Joint · Elbow

Elbow joint

Articulatio cubiti

The hinge of the arm. Two articulations share one capsule here: the humerus with the ulna, which is the true hinge and does most of the work, and the humerus with the head of the radius. The trochlea of the humerus and the notch of the ulna interlock closely, which makes the elbow one of the most inherently stable joints in the body — its bones, not just its muscles, hold it together. The same capsule also contains the upper radioulnar joint, so bending the elbow and turning the palm happen inside one continuous space.