What happens when the suprascapular nerve is entrapped at the suprascapular notch?

• A. Weakness of the infraspinatus only
• B. Atrophy of both supraspinatus and infraspinatus
• C. Pain without muscle atrophy
• D. Weakness of the teres minor only

Answer: (B)

When the suprascapular nerve is entrapped at the suprascapular notch, it leads to atrophy of both the supraspinatus and infraspinatus muscles. The suprascapular nerve innervates these two muscles, which play critical roles in shoulder abduction and external rotation, respectively.

As the nerve is compromised due to entrapment, both of these muscles are affected. This atrophy can manifest as weakness in shoulder movements, particularly abduction (due to supraspinatus involvement) and external rotation (due to infraspinatus involvement). Additionally, because the suprascapular nerve is specifically responsible for providing motor innervation to these muscles, a loss of function leads to visible atrophy over time, which can be observed through clinical examination and imaging.

In contrast, options suggesting weakness or atrophy limited to only one of the muscles do not account for the shared innervation and subsequent effects of nerve compression. Similarly, the assertion of pain without muscle atrophy overlooks the primary functional consequence of nerve entrapment, which typically includes motor deficits and muscle wasting. Thus, the correct understanding of suprascapular nerve entrapment highlights the impact on both the supraspinatus and infraspin