A 62 year old woman, has a 3 month history of increasing right shoulder pain. She is now unable to lift her arm to brush her hair or to take a can off a shelf. She denies any numbness or tingling or radiation of the pain down her arm. On physical examination, she exhibits weakness in abduction and external rotation or her right arm. Her shoulder shows a normal passive range of motion. When asked to hold her arms abducted to 90 degrees, she is unable to do so on the right. There is no motor weakness in her forearm or hand. Her right upper extremity has normal pulses and normal sensation. Which of the following muscles make up the injured structure?
A 62 year old woman, has a 3 month history of increasing right shoulder pain. She is now unable to lift her arm to brush her hair or to take a can off a shelf. She denies any numbness or tingling or radiation of the pain down her arm. On physical examination, she exhibits weakness in abduction and external rotation or her right arm. Her shoulder shows a normal passive range of motion. When asked to hold her arms abducted to 90 degrees, she is unable to do so on the right. There is no motor weakness in her forearm or hand. Her right upper extremity has normal pulses and normal sensation. Which of the following muscles make up the injured structure?
💡 Explanation
**Core Concept**
The patient's symptoms suggest a condition affecting the muscles around the shoulder joint, specifically those involved in abduction and external rotation. This points towards an issue with the **rotator cuff**, a group of muscles and tendons that stabilize the shoulder joint.
**Why the Correct Answer is Right**
The rotator cuff is composed of four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles work together to provide stability and mobility to the shoulder joint. The patient's inability to abduct her arm (lift it out to the side) and perform external rotation suggests damage to one or more of these muscles, particularly the supraspinatus, which is primarily responsible for arm abduction.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the muscles involved in the rotator cuff.
**Option B:** Incorrect as it might refer to a different set of muscles or tendons not primarily involved in the symptoms described.
**Option C:** Incorrect because, although it could be related to shoulder function, it does not accurately represent the muscles of the rotator cuff.
**Option D:** Incorrect as it is not the correct combination of muscles that make up the injured structure described in the scenario.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the rotator cuff muscles, especially the supraspinatus, are prone to injury and degeneration with age, leading to symptoms like those described. Early diagnosis and treatment can prevent further deterioration and improve outcomes.
**Correct Answer:** Correct Answer: D. Supraspinatus, infraspinatus, teres minor, and subscapularis.
✓ Correct Answer: D. Supraspinatus, infraspinatus, teres minor, subscapularis
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