Multiple Choice
The majority of the lever systems in the arms and legs are third-class levers; there are few second-class levers. Knowing this which of the following statements is correct?
10. Muscles
Levers
Struggling with Anatomy & Physiology?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
The elbow is considered a third class lever because:
A
the fulcrum is located between the effort and the load
B
the fulcrum and load are at the same point
C
the effort is applied between the fulcrum and the load
D
the load is positioned between the fulcrum and the effort
Verified step by step guidance1
Understand the concept of levers in the human body: A lever is a rigid structure (like a bone) that moves around a fixed point called the fulcrum. The effort is the force applied to move the lever, and the load is the resistance or weight being moved.
Review the classification of levers: Levers are classified into three types based on the relative positions of the fulcrum, effort, and load. In a third-class lever, the effort is applied between the fulcrum and the load.
Apply the concept to the elbow joint: In the case of the elbow, the fulcrum is the joint itself, the effort is applied by the biceps muscle, and the load is the weight of the forearm or any object being held.
Visualize the mechanics: When the biceps contract, they pull on the forearm (effort), causing it to pivot around the elbow joint (fulcrum) and lift the load (e.g., the forearm or an object). This matches the definition of a third-class lever.
Conclude why the elbow is a third-class lever: The effort is applied between the fulcrum (elbow joint) and the load (forearm or object being lifted), which is the defining characteristic of a third-class lever.
Related Videos
Related Practice
