The SUEperior Radioulnar joint Flashcards
Superior Radioulnar Joint Classification
A synovial, pivot joint
The superior radioulnar joint is an articulation between…
The head of the radius rotating within the fibro-osseous ring formed by the radial notch of the ulna and the annular ligament.
Describe the radial notch as an articular surface
Covered in hyaline cartilage
Continuous with the trochlear notch of the ulna on its lateral side, being separated from it by a blunt ridge
Forms 1/5th of the articular fibro-osseous ring but is almost flat vertically.
Name the articular surfaces of the superior radioulnar joint
Head of radius & radial notch
Describe the head of the radius as an articular surface
head of the radius is covered by hyaline cartilage, so forming a smooth surface for articulation with the ulna and annular ligament
Name the ligaments present in the superior radioulnar joint
Annular ligament & quadrate ligament
Describe the structure and location of the annular ligament
Forms the remaining 4/5ths of the articular surface, which encircles the head, and neck of the radius.
Attached to the anterior and posterior margins of the radial notch of the ulna. The diameter between its lower borders is narrower than that above
Annular ligament function
Acts as a restraining ligament preventing downward displacement of the head through the ring.
Quadrate ligament structure and location
Stretches from the lower border of the radial notch of the ulna to the adjacent medial surface of the neck of the radius.
The fibres run in a criss-cross manner, so on movement, some fibres are always under tension.
What movement occurs at the superior radioulnar joint
Pronation (70-90* from normal) and supination (80-90* from normal)
True or false: The superior radioulnar joint had its own joint capsule.
FALSE: it is continuous with the elbow joint and therefore shares the same joint capsule.
