It is the lateral bone of the forearm. It is the shorter of the two bones in the forearm. It articulates proximally with the humerus and ulna and distally with the carpal bones and ulna. It has two epiphyses and a diaphysis.

Proximal Epiphysis

  • Head – It is cylindrical and articulates with the humeral capitulum
  • Glenoid cavity – Articulates with the capitulum (humerus)
  • Radius Neck – Rounded, smooth, strangled portion located below the head
  • Radial tuberosity – medially located eminence into which the tendon of the biceps brachii attaches

Distal Epiphysis

  • Ulnar Notch – Articular face to the ulna
  • Carpal Notch – It is concave, smooth and articulates with the scaphoid and lunate bones
  • Styloid Process - Conical Projection


It has three edges and three faces.


  • Interosseous Edge
  • Front Edge
  • Dorsal Edge


  • Front Face
  • Dorsal Face
  • Side Face

The Radius articulates with four bones: the Humerus, Ulna, Scaphoid and Semilunar.

Articulações Proximais do RádioArticulações Distais do Rádio

 Rádio - Vistas Anterior, Posterior e Medial
Source: SOBOTTA, Johannes. Atlas of Human Anatomy. 21 ed. Rio de Janeiro: Guanabara Koogan, 2000.

Are you ready to test your knowledge? Then click below to take the quiz on the subject.
Continue your studies on related systems