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Dr. Vohra

Elbow Radioulnar & Wrist Joints

Bones involved are

Elbow JointType Hinge type of synovial joint

ArticulationB/W the trochlea & capitulum of humerus & trochlear notch of ulna & head of the radius

Fibrous CapsuleThe fibrous capsule completely encloses the joint. Its anterior and posterior parts are thin and weak, but collateral ligaments strengthen its sides. The fibrous capsule is attached to the proximal margins of the coronoid and radial fossae anteriorly, but not quite to the superior limit of the olecranon fossa posteriorly. Distally the fibrous capsule is attached to the margins of the trochlear notch, the anterior border of the coronoid process, and the annular ligament.

Synovial membraneLines the internal surface of the fibrous capsule

LigamentsLateral ligamentMedial ligament

Lateral ligament (radial collateral)Is triangular ligament, its apex is attached proximally to the lateral epicondyle of the humerus and its base blends with the annular ligament of the radius

Medial ligament (ulnar collateral)It is composed of anterior and posterior bands (parts), which are connected by a thinner, relatively weak oblique band. Its apex is attached to the medial epicondyle of the humerus. The strong cord-like anterior part is attached to the tubercle on the coronoid process of the ulna and the weaker fan-like posterior part is attached to the medial edge of the olecranon. The ulnar nerve passes posterior to the medial epicondyle and is closely applied to the ulnar collateral ligament.

Movements & muscles of the Elbow joint

This joint can be flexed or extended Flexion is produced by the brachialis and brachioradialis muscles, but the main flexor is the brachialis. When the forearm is supinated, the biceps brachii muscle also flexes this joint; when it is pronated, the pronator teres does.

The main extensor of the elbow joint is the triceps brachii muscle. Gravity and the anconeus muscle assist with this movement.

Blood supply of the Elbow joint

Relations of the elbow joint Anteriorly: Brachialis, tendon of biceps, median nerve & brachial arteryPosteriorly: Triceps a small bursaMedially: Ulnar nerve Laterally: Common extensor tendon & supinator

Nerve supply The joint is supplied by the branches of median, ulnar, musculocutaneous & radial nerves

Carrying angle of the Elbow joint

Radioulnar JointThe radius and ulna articulate with each other at their proximal and distal ends at synovial joints, called the proximal and distal radioulnar joints. These articulations are the pivot type of synovial joint that produces pronation and supination.

ArticulationThe radial head articulates with the radial notch of the ulna. The head of the radius is held in position by the strong annular (annular) ligament,

Fibrous CapsuleThe fibrous capsule enclosing the joint is continuous with the fibrous capsule of the elbow joint

Synovial membraneThe deep surface of the annular ligament is lined with synovial membrane. Continues above with elbow joint

LigamentsThe annular ligament is attached to anterior & posterior margins of radial notch. It is continuous with the capsule of the elbow joint. It is not attached to radius

Proximal radioulnar joint

Movementspronation and supination of the forearm

RelationsAnteriorly: Supinator & radial nervePosteriorly: Supinator & common extensor tendonMedially: Ulnar nerve Laterally: Common extensor tendon & supinator

Nerve supply The joint is supplied by the branches of median, ulnar, musculocutaneous & radial nerves

Distal radioulnar jointType Pivot type of synovial joint

ArticulationHead of the ulna & ulnar notch of radius

Capsule The capsule encloses the joint but deficient superiorly

LigamentsWeak anterior & posterior ligaments strengthen the joint

Articular discTriangular fibrocartilaginous, separates the cavity of the distal radioulnar joint from the cavity of the wrist joint. Unites the radius & ulna

Synovial membraneLines the capsule

Nerve supply Anterior interosseous & deep branch of radial nerves

MovementSupination & pronation

Distal radioulnar joint

Type It is a condyloid type of synovial joint

Articulationdistal end of the radius and the articular disc above & scaphoid, lunate & triquetral bones below

Capsule The capsule encloses the joint & is attached above to the distal ends of radius & ulna below to the proximal row of carpal bones

LigamentsAnterior & posterior ligaments strengthen the capsule the medial is attached to the styloid process of ulna & to the triquetral bone. The lateral ligament is attached to the styloid process of radius & to the scaphoid bone

Wrist joint (radiocarpal)

Synovial membraneLines the capsule & attached to the margins of the articular surfaces. The joint cavity does not communicate with that of distal radioulnar joint or with the joint cavities of intercarpal joints

Nerve supply Anterior interosseous & deep branch of radial nerves

MovementThe movements of adduction, abduction, flexion, extension and circumduction are possible. Rotation of the wrist joint is impossible because the articular surfaces are ellipsoid in shape; however, pronation and supination of the hand compensate for the absence of this movement

Cont. Wrist joint (radiocarpal)

Fractures of the wrist (e.g., Colles' fracture) involving the distal end of the radius are the most common type of fracture in persons over 50 years of age