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 Naming

Anatomy & Physiology

10. Muscles

Muscle Naming

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2:27 minutes

Problem 16

Textbook Question

a. Name two forearm muscles that are powerful extensors and abductors of the hand.
b. Name the sole forearm muscle that can flex the distal interphalangeal joints.

Verified step by step guidance

Step 1: To address part (a), recall that extensors of the hand are located in the posterior compartment of the forearm. Abductors of the hand are muscles that move the hand away from the midline. Identify two muscles that perform both extension and abduction of the hand.

Step 2: For part (a), focus on muscles that act on the wrist joint and are involved in extension and abduction. These muscles typically originate from the lateral epicondyle of the humerus and insert on the metacarpals.

Step 3: To address part (b), recall that flexion of the distal interphalangeal joints is performed by a muscle that acts on the fingers. This muscle must have tendons that insert on the distal phalanges.

Step 4: For part (b), identify the sole forearm muscle responsible for flexing the distal interphalangeal joints. Consider the deep flexor muscles of the forearm and their specific actions.

Step 5: Summarize the anatomical locations and functions of the muscles identified in parts (a) and (b) to ensure clarity and understanding of their roles in forearm movement.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Forearm Muscles

The forearm contains several muscles that are responsible for the movement of the wrist and fingers. These muscles can be categorized into flexors and extensors, with extensors primarily located on the posterior side of the forearm. Understanding the specific muscles involved in extension and abduction of the hand is crucial for identifying the powerful muscles that perform these actions.

Extensors and Abductors

Extensors are muscles that increase the angle between body parts, such as straightening the wrist or fingers. Abductors, on the other hand, are responsible for moving a limb away from the midline of the body. In the context of the forearm, certain muscles serve dual roles as both powerful extensors and abductors of the hand, facilitating a range of movements necessary for various activities.

Distal Interphalangeal Joints

The distal interphalangeal (DIP) joints are the joints located between the last two phalanges of the fingers. Flexing these joints allows for gripping and fine motor movements. The sole forearm muscle capable of flexing the DIP joints is significant in hand function, as it enables the bending of the fingertips, which is essential for tasks requiring precision.