Uniaxial joint; allows flexion/extension movements.
Examples: Knee; elbow; ankle; interphalangeal joints of fingers and toes.
In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (Picture 1 b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanx bones of the fingers and toes.