Anatomy Exam Muscles of the Rotator Cuff 5

Question 1

Which rotator cuff muscle is most commonly torn in rotator cuff injuries?

Accepted Answer

Supraspinatus

Answer

The supraspinatus is the most commonly torn rotator cuff muscle, typically at its insertion on the greater tubercle.

Question 2

The 'drop arm test' is positive when a patient cannot slowly lower the arm from 90° abduction. This indicates injury to which structure?

Accepted Answer

Supraspinatus tendon

Answer

A positive drop arm test indicates a complete supraspinatus tear, as the muscle cannot control the eccentric lowering of the arm.

Question 3

From which cord of the brachial plexus does the upper subscapular nerve originate?

Accepted Answer

Posterior cord

Answer

The upper subscapular nerve originates from the posterior cord (C5, C6) of the brachial plexus.

Question 4

Which of the following clinical tests is most specific for infraspinatus and teres minor pathology?

Accepted Answer

External rotation lag sign

Answer

The external rotation lag sign tests external rotation strength, isolating the infraspinatus and teres minor.

Question 5

The interval between the supraspinatus and subscapularis tendons is called the rotator interval. What structure passes through this interval?

Accepted Answer

Long head of the biceps tendon

Answer

The long head of the biceps tendon passes through the rotator interval before entering the bicipital groove.

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