Which type of joint allows the widest range of motion, including ball-and-socket?

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

Answer: (B)

The type of joint that allows the widest range of motion is the ball-and-socket joint. Its ball-shaped end fits into a cup-like socket, which lets the bone move in multiple directions: flexion and extension, abduction and adduction, rotation, and the combination of these (circumduction). Because it’s multiaxial, it has three degrees of freedom, as seen in the shoulder and hip joints, giving the greatest overall mobility.

Hinge joints restrict movement to a single plane around one axis—like bending and straightening the elbow. Pivot joints allow rotation around a single axis, such as the radioulnar joint. Saddle joints permit movement in two planes but don’t enable the wide rotational range of ball-and-socket joints, as seen in the thumb.