Which joint allows rotary movement?

Which joint allows rotary movement?

• A. Plane joint
• B. Hinge joint
• C. Pivot joint
• D. Saddle joint

Answer: (C)

Rotary movement means turning around a single fixed axis. The joint that does this best is the pivot joint. In a pivot joint, one bone rotates around a peg-like projection that fits into a ring formed by another bone and its ligaments. This arrangement lets you rotate movements, such as turning the head side to side or rotating the forearm (the radius turning over the ulna). Other joints don’t primarily enable rotation around a single axis. A plane joint mainly slides or glides with little rotation. A hinge joint allows bending and straightening in one plane. A saddle joint enables movement in two planes but not a true rotation around a single axis.

Rotary movement means turning around a single fixed axis. The joint that does this best is the pivot joint. In a pivot joint, one bone rotates around a peg-like projection that fits into a ring formed by another bone and its ligaments. This arrangement lets you rotate movements, such as turning the head side to side or rotating the forearm (the radius turning over the ulna).

Other joints don’t primarily enable rotation around a single axis. A plane joint mainly slides or glides with little rotation. A hinge joint allows bending and straightening in one plane. A saddle joint enables movement in two planes but not a true rotation around a single axis.