Articulatio radioulnaris proximalis

from Wikipedia, the free encyclopedia

The articulatio radioulnaris proximalis ("body-close spoke- ulnar joint") is the articulated connection between the forearm bones of the radius ( radius ) and ulna ( ulna ) and a partial joint of the elbow joint . Functionally, it is a pivot joint with one degree of freedom in which the spoke rotates around the longitudinal axis in a recess in the ulna and thus - with the involvement of the radioulnar joint remote from the body - enables the hand to turn around ( pronation and supination ).


The articular surface of the spoke is called the circumferentia articularis radii . It is wider on the inside (medial) than on the outside (lateral). The retraction at the ulna is known as the incisura radialis ulnae and is separated from the articular surface for the humerus ( incisura trochlearis ) by a narrow ridge. The joint is stabilized by the annular radial ligament ( ligamentum annulare radii ), which arises on both sides at the incisura radialis ulnae , embraces the head of the spoke and presses it into the elbow. On the inside, this band has a cartilage- like structure and also serves as a joint surface.

Species differences

Movement in the proximal radioulnar articulation is severely restricted in many mammals , who mainly specialize in straight running . In ungulates , the joint is immobile. In pigs , the ulna and radius are fixed by tight ligaments. In ruminants and horses , the head of the ulnar and the head of the spoke are fused to one another so that no spoke-ulnar joint is formed.

In birds , a meniscus ( meniscus radioulnaris ) is embedded in the radial-ulnar joint , the ventral edge of which is fused with the joint capsule, while the thick dorsal edge remains free. The ligament between the ulna and the radius is called the transverse radioulnare ligament .


  • Ibrahim A. Kapandji: Functional Anatomy of the Joints: Schematically and annotated drawings on human biomechanics. 4th edition. Georg Thieme Verlag, 2006, ISBN 3-13-142214-9 , p. 106.
  • Franz-Viktor Salomon: Radioulnar Joints. In: Anatomy for veterinary medicine. 2nd ext. Edition. Enke, Stuttgart 2008, ISBN 978-3-8304-1075-1 , p. 129.
  • Franz-Viktor Salomon: Connections of the bones of the wing. In: Salomon (ed.): Textbook of poultry anatomy . Fischer Jena / Stuttgart 1993, ISBN 3-334-60403-9 , pp. 70-72.