Radioulnar Joint Flashcards
What are the radioulnar joints?
Two locations in which the ulna and radius articulate in the forearm
Where is the proximal radioulnar joint?
Immediately distal to the elbow joint
What is the proximal radioulnar joint the articulation of?
The head of the radius, and the radial notch of the ulna
Where is the distal radioulnar joint?
Just proximally to the wrist joint
What is the distal radioulnar joint the articulation of?
Between the radial notch of the radius and ulnar head
What are the radioulnar joint classified?
Pivot joints
What are the radioulnar joints responsible for?
Pronation and supination of the forearm
What is the proximal radioulnar joint enclosed within?
The same articular capsule as the elbow joint
What is the proximal radioulnar joint formed from?
An articulation between the head of the radius and the radial notch of the ulna
How is the radial head held in place?
By the annular radial ligament
What does the annular radial ligament form?
A ‘collar’ around the joint
What is the annular radial ligament lined with?
A synovial membrane
What is the purpose of the synovial membrane of the annular radial ligament?
It reduces friction during movement
How is movement at the proximal radioulnar joint produced?
By the head of the radius rotating within the annular ligament
What movements are possible at the proximal radioulnar joint?
Pronation and supination
What is pronation at the proximal radioulnar joint produced by?
The pronator quadratus and the pronator teres
What is supination at the proximal radioulnar joint produced by?
The supinator and biceps brachii
What is the distal radioulnar joint an articulation between?
The ulnar notch of the radius, and the ulnar head
What strengthens the distal radioulnar joint?
Anterior and posterior ligaments
The articular disc
What is the articular disc?
A fibrocartilaginous ligament
What is the function of the articular disc?
Binds the radius and ulna together, and holds them together during movement at the joint
Separates the distal radioulnar joint from the wrist joint
What does the distal radioulnar joint allow for?
Pronation and supination
What happens to the ulnar notch of the radius in movements of the distal radioulnar joints?
It slides over the head of the ulnar
What produces pronation at the distal radioulnar joints?
The pronator quadratus and pronator teres
What produces supination at the distal radioulnar joint?
Supinator and biceps and brachii
What is the interosseous membrane?
A sheet of connective tissue that joins the radius and ulna together between the radioulnar joints
What does the interosseous membrane span?
The distance between the medial radial border and the lateral ulnar border
What is present in the interosseous membrane?
Small holes
Why are there small holes in the interosseous membrane?
As a conduit for the forearm vasculature
What are the major functions of the interosseous membrane?
Holds radius and ulna together during pronation and supination of the forearm, providing additional stability
Acts as a site of attachment for muscles in the anterior and posterior compartments of the forearm
Transfers forces from the radius to the ulna
How can the radius and ulna be thought of when dealing with injury?
As a ring
What is the result of the radius and ulna being thought of as a ring?
A ring usually breaks in two places, meaning that a fracture to the radius usually causes a fracture or dislocation to the other bone
