Lecture 15 Flashcards
What is the nerve supply of the elbow joint?
Musculocutaneous
Radial
Ulnar
What are the ligaments of the elbow joint?
Ulnar (medial) collateral ligament:
Anterior, posterior, oblique.
Fans out and diverges to coronoid process.
Blends with bone.
Radial (lateral) collateral ligament:
Blends with annular ligament.
What fat pads are found at the elbow joint?
Olecranon
Radial
Coronoid
What movements occur at the elbow joint?
Flexion:
Between humerus and ulnar.
Radial contact at close packed position.
Interosseus membrane is strongest at 90 degrees flexion and mid way between pronation and supination.
Extension:
Limited by oblique angle of trochlear
What is the blood supply of the elbow joint?
Branches of the brachial artery (radial/ulnar)
What is the carrying angle?
Angle created by the arm during elbow extension and forearm supination.
Stops excessive lateral deviation.
Is greater in adults than children.
Is greater in females than males due to the hip.
What are the flexion muscles at the elbow joint?
Biceps brachii
Brachialis
Brachioradialis
What are the extension muscles at the elbow joint?
Triceps brachii
Anconeus
What is the purpose of the interosseus membrane between the radioulnar joints?
Obliquely orientated to transmit forces between the radius to the ulnar.
20% through radius at proximal end.
80% through radius at distal end.
What nerve supplies the proximal radioulnar joint?
Median
Musculocutaneous
Radial
What artery supplies the proximal radioulnar joint?
Branches of the deep radial and ulnar arteries.
What is the purpose of the sacciform recess?
Extension of the joint capsule that allows laxity for supination and pronation to take place.
What two bones is the proximal radioulnar joint in between?
The head of the radius and the radial notch of the ulnar.
What are the ligaments of the proximal radioulnar joint?
Annular ligament - ring that fits around head of radius
Quadrate ligament - extends to neck of radius, provide extra support
Interosseus membrane
What bones is the distal radioulnar joint in between?
Head of ulna and ulnar notch on radius.
What is the nerve supply of the distal radioulnar joint?
Median (anterior)
Radial interosseus (posterior)
What is the triangular ligament?
Fibrocartilaginous articular disc
Takes the force of supination and pronation
What movements occur at the radioulnar joints?
Pronation
Supination
Working along with flexion and extension
Midprone position is the most stable
What muscles do pronation ?
Pronator teres
Pronator quadratus
Assisted by:
FCR
Palmaris longus
Brachioradialis
What muscles do supination ?
Supinator
Biceps brachii
Assisted by:
Extensor pollicis longus
ECRL
Why does the proximal radioulnar joint often dislocate in children?
The annular ligament is lax in children.
How does the proximal radioulnar joint dislocate?
Radial head is displaced.
Muscle pulls radial head superiorly.
How can a dislocated proximal radioulnar joint be fixed?
Supinate forearm
Push proximally
Joint in flexion
Where can avulsion fractures occur?
Medial epicondyle of humerus (ulnar nerve is endangered).
Styloid process of ulnar
Fall on a flexed elbow:
Olecranon process of ulna
Coronoid process of ulna
What are the clinical considerations at the humeroulnar and radioulnar joints?
Bursitis
Epicondylitis
Avulsion fractures
Supracondylar fracture of humerus - Volkmann’s ischemic contracture
