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

What is the primary action of the trapezius muscle?

Extension of the knee

Flexion of the forearm

Adduction of the thigh

Elevation, retraction, and rotation of the scapula

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Verified step by step guidance

Begin by identifying the location and attachment points of the trapezius muscle. The trapezius is a large, superficial muscle that extends from the occipital bone at the base of the skull, down to the lower thoracic vertebrae, and laterally to the scapula.

Understand the anatomy of the trapezius muscle. It is divided into three parts: the upper, middle, and lower fibers, each contributing to different movements of the scapula.

Consider the actions of the upper fibers of the trapezius. These fibers are responsible for elevating the scapula, which is the movement of lifting the shoulder girdle upwards.

Examine the role of the middle fibers of the trapezius. These fibers retract the scapula, pulling it towards the spine, which is important for stabilizing the shoulder during various activities.

Analyze the function of the lower fibers of the trapezius. These fibers assist in rotating the scapula, which is crucial for raising the arm above the head. Together, these actions contribute to the overall movement and stability of the shoulder girdle.