3 Joints in the elbow Flashcards
What type of joint is the elbow joint?
Synovial hinge
How many articulations are in the elbow joint?
- Trochlea notch of ulna and trochlea of humerus
- Head of radius and capitulum of humerus
What other joint has the same bursae as the elbow joint?
Proximal radioulnar joint
What are synovial joints surrounded by?
Fibrous capsule enclosing the joint
What is the benefit of the fibrous capsule around synovial joints?
Strengthens the joint
What is a bursa?
Membranous sac filled with synovial fluid
What is the function of a bursa?
It cushions moving parts of a joint preventing degenerative damage
What clinically important bursae are in the elbow joint?
Intratendinous - within tendon of triceps brachii
Subtendinous - between olecranona and tendon of biceps brachii
Subcutaneous - betweeen olecranoon and overlying connective tissue
Does pronation and supination occur at the elbow joint?
No, occur at nearby radioulnar joint
Where is the medial (ulnar) collateral ligament?
From medial epicondyle to coronoid process of ulna and olecranon of ulna
Where is the lateral (radial) collateral ligament?
From lateral epicondyle to annular ligament of the radius
What is the function of the collateral ligaments?
Stabilise the flexion and extension movements of the elbow
What is the arterial supply to the elbow joint?
Cubital anastamosis formed from branches of brachial and deep brachial artery
What is the nervous supply to the elbow joint?
Anterior: median, radial musculocutaneous nerve
Posterior: ulnar
What movement occurs at the elbow joint?
Flexion and extension
Which muscles cause flexion at the elbow joint?
Brachioradialis and muscles of the anterior compartment of the arm (biceps brachii, brachialis, coracobrachialis)
Which muscles cause extension at the elbow joint?
Muscles of the posterior compartment of the arm (triceps brachii, anconeus)
What are the two radioulnar joints?
Where the radius meets the ulna in the forearm. Proximal and distal
Where are the two radioulnar joints?
Proximal: immediatley distal to elbow joint
Distal: immediatley proximal to wrist joint
What are the articulating surfaces in the proximal radioulnar joint?
Radial head and radial notch of the ulna
What type of joint is the proximal radioulnar joint?
Synovial pivot
What holds the radial head in place in the proximal radioulnar joint?
The radial annular ligament as a collar around the joint
What movement occurs at the proximal radioulnar joint?
Supination and pronation
What are the articulating surfaces in the distal radioulnar joint?
Ulnar notch of the radius and ulnar head
What type of joint is the distal radioulnar joint?
Synovial pivot
What ligaments strengthen the distal radioulnar joint?
Anterior ligament
Posterior ligament
Fibrocartilaginous ligament - articular disk
What are the main muscles producing pronation?
Pronator quadratus
Pronator teres (most powerful)
What accessory muscles produce pronation?
Flexor carpi radialis
Palmaris longus
Brachioradialis
What are the main muscles producing supination?
Supinator
Biceps brachii (most powerful)
What accessory muscles produce supination?
Extensor pollicus longis
Extensor carpi radialis longus
What type of tissue is the interosseous membrane?
A holy sheet of conective tissue
Where is the interosseous membrane?
Medial border of the radius
Lateral border of the ulna
Between two radioulnar joints
What is the function of the holes in the interosseous membrane?
For vascular supply to the forearm
What is the function of the interosseous membrane?
Holds radius and ulna together - additional stability in pronation/supination
Acts as an attachment site for muscles in anterior and posterior compartment of forearm
Transfer forces from the radius to the ulna
