Shoulder Muscles Quiz

1. Which muscle is chiefly associated with initiating the first part of arm abduction before the deltoid becomes the main mover?

2. Which two muscles form the muscular boundaries of the posterior axillary fold?

3. After injury to the long thoracic nerve, the medial border of a person's scapula becomes prominent when they push against a wall. Which muscle is most directly weakened?

4. A lesion within the quadrangular space could weaken both the deltoid and teres minor. Which nerve passes through this space and supplies those muscles?

5. Which muscle is innervated by the thoracodorsal nerve?

6. A person is asked to rotate the humerus laterally against resistance while keeping the elbow near the torso. Which rotator cuff muscle is a principal contributor?

7. Where does pectoralis minor insert?

8. An axillary nerve injury causes marked weakness when a person tries to continue abducting the arm after the movement has been initiated. Which muscle is most affected?

9. Which rotator cuff muscle primarily medially rotates the humerus?

10. Which list contains all four rotator cuff muscles?

11. Which rotator cuff muscle inserts on the lesser tubercle of the humerus?

12. Which muscle inserts on the middle facet of the greater tubercle of the humerus?

13. Reaching overhead requires upward rotation of the scapula. Which muscles form the key force couple for this movement?

14. During an examination, a clinician tests resisted lateral rotation of the humerus. Which muscle pair is being assessed most directly?

15. A person pulls the shoulder blades toward the vertebral column while maintaining an upright posture. Which muscles are especially responsible for this scapular retraction?

16. Following injury to the spinal accessory nerve, one shoulder droops and shrugging is weak. Dysfunction of which muscle best explains these findings?