Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

10. Muscles

Muscle Actions

Anatomy & Physiology

10. Muscles

Muscle Actions

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Multiple Choice

Which of the following muscles is the prime mover for flexion of the arm at the shoulder?

Latissimus dorsi

Deltoid (posterior fibers)

Trapezius

Pectoralis major

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Verified step by step guidance

Step 1: Understand the concept of 'prime mover' in muscle actions. The prime mover, also known as the agonist, is the muscle primarily responsible for producing a specific movement. In this case, the movement is flexion of the arm at the shoulder.

Step 2: Recall the anatomy of the shoulder joint and the muscles involved in arm flexion. Flexion refers to moving the arm forward and upward, decreasing the angle between the arm and the torso.

Step 3: Analyze the function of each muscle listed in the options: - Latissimus dorsi: This muscle is primarily involved in extension, adduction, and medial rotation of the arm, not flexion. - Deltoid (posterior fibers): These fibers are responsible for extension and lateral rotation of the arm, not flexion. - Trapezius: This muscle primarily stabilizes and moves the scapula, not directly involved in arm flexion. - Pectoralis major: This muscle is responsible for flexion, adduction, and medial rotation of the arm at the shoulder joint.

Step 4: Focus on the pectoralis major. This muscle originates from the clavicle, sternum, and ribs, and inserts into the humerus. Its contraction pulls the arm forward and upward, making it the prime mover for flexion of the arm at the shoulder.

Step 5: Conclude that the pectoralis major is the correct answer based on its anatomical function and role as the prime mover for arm flexion at the shoulder joint.