What type of joint allows for rotational movement and is classified as uniaxial?

• A. Pivot joint
• B. Ball and socket joint
• C. Condyloid joint
• D. Saddle joint

Answer: (A)

The pivot joint is indeed the correct answer as it is specifically designed to allow rotational movement around a single axis, classifying it as a uniaxial joint. In a pivot joint, one bone rotates around another, allowing for a limited range of motion primarily in one plane. This type of movement can be observed in the atlantoaxial joint located between the first two cervical vertebrae, which enables the head to turn from side to side.

In contrast, ball and socket joints allow for a much greater range of motion, including rotational movement as well as flexion, extension, abduction, and adduction, making them multiaxial rather than uniaxial. Condyloid joints allow for movement in two planes but do not facilitate the same type of rotation that is characteristic of pivot joints. Saddle joints, while also allowing for a range of motion, are still classified as biaxial because they facilitate movements in two planes instead of the singular, rotational movement of a pivot joint.