Superior & Inferior Radioulnar JointsSuperior & Inferior Radioulnar Joints

Superior Radioulnar jointSuperior Radioulnar joint• Formed by ulnar radial notch,annular ligament, Formed by ulnar radial notch,annular ligament,

capitulum, and head of radiuscapitulum, and head of radius• Annular ligament encircles the rim of headAnnular ligament encircles the rim of head

Inferior Radioulnar jointInferior Radioulnar joint• Formed by ulnar notch of radius,articular Formed by ulnar notch of radius,articular

disk and head of ulnadisk and head of ulna• Articular disk is referred to as triangular Articular disk is referred to as triangular

fibrocartilage (TFC)fibrocartilage (TFC)

Ligaments:Ligaments:

1.1. Annular ligamentAnnular ligament

2.2. Quadrate ligamentQuadrate ligament

3.3. Oblique cordOblique cord

4.4. Dorsal and palmar radioulnar ligamentDorsal and palmar radioulnar ligament

5.5. Interosseous membraneInterosseous membrane

  

  

Radioulnar articulation:Radioulnar articulation:• Proximal and Distal radioulnar joints are Proximal and Distal radioulnar joints are

mechanically linkedmechanically linked• Motion at one joint is always linked by Motion at one joint is always linked by

motion at another jointmotion at another joint• The distal radioulnar joint is functionally The distal radioulnar joint is functionally

linked to the wrist, hence compressive loads linked to the wrist, hence compressive loads are transmitted from the hand through the are transmitted from the hand through the joint to the radius and ulnajoint to the radius and ulna

  

Axis Of Motion:Axis Of Motion:• The axis of radioulnar joint is a long axis The axis of radioulnar joint is a long axis

extending from the center of the radial head extending from the center of the radial head to the center of the ulnar headto the center of the ulnar head

• In supination both bones lie parallel to each In supination both bones lie parallel to each other where as in pronation radius crosses other where as in pronation radius crosses over ulnaover ulna

During During pronationpronation, the following five motions take, the following five motions takeplace:place:a.a. Radius crosses over the ulna at the superior Radius crosses over the ulna at the superior

radioulnar jointradioulnar jointb.b. Head of the radius spins within the Head of the radius spins within the

osteoligamentous exposure formed by the radial osteoligamentous exposure formed by the radial notch and annular ligamentnotch and annular ligament

c.c. Radial head spins on the capitulumRadial head spins on the capitulumd.d. Concave ulnar notch slides around the ulnar Concave ulnar notch slides around the ulnar

head at the inferior radioulnar jointhead at the inferior radioulnar jointe.e. The articular disk twists at the apex and sweeps The articular disk twists at the apex and sweeps

below the ulnar head below the ulnar head 

• There is minimal contact between the There is minimal contact between the articulating surfaces when the forearm is in articulating surfaces when the forearm is in Supination/pronationSupination/pronation

• Optimal contact occurs when the forearm is Optimal contact occurs when the forearm is in midpronein midprone

• There is negligible motion at the proximal There is negligible motion at the proximal ulna during pronationulna during pronation

• The distal ulnar head moves distally and The distal ulnar head moves distally and dorsally in Pronation and proximally and dorsally in Pronation and proximally and medially in Supinationmedially in Supination

RANGE OF MOTION:RANGE OF MOTION:  • Total range of motion is 150Total range of motion is 150 & is always assessed with  & is always assessed with

elbow in 90elbow in 90 flexion flexion• This position helps to check the rotations at the This position helps to check the rotations at the

radioulnar joint and avoids rotations at the radioulnar joint and avoids rotations at the glenohumeral joint glenohumeral joint 

Factors checking forearm pronationFactors checking forearm pronation1.1. Bone approximationBone approximation2.2. Dorsal radioulnar ligamentDorsal radioulnar ligament3.3. Posterior fibers of MCL of the elbow Posterior fibers of MCL of the elbow  Factors checking forearm supinationFactors checking forearm supination1.1. Palmar radioulanr ligamentPalmar radioulanr ligament2.2. Quadrate ligament Quadrate ligament 3.3. Interosseous membrane Interosseous membrane 4.4. Oblique cordOblique cord

Stability:Stability:

Proximal Radioulnar joint:Proximal Radioulnar joint:

Ligaments:Ligaments:• Annular & quadrate ligamentAnnular & quadrate ligament• Oblique cordOblique cord• Interosseous membraneInterosseous membrane

Muscles:Muscles:• Passive tension in bicepsPassive tension in biceps• Pronator teresPronator teres

Distal Radioulnar joint:Distal Radioulnar joint:Ligaments:Ligaments:• Interosseous membraneInterosseous membrane• Dorsal radioulnar ligamentDorsal radioulnar ligament• Palmar radioulnar ligamentPalmar radioulnar ligament• Triangular fibrocartilageTriangular fibrocartilage• Joint capsuleJoint capsuleMuscles:Muscles:• Pronator quadratusPronator quadratus• Pronator teresPronator teres• Extensor carpi ulnarisExtensor carpi ulnaris• AnconeusAnconeus

Muscles:Muscles: Pronator teres,Pronator quadratus, Biceps Brachii & Pronator teres,Pronator quadratus, Biceps Brachii & SupinatorSupinatorFUNCTIONAL ACTIVITIES (ADL)FUNCTIONAL ACTIVITIES (ADL) : :• Most activities of daily living require a Most activities of daily living require a

combination of motion at the elbow and radioulnar combination of motion at the elbow and radioulnar jointsjoints

• A total of 100A total of 100 of elbow flexion with 100 of elbow flexion with 100 of of supination/pronation is comfortable for simple supination/pronation is comfortable for simple taskstasks

• A range of 30-130A range of 30-130 of elbow flexion with 50 of elbow flexion with 50 of of pronation & 55pronation & 55 of supination to allow the normal of supination to allow the normal functioning of the handfunctioning of the hand

Compression Injury:Compression Injury:

Distraction Injury:Distraction Injury:

Valgus/Varus Injury:Valgus/Varus Injury:

Cubital Tunnel syndrome: