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Proximal & Distal radioulnar joint - Coggle Diagram
Proximal & Distal
radioulnar joint
2 joints are mechanically linked
Classified as pivot joints
Distal radioulnar joint is functionally linked to the wrist
Proximal RU
articulating surfaces
Radial notch on Ulna
Concave in shape and
covered with articular cartilage
Head of the radius
Proximal
the rim of radial head is covered with hyaline cartilage
Humeral capitulum
Already discussed in the elbow joint
This articulation is located near the elbow
radial notch of ulna
annular lig
rim & fovea of the of the head of radius
the humeral capitulum
Annular ligament
nearly circular
att to ant & post edges of radial notch
inner aspect of is lined with articular cartilage that is continuous with the cartilage lining of the radial notch,
creating a fibro-osseous ring within which the head of radius rotates.
Ligaments
3 ligaments
Annular
Ring that encircles the head of radius
Inner surface covered with articular cartilage
Quadrate
Extends from the inferior edge of the radial notch
Inserts onto the neck of radius
Reinforce the inferior aspect of the joint capsule
Maintain radial head in apposition
to the radial notch
Limits the spin of radial head in
supination and pronation
Oblique cord
On ventral forearm
Extends from inferior surface of radial notch
Inserts just below the tuberosity of radius
Fibers are at a right angle to the fibers of interosseous membrane
Assist in preventing separation of radius and ulna
distal RU
articulating surfaces
Ulna notch of the radius
Distal end along the interosseous border
Articulating disc
Triangular shaped
Base attached to the distal edge of ulna
notch of the radius
Apex is attached to fovea of ulna head and
base of the styloid process of Ulna
2 articulating surfaces (concave)
Proximal surface – ulnar head
Distal surface – carpal bones (RCJ)
Head of the Ulna
Convex and covered in articular cartilage
Distal
This articulation is located near the wrist
Ligaments
2 ligaments
Dorsal radioulnar ligament
Dorsal aspect of the ulnar notch
Palmar radioulnar ligament
Palmar aspect of the ulnar notch
2mm longer than dorsal ligament
Longitudinally oriented collagen fibers form the ligaments
Extends along the margin of the articular disc
Inserts onto the fovea and base of
styloid process of Ulna
Interosseous membrane
Provides stabilization for both joints
Located between radius and ulna
3 components
Central band
Thick, strong and ligamentous structure
Fibers run oblique from radius to ulna
High collagen content
Membranous portion
Soft, thin structure
Adjacent to the central tendon
proximally and distally
Dorsal oblique cord
On dorsal forearm
Considered part of the
interosseous membrane
Fibers run counter to the
interosseous membrane