What is Radioulnar the joint?

Radioulnar The joint is one of the two articulations between the radius and the ulna of the bone in the human forearm. When these two bones run parallel, they meet at their upper intersection on the proximal Radioulnar joint and at their lower intersection on the distal Radioulnar joint. Both articulations are a type of synovial joint known as a swivel joint, which means that the joint surfaces of the neighboring bones can rotate around them. Thus, a specific movement of these joints is the rotation of the forearm. As a swivel joint, it includes cylindrical bones - in this case the radius head - with another bone and connected ring of the ligament that rotates around it, the proximal radioular joint is equipped with a ligament connected to the uln known as an annular liga. Like a ring on the finger, he surrounds the head of the radius of the ring ligament and connects to the uln; A part of the ulna, which articulates the head of the radius inside the ring, is a radial notch.

Movement POVOlied in the proximal Radioulnar joint is the supination or rotation of the palm of the forearm. To allow this movement, responsible muscles, biceps brachii at the top of the arm and supinator in the forearm, attach to the radius and pull it during contraction. This causes the radius rotation in the ulna ring ligament. The same rotation occurs in the opposite direction during the movement of the pronation or rotation of the forearm palm, but most of the action occurs on the distal radioulnar joint.

at lower articulation of radius and ulna, distal angry joint, adjacent surfaces are the opposite of those on the proximal joint: the cylindrical head of the ulna meets with ulnar -cut at the bottom of the radius. In this case, both are not held together by not Valán in the shape of a circle, but by Volar and the back of radioulnar ligaments, horizontal ligaments that connect the front and rear aspects of the bones. The structure of this articulation allows pronation and supination, but pronation involves more significant movement on the distal joint.

During the pronation with the muscles of the pronator and the pronator kvaDratus, which are in the forearm and which attach to the side or outer surface of the radius, pull down and pull the bones. This causes the radius to rotate around the ulna so that both bones create X. When the muscles are released, the bones turn around the other on the distal radioulnar joint and return to their neutral, parallel position.