Which muscles are included in the upper extremity muscle testing of the MRC-SS?

• A. Shoulder adduction; Elbow extension; Finger flexion
• B. Shoulder abduction; Elbow flexion; Wrist extension
• C. Shoulder external rotation; Elbow supination; Wrist flexion
• D. Shoulder flexion; Elbow extension; Wrist deviation

Answer: (B)

The upper extremity portion of the MRC-SS focuses on three movements that reliably reflect proximal to mid-upper-limb strength in patients who may be difficult to test. Shoulder abduction checks the deltoid (a key proximal mover), elbow flexion assesses the biceps, and wrist extension tests the extensor muscles of the forearm. Together, these target common sites of weakness and map well to standard testing protocols, providing a clear, repeatable way to gauge overall upper-limb strength in ICU patients.

Other movements like adduction, elbow extension, wrist flexion, or finer finger actions are not part of this specific upper-extremity testing set because they can be more variable to assess in a supine, weak patient or require finer motor control and coordination that may confound the strength score. Therefore, the three movements used are shoulder abduction, elbow flexion, and wrist extension.