Question

Which of the following is an example of hinge joint?

• A. ( \text{Between the carpals} ) \
• B. ( \text{Between carpal and metacarpal of thumb} ) \
• C. ( \text{Knee joint} ) \
• D. ( \text{Between atlas and axis} ) \

Hint:

To easily identify hinge joints, think of structures that primarily allow bending and straightening in a single plane. Common examples include the elbow, knee, ankle, and the interphalangeal joints of the fingers and toes.

Answer 1

The Correct Option is C

Hinge joints are a type of synovial joint that allow movement primarily in one plane, similar to the hinge of a door. This type of joint enables flexion and extension movements. Let's analyze the given options:

• (A) Between the carpals: The joints between the carpal bones (wrist bones) are primarily plane (gliding) joints, allowing for limited gliding movements.
• (B) Between carpal and metacarpal of thumb: This is a saddle joint, which allows for a wide range of movements including flexion, extension, abduction, adduction, circumduction, and some opposition, making the thumb highly mobile.
• (C) Knee joint: The knee joint is a classic example of a hinge joint, allowing for flexion and extension of the leg. Although it also has a slight rotational component when flexed, its primary movement is hinge-like.
• (D) Between atlas and axis: The joint between the atlas (C1 vertebra) and axis (C2 vertebra) is a pivot joint, which allows for rotational movement of the head (e.g., shaking your head "no").

Therefore, the knee joint is an example of a hinge joint.