Textbook Question
Compare and contrast flexor and crossed-extensor reflexes.
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Ch. 13 The Peripheral Nervous System and Reflex Activity
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
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Hoehn, Haynes, Abbott 12th EditionCh. 13 The Peripheral Nervous System and Reflex ActivityProblem 22
Hoehn, Haynes, Abbott 12th EditionCh. 13 The Peripheral Nervous System and Reflex ActivityProblem 22Chapter 13, Problem 22
Marcus, a football quarterback, suffered torn menisci in his right knee joint when tackled from the side. The same injury crushed his common fibular nerve against the head of the fibula. What locomotor problems did Marcus have after this?
Verified step by step guidance1
Step 1: Understand the anatomy involved. The menisci are cartilage structures in the knee that help cushion and stabilize the joint. Torn menisci can cause pain, swelling, and reduced knee stability, affecting Marcus's ability to move his knee smoothly.
Step 2: Identify the role of the common fibular nerve. This nerve wraps around the neck of the fibula and innervates muscles responsible for dorsiflexion (lifting the foot) and eversion (turning the sole outward) of the foot, as well as providing sensation to parts of the lower leg and foot.
Step 3: Analyze the effects of injury to the common fibular nerve. Damage to this nerve typically results in foot drop, where the individual cannot dorsiflex the foot, leading to difficulty in walking and a characteristic high-stepping gait to avoid dragging the toes.
Step 4: Combine the effects of both injuries. Marcus likely experienced knee instability and pain from the torn menisci, along with motor deficits such as foot drop and sensory loss in the areas supplied by the common fibular nerve.
Step 5: Summarize the locomotor problems. Marcus's locomotor issues would include difficulty bending and stabilizing the knee, inability to lift the foot properly during walking, and altered gait patterns to compensate for these deficits.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Anatomy of the Knee Joint and Menisci
The menisci are C-shaped cartilage structures in the knee that cushion and stabilize the joint. Torn menisci cause pain, swelling, and reduced knee mobility, affecting weight-bearing and movement. Understanding their role helps explain joint dysfunction after injury.
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Introduction to Joints Example 1
Common Fibular Nerve Anatomy and Function
The common fibular nerve wraps around the neck of the fibula and innervates muscles responsible for dorsiflexion and eversion of the foot. Injury to this nerve leads to foot drop and sensory loss on the lateral leg and dorsum of the foot, impairing normal gait.
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Locomotor Impairments from Knee and Nerve Injury
Damage to the menisci and common fibular nerve results in knee instability, pain, and inability to dorsiflex the foot, causing a characteristic foot drop. This leads to an abnormal gait pattern, difficulty walking, and increased risk of falls.
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