Anatomy Exam Muscles of the Rotator Cuff 3 — Questions and Answers
Question 1: The rotator cuff contributes to shoulder stability primarily by which mechanism?
- Compressing the humeral head into the glenoid (Correct answer)
- Elevating the acromion
- Tensioning the coracohumeral ligament
- Widening the subacromial space
Correct answer: Compressing the humeral head into the glenoid
The rotator cuff muscles compress the humeral head into the glenoid fossa, providing dynamic stability to the glenohumeral joint.
Question 2: Which two rotator cuff muscles share innervation from the suprascapular nerve?
- Supraspinatus and infraspinatus (Correct answer)
- Supraspinatus and subscapularis
- Infraspinatus and teres minor
- Teres minor and subscapularis
Correct answer: Supraspinatus and infraspinatus
Both the supraspinatus and infraspinatus are innervated by the suprascapular nerve (C5, C6).
Question 3: Teres minor originates from which structure?
- Upper two-thirds of the lateral border of the scapula (Correct answer)
- Infraspinous fossa
- Supraspinous fossa
- Subscapular fossa
Correct answer: Upper two-thirds of the lateral border of the scapula
The teres minor originates from the upper two-thirds of the lateral (axillary) border of the scapula.
Question 4: A full-thickness tear of the supraspinatus tendon would most likely result in weakness of which movement?
- Arm abduction (Correct answer)
- Arm adduction
- Internal rotation
- Horizontal adduction
Correct answer: Arm abduction
The supraspinatus is critical for initiating and maintaining arm abduction, so a full-thickness tear weakens this movement.
Question 5: The subscapularis muscle passes anterior to the shoulder joint and inserts on which structure?
- Lesser tubercle of the humerus (Correct answer)
- Greater tubercle of the humerus
- Surgical neck of the humerus
- Bicipital groove
Correct answer: Lesser tubercle of the humerus
The subscapularis inserts onto the lesser tubercle of the humerus, which is on the anterior aspect of the proximal humerus.
Question 6: Which rotator cuff muscle works synergistically with the infraspinatus to externally rotate the arm?
- Teres minor (Correct answer)
- Subscapularis
- Supraspinatus
- Teres major
Correct answer: Teres minor
The teres minor assists the infraspinatus in externally rotating the arm at the glenohumeral joint.
Question 7: The supraspinatus muscle passes through which anatomical space before inserting on the humerus?
- Subacromial space (Correct answer)
- Quadrangular space
- Triangular space
- Axillary space
Correct answer: Subacromial space
The supraspinatus tendon passes through the subacromial space between the acromion above and the humeral head below.
Anatomy Exam Muscles of the Rotator Cuff 3
The rotator cuff contributes to shoulder stability primarily by which mechanism?