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

Paralysis of which of the following muscles would make an individual unable to flex the thigh?

Iliopsoas

Gluteus maximus

Biceps femoris

Vastus lateralis

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Verified step by step guidance

Step 1: Begin by understanding the action of flexing the thigh. Thigh flexion refers to the movement of the femur (thigh bone) toward the torso, which is primarily performed by muscles located in the anterior compartment of the hip and thigh.

Step 2: Identify the primary muscle responsible for thigh flexion. The iliopsoas muscle, composed of the psoas major and iliacus, is the most important muscle for flexing the thigh at the hip joint.

Step 3: Analyze the role of the other muscles listed in the problem. The gluteus maximus is primarily responsible for extending the thigh, not flexing it. The biceps femoris is part of the hamstring group and is involved in thigh extension and knee flexion. The vastus lateralis is part of the quadriceps group and is responsible for extending the knee, not flexing the thigh.

Step 4: Determine which muscle's paralysis would directly impair thigh flexion. Since the iliopsoas is the primary muscle responsible for this action, its paralysis would make an individual unable to flex the thigh.

Step 5: Conclude that the correct answer is iliopsoas, as it is the muscle essential for thigh flexion, while the other muscles listed perform different actions unrelated to flexing the thigh.