The<unk>  of the<unk>  has a cylindrical form, and on its upper surface is a shallow cup or fovea for articulation with the capitulum (or capitellum) of the humerus.
The circumference of the<unk>  is smooth; it is broad medially where it articulates with the radial notch of the ulna, narrow in the rest of its extent, which is embraced by the annular ligament.
The deepest point in the fovea is not axi-symmetric with the long axis of the<unk> , creating a cam effect during pronation and supination.
Head of radius
Alar plate
Hinge joint
Metatarsus
Greater burdock
Fibrous joint
Axilla
Pawpaw