Textbook Question
The muscle that rotates the eye medially is the
(a) Superior oblique
(b) Inferior rectus
(c) Medial rectus
(d) Lateral rectus
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10. Muscles
Muscle Naming
2:10 minutesProblem 10
Textbook Question
The major extensor of the elbow is the
(a) Triceps brachii
(b) Biceps brachii
(c) Deltoid
(d) Subscapularis
Verified step by step guidance1
Understand the function of an extensor muscle: Extensor muscles are responsible for increasing the angle of a joint, such as straightening the elbow.
Identify the anatomical location and function of each muscle option: (a) Triceps brachii is located on the posterior side of the upper arm and is responsible for extending the elbow. (b) Biceps brachii is located on the anterior side of the upper arm and primarily flexes the elbow. (c) Deltoid is located on the shoulder and is responsible for arm abduction. (d) Subscapularis is located on the anterior surface of the scapula and is involved in internal rotation of the shoulder.
Focus on the muscle responsible for elbow extension: Based on the anatomical function, the triceps brachii is the major extensor of the elbow.
Eliminate incorrect options: The biceps brachii flexes the elbow, the deltoid abducts the arm, and the subscapularis rotates the shoulder internally. None of these are involved in elbow extension.
Conclude that the correct answer is the muscle responsible for elbow extension, which is the triceps brachii.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Muscle Anatomy
Muscle anatomy refers to the structure and function of muscles in the body. Understanding the major muscle groups, their locations, and their roles in movement is essential for identifying which muscles are responsible for specific actions, such as extending the elbow.
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Elbow Joint Function
The elbow joint is a hinge joint that allows for flexion and extension of the forearm relative to the upper arm. Knowledge of how the elbow functions, including the primary muscles involved in these movements, is crucial for determining which muscle acts as the major extensor.
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Muscle Actions
Muscle actions describe the specific movements produced by muscles when they contract. In the context of the elbow, understanding which muscles are responsible for extension versus flexion helps in identifying the correct answer to questions about muscle function, such as recognizing that the triceps brachii is the primary extensor.
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