What is the main effect of an injury to the subscapularis muscle?

What is the main effect of an injury to the subscapularis muscle?

• A. Weakness during external rotation
• B. Deficit in internal rotation
• C. Pain during abduction
• D. Accumulation of ALA

Answer: (B)

Injury to the subscapularis muscle primarily affects its function as a powerful internal rotator of the shoulder. The main role of this muscle is to facilitate movements that rotate the arm toward the body. Therefore, if there is an injury to the subscapularis, there would be a notable deficit in internal rotation. This means that the affected individual would struggle to perform activities that require the arm to be rotated inward, such as reaching behind the back or moving the arm across the body. Understanding the function of the subscapularis muscle clarifies why options focused on external rotation or abduction are not the main effects of its injury. Those movements involve different muscles, such as the teres minor and infraspinatus for external rotation or the deltoid for abduction. Additionally, the mention of ALA, or aminolevulinic acid, does not relate to the shoulder muscles and is not relevant to the injury or its consequences in this context. Therefore, the experience of a deficit in internal rotation due to injury to the subscapularis is indeed the most accurate assessment.

Injury to the subscapularis muscle primarily affects its function as a powerful internal rotator of the shoulder. The main role of this muscle is to facilitate movements that rotate the arm toward the body. Therefore, if there is an injury to the subscapularis, there would be a notable deficit in internal rotation. This means that the affected individual would struggle to perform activities that require the arm to be rotated inward, such as reaching behind the back or moving the arm across the body.

Understanding the function of the subscapularis muscle clarifies why options focused on external rotation or abduction are not the main effects of its injury. Those movements involve different muscles, such as the teres minor and infraspinatus for external rotation or the deltoid for abduction. Additionally, the mention of ALA, or aminolevulinic acid, does not relate to the shoulder muscles and is not relevant to the injury or its consequences in this context. Therefore, the experience of a deficit in internal rotation due to injury to the subscapularis is indeed the most accurate assessment.