Lecture - The Elbow and Radio-Ulnar Joints Flashcards
Which bones articulate at the elbow joint?
Medially, the trochlear notch of the ulna and the trochlea of humerus
Laterally, the head of the radius with the capitulum of the humerus
What angle does the elbow extend maximally to?
170*
Which muscles perform flexion of the elbow?
Biceps brachii, brachialis an brachioradialis
Which muscles perform extension of the elbow?
Triceps brachii and anconeus
What strengthens the elbow joint?
What aspects may be weak?
Strong fibrous capsule and collateral ligaments (medial and lateral)
Hence, posterior and anterior weak as no ligaments
Which ligament stabilises the lateral aspect of the elbow joint?
Where does it stretch between?
Radial collateral ligament
Originates at the lateral epicondyle and fans outwards to blend with the annular ligament
Which aspect of the elbow joint does the ulnar collateral ligament stabilise? What does it stretch between?
Medial
Extends from medial epicondyle in 3 bands, all of which end up at conoid process or olecranon
Which 3 bursae are clinically important in the elbow?
Intratendinous
Subtendinous
Subcutaneous
Where are the intratendinous, subtendinous and subcutaneous bursae of the elbow located?
Intratendinous = within triceps tendon Subtendinous = between olecranon and triceps tendon Subcutaneous = between olecranon and overlying connective tissue
Why might subtendinous bursitis occur?
Which movement would be most painful, and why?
Excessive flexion and extension of the elbow
Flexion more painful as puts more pressure on bursa
Why might subcutaneous bursitis occur?
Repeated pressure/friction on the subcutaneous bursa, e.g. from leaning on elbow
Which bones articulate at the proximal radioulnar joint?
What about at the distal radioulnar joint?
Proximal - radial head with radial notch of ulna
Distal - ulnar head with ulnar notch of radius
What ligament holds the radial head at the proximal radioulnar joint?
The annular ligament
How is friction reduced between the radius and the annular ligament?
Annular ligament lined with synovial membrane
What movement occurs at the proximal radioulnar ligament?
Radial head rotates within annular ligament, allowing pronation and supination
Which muscles perform pronation and supination of the forearm?
Pronation = pronator teres and pronator quadratus Supination = biceps brachii and supinator
Do any ligaments strengthen the distal radioulnar joint?
Yes - posterior and anterior ligaments, and articular disc
What does the articular disc at the distal radioulnar joint achieve?
Separates joint from wrist
Binds R and U together during movement
What movement occurs at the distal radioulnar joint?
Ulnar notch of radius slides anteriorly over ulnar head - allows pronation and supination.
What is the interosseous membrane of the forearm and where is it located?
Sheet of connective tissue connecting the radius and ulna
Stretches between medial edge of radius and lateral edge of ulna
What are the functions of the interosseous membrane?
- Holds radius and ulna together during pronation
- Acts as an attachment site for some muscles
- Transfers force from radius to ulna
What sort of joint is the elbow joint?
What about the radioulnar joints?
Elbow = hinge type synovial joint
Radioulnar joints = pivot type synovial joints
