Jobe) test has the patient hold their arm at 90° of abduction in the plane of the scapula with the thumb pointing down (like emptying a can), and pain or weakness specifically implicates the supraspinatus. The drop-arm test — where the patient can't slowly lower an abducted arm — suggests a large or complete tear of the rotator cuff overall, but it's less specific for the supraspinatus alone.
Common mistake
Wrong: Neer and Hawkins-Kennedy tests diagnose rotator cuff tears directly.
Right: Neer and Hawkins-Kennedy tests are impingement signs that suggest subacromial impingement syndrome, not definitive rotator cuff tears; MRI is needed to confirm a tear.
Neer and Hawkins-Kennedy tests provoke pain by mechanically compressing the supraspinatus tendon under the acromion — they are impingement signs, not tear-confirmation tests. A positive Neer (passive forward flexion reproducing pain) or Hawkins-Kennedy (internal rotation at 90° flexion reproducing pain) tells you the patient likely has subacromial impingement syndrome, but you cannot distinguish impingement from an actual structural tear based on these tests alone. On USMLE Step 1, if a vignette asks what confirms a rotator cuff tear, the answer is MRI, not these clinical tests.
Free Deck audit

See if your Anki deck covers this topic.

Upload your deck →
Guided session

Stuck on this? An AI tutor that probes your understanding.

Start a session →

What the exam tests

  1. Identify the four SITS muscles by name, their primary actions (e.g., supraspinatus initiates abduction 0–15°, infraspinatus and teres minor externally rotate, subscapularis internally rotates), and their nerve supplies (suprascapular nerve for supraspinatus and infraspinatus, axillary nerve for teres minor, upper and lower subscapular nerves for subscapularis).
  2. Recognize that supraspinatus tears are the most common rotator cuff injury, typically occurring at the tendon's insertion on the greater tuberosity of the humerus, often from chronic impingement or acute trauma.
  3. Match specific physical exam tests to what they detect: the empty-can (Jobe) test isolates supraspinatus integrity, the drop-arm test indicates a large or complete rotator cuff tear, and the Neer and Hawkins-Kennedy tests are signs of subacromial impingement — not confirmatory for tears.
  4. Determine when to manage conservatively (rest, NSAIDs, physical therapy for partial tears or impingement) versus when to pursue surgical repair (complete tears, failed conservative management, young active patients).

Can you avoid these mistakes?

A 60-year-old man presents with shoulder pain and weakness when raising his arm above his head. On exam, he cannot maintain his arm at 90° abduction with the thumb pointing down against resistance. Which muscle is most likely injured, at which specific anatomical site, and what nerve supplies it?
A vignette describes a patient with a positive Hawkins-Kennedy test and a positive Neer sign. A student says this confirms a rotator cuff tear and recommends surgery. What is wrong with this reasoning, and what is the next best step to confirm the diagnosis?
Which of the following is NOT part of the rotator cuff: supraspinatus, infraspinatus, subscapularis, biceps brachii (long head), teres minor? For the incorrect option, explain why it's a common source of confusion.
A 35-year-old athlete sustains a complete supraspinatus tear confirmed by MRI. Conservative management has failed after 3 months. What is the appropriate next step, and how does this differ from management of subacromial impingement without a confirmed tear?

Related topics

Bone Cells and Matrix Endochondral vs Membranous Ossification Fracture Healing Stages Compartment Syndrome

See how your Anki deck covers this topic.

Upload your deck for a free audit →