Muscles of the Rotator Cuff Flashcards

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

Answer: Supraspinatus

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

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

Answer: Supraspinatus tendon

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

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

Answer: Posterior cord

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

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

Answer: External rotation lag sign

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

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

Answer: Long head of the biceps tendon

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

Which rotator cuff muscle has the largest cross-sectional area and is therefore the most powerful?

Answer: Subscapularis

The subscapularis has the largest cross-sectional area of the rotator cuff muscles, making it the most powerful internal rotator.

When performing a 'bear hug test,' the examiner tries to pull the patient's hand off the opposite shoulder while the patient resists. This specifically tests which muscle?

Answer: Subscapularis

The bear hug test places the subscapularis under maximal load by testing its ability to maintain internal rotation against resistance.