Hinge joints allow motion in how many anatomical planes?

Hinge joints allow motion in how many anatomical planes?

• A. One plane
• B. Two planes
• C. Three planes
• D. Infinite planes

Answer: (A)

Hinge joints are uniaxial, meaning they move in one plane. They primarily allow flexion and extension in the sagittal plane around a single axis, like a door hinge that opens and closes. The joint surfaces and ligaments strongly constrain side-to-side movement and rotation, so the main motion remains in that single plane. A tiny amount of rotation can occur when the joint is flexed, but it isn’t considered a primary plane of motion, so the functional movement is effectively in one plane.

Hinge joints are uniaxial, meaning they move in one plane. They primarily allow flexion and extension in the sagittal plane around a single axis, like a door hinge that opens and closes. The joint surfaces and ligaments strongly constrain side-to-side movement and rotation, so the main motion remains in that single plane. A tiny amount of rotation can occur when the joint is flexed, but it isn’t considered a primary plane of motion, so the functional movement is effectively in one plane.