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

Contraction of the pectoralis minor muscle results in which of the following actions?

Extends the humerus

Retracts the scapula

Elevates the scapula

Protracts and depresses the scapula

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Verified step by step guidance

Step 1: Begin by identifying the location and function of the pectoralis minor muscle. The pectoralis minor is a thin, triangular muscle located beneath the pectoralis major in the chest region. It originates from the anterior surfaces of the third, fourth, and fifth ribs and inserts onto the coracoid process of the scapula.

Step 2: Understand the role of the pectoralis minor in movement. This muscle is primarily responsible for stabilizing the scapula by pulling it downward and forward against the thoracic wall. This action is referred to as protraction and depression of the scapula.

Step 3: Analyze the options provided in the question. The actions listed include extending the humerus, retracting the scapula, elevating the scapula, and protracting and depressing the scapula. Compare these actions to the known function of the pectoralis minor.

Step 4: Eliminate incorrect options based on anatomical knowledge. Extending the humerus is a function of muscles like the latissimus dorsi and posterior deltoid, not the pectoralis minor. Retracting the scapula is performed by muscles such as the rhomboids and trapezius. Elevating the scapula is the action of the levator scapulae and upper trapezius.

Step 5: Confirm that the correct action of the pectoralis minor is protraction and depression of the scapula. This matches the anatomical function of the muscle, as it pulls the scapula forward and downward.