Anatomy Muscles of the Rotator Cuff Questions and Answers

Question 1

A patient presents with significant weakness in initiating arm abduction (the first 0-15 degrees) and pain over the superior aspect of the shoulder.
An MRI confirms a full-thickness tear of a rotator cuff tendon.
Which muscle is most likely affected?

Accepted Answer

Supraspinatus

Answer

Infraspinatus

Answer

Teres Minor

Answer

Subscapularis

Question 2

Which rotator cuff muscle is unique in that it inserts on the lesser tubercle of the humerus, while the other three insert on the greater tubercle?

Accepted Answer

Subscapularis

Answer

Teres Minor

Answer

Infraspinatus

Answer

Supraspinatus

Question 3

A physical examination reveals a patient has marked weakness in external (lateral) rotation of the shoulder. An injury to which pair of rotator cuff muscles would best explain this finding?

Accepted Answer

Infraspinatus and Teres Minor

Answer

Supraspinatus and Subscapularis

Answer

Subscapularis and Teres Minor

Answer

Supraspinatus and Infraspinatus

Question 4

A patient is diagnosed with quadrangular space syndrome, causing compression of the axillary nerve. In addition to the deltoid muscle, which rotator cuff muscle would most likely demonstrate atrophy and weakness?

Accepted Answer

Teres Minor

Answer

Supraspinatus

Answer

Subscapularis

Answer

Infraspinatus

Question 5

Which of the following is the largest and most powerful of the rotator cuff muscles, primarily responsible for medial (internal) rotation of the arm?

Accepted Answer

Subscapularis

Answer

Infraspinatus

Answer

Supraspinatus

Answer

Teres Minor

Question 6

A collegiate baseball pitcher presents with posterior shoulder pain. An MRI reveals inflammation and a partial tear of the muscle that originates in the infraspinous fossa of the scapula and inserts on the middle facet of the greater tubercle. Which muscle has been injured?

Accepted Answer

Infraspinatus

Answer

Supraspinatus

Answer

Teres Minor

Answer

Subscapularis