Textbook Question
Assume you have a 10-lb weight in your right hand. Explain why it is easier to flex the right elbow when your forearm is supinated than when it is pronated.
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Ch. 10 The Muscular System
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732
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Table of contents
- Ch. 1 The Human Body: An Orientation25
- Ch. 2 Chemistry Comes Alive24
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System12
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton14
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System25
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System25
- Ch. 13 The Peripheral Nervous System and Reflex Activity30
- Ch. 14 The Autonomic Nervous System16
- Ch. 15 The Special Senses26
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart25
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses27
- Ch. 22 The Respiratory System21
- Ch. 23 The Digestive System31
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System26
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System24
- Ch. 28 Pregnancy and Human Development25
- Ch. 29 Heredity11
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
Chapter 10, Problem 21a
Name two muscles in each of the following compartments or regions:
a. thenar eminence (ball of thumb)
b. posterior compartment of forearm
c. anterior compartment of forearm—deep muscle group
d. anterior muscle group in the arm
e. muscles of mastication
Verified step by step guidance1
Identify the muscles located in the thenar eminence, which is the fleshy mound at the base of the thumb. Two key muscles here are the abductor pollicis brevis and the flexor pollicis brevis.
For the posterior compartment of the forearm, focus on muscles primarily responsible for wrist and finger extension. Two examples are the extensor digitorum and the extensor carpi radialis longus.
In the anterior compartment of the forearm, specifically the deep muscle group, look for muscles involved in flexion and pronation of the forearm. Two muscles here are the flexor digitorum profundus and the pronator quadratus.
The anterior muscle group in the arm mainly includes muscles that flex the elbow. Two important muscles are the biceps brachii and the brachialis.
Muscles of mastication are responsible for chewing movements. Two major muscles in this group are the masseter and the temporalis.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Muscle Compartments and Regions
Muscle compartments are groups of muscles enclosed by fascia that share similar functions and innervations. Understanding the anatomical regions like the thenar eminence or forearm compartments helps in identifying which muscles belong to each area based on their location and role.
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Functional Classification of Muscles
Muscles are often classified by their function, such as flexors, extensors, or muscles involved in specific movements like mastication. Recognizing these functional groups aids in recalling which muscles perform particular actions within each compartment or region.
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Anatomy of Specific Muscle Groups
Familiarity with the anatomy of key muscle groups—such as the thenar muscles, forearm deep flexors, posterior extensors, anterior arm muscles, and muscles of mastication—is essential. This includes knowing their names, locations, and primary actions to accurately identify examples from each group.
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Related Practice
Textbook Question
Differentiate between the arrangement of elements (load, fulcrum, and effort) in first-, second-, and third-class levers.
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Textbook Question
Name four criteria used in naming muscles, and provide an example (other than those used in the text) that illustrates each criterion.
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Textbook Question
a. Name the four muscle pairs that act in unison to compress the abdominal contents.
b. How does their arrangement (fiber direction) contribute to the strength of the abdominal wall?
c. Which of these muscles can effect lateral rotation of the spine?
d. Which can act alone to flex the spine?
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Textbook Question
As Kendra's coach watched her sail over the high jump bar, he contracted his right orbicularis oculi muscle, raised his arm, and contracted his opponens pollicis. Was he pleased or displeased with her performance? How do you know?
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Textbook Question
When Mrs. O'Brien returned to her doctor for a follow-up visit after childbirth, she complained that she was incontinent (having problems controlling her urine flow) when she sneezed. The physician asked his nurse to give Mrs. O'Brien instructions on how to perform exercises to strengthen the muscles of the pelvic floor. To which muscles was he referring?
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