L5 Flashcards
What type of joint is the elbow joint?
Synovial hinge joint
How many planes of movement does the elbow have?
It’s uniaxial - one plane - flexion and extension
What are the articular surfaces of the elbow joint?
- Radius
- Humerus
- Ulna
What are the stabilising factors of the elbow joint?
- The ulnar collateral ligament
- Radial collateral ligament
- Annular ligament.
Where does the musculocutaneous nerve arise from?
The lateral cord
Where does the musculocutaneous nerve pierce?
Coracobrachialis muscle
Where do points where superficial veins pierce deep fascia enter?
Deep veins
What is the medial boundary of the cubital fossa?
Pronator teres
What is the lateral boundary of the cubital fossa?
Brachioradialis
What is the superior boundary of the cubital fossa?
Line between epicondyles
What are the deep contents of cubital fossa?
- Radial nerve (deep & superficial branches)
- Tendon of biceps brachii
- Brachial artery
- Median nerve
What are the superficial contents of cubital fossa?
- Cephalic vein
- Lateral cutaneous nerve of forearm
- Medial cutaneous nerve of forearm
- Basilic vein
- Median cubital vein
What are the three articular surfaces of the elbow?
- Humero-ulnar articulation
- Humero-radial articulation
- Proximal radioulnar joint
Details of humero-ulnar articulation
Trochlea of humerus with trochlea notch of ulna
Details of humero-radial articulation
Capitulum of humerus with head of radius
Details of proximal radioulnar joint
Head of radius articulares with the radial notch of the ulna
What are most hinge joints inforced by?
Strong collateral ligaments
Where does the articular capsule of the elbow project?
Upwards
Why does the articular capsule of the elbow project upwards?
To enclose the radial and coronoid fossae anteriorly and the olecranon fossa posteriorly.
Where does the articular capsule pass inferiorly onto and why?
The neck of the radius to enclose the proximal radioulnar joint
Is the articular capsule of the elbow strong anteriorly and posteriorly?
No needs strong collateral ligament support
What do fat pads function as?
Protective pads
What does pressure on a fat pad cause?
It initiates reflex contraction of antagonist muscles preventing joint damage
What are the intra-capsular features of the elbow?
- Hyaline cartilage and synovium
- Fat pads of the olecranon
- Radial and coronoid fossa
- (some include annular ligament)
Are fat pads extra-synovial?
Yes
What happens to the deeper fibres of strong collateral ligaments?
They blend with capsule
What can the deeper fibres of strong collateral ligaments that blend with capsule be considered?
Intrinsic
What changes during flexion extension of the elbow?
Contact surfaces in the trochlea
Flexion degree of movement in elbow
150º
What is flexion in the elbow enhanced by?
Capitulum and trochlea position
What is flexion in the elbow limited by?
By fit of olecranon into olecranon fossa and fat pad - also sometimes by congenital bone deformity or tightness in anterior structures
What is the most stable position for the elbow joint?
In position of function of hand
How can fracture dislocations be complicated?
By major haemorrhage
Where is the arterial supply to the elbow joint from?
The cubital anastomosis
What does the cubital anastomosis include?
Recurrent and collateral branches from the brachial and deep brachial arteries
What provides the nerve supply for the joint?
By the median, musculocutaneous and radial nerves anteriorly and ulnar nerve posteriorly.
What are the muscles responsible for the extension of the elbow?
- Triceps brachii
- Anconeus
What are the muscles responsible for the flexion of the elbow?
- Brachialis
- Biceps brachii
- Brachioradialis
Does pronation and supination occur at the elbow? If not, where?
No, produced at nearly radioulnar joints.
