Which joint type provides rotary movement around a single axis?

Which joint type provides rotary movement around a single axis?

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

Answer: (D)

The important idea here is how many axes of movement a joint uses and what kind of movement it performs. A pivot joint allows rotation around a single axis, so it enables turning around one central line—think of the forearm rotating the radius around the ulna or the neck turning the head left and right. This makes it uniaxial and purely rotational around one axis. Other joints don’t fit as neatly: ball-and-socket joints move in multiple directions and axes, not just one; gliding joints allow only small sliding movements; hinge joints mainly bend and straighten in one plane (angular movement around a single axis), but not the rotational spinning around a long axis like a true pivot joint. So the joint that provides rotary movement around a single axis is the pivot joint.

The important idea here is how many axes of movement a joint uses and what kind of movement it performs. A pivot joint allows rotation around a single axis, so it enables turning around one central line—think of the forearm rotating the radius around the ulna or the neck turning the head left and right. This makes it uniaxial and purely rotational around one axis.

Other joints don’t fit as neatly: ball-and-socket joints move in multiple directions and axes, not just one; gliding joints allow only small sliding movements; hinge joints mainly bend and straighten in one plane (angular movement around a single axis), but not the rotational spinning around a long axis like a true pivot joint. So the joint that provides rotary movement around a single axis is the pivot joint.