Elbow Flashcards
What 2 articulations make up the elbow joint?
- HUMERO-ULNAR (trochlea of humerus and trochlear notch of ulna)
- Humero-radial (capitulum of humerus, and upper surface of radial head)
What reinforces the elbow capsule?
Laterally - radial collateral ligament
Medially - ulnar collateral ligament
(Thin post/ant - allows flexion/extension)
What type of dislocation of the elbow occurs 80-90% of the time?
Posterior.
-humerus goes ant, radius and ulnar project post
What are the 2 main causes of posterior dislocation of the elbow?
FOOSH -elbow flexed
-Hyperextension
What are 3 findings with post elbow dislocation?
- Ulnar collateral ligament torn
- Fractures to radial head, coronoid procees & olecranon process
- Ulnar nerve injury
Where does the ulnar nerve pass in the elbow joint?
Between the olecranon process(ulnar) and medial epicondyle(humerus)
What muscle in the wrist is supplies by the ulnar nerve?
FCU
What is the sensory supply of the ulnar nerve?
Med palm & med 1 1/2 digits
What are symptoms of ulnar nerve damage?
- Numb med palm and 1 1/2 digits
- Weak flexion and adduction of the wrist
What is the difference between a simple and comple elbow dislocation?
Simple - normally ligamentous, not bone fracture
Complex - associated with bone fracture
What normally prevent hyperextension at elbow?
Olecranon contact with olecranon fossa.
NB. some people have olcranon FORAMEN - can hyperextend elbow
What are the 3 flexors of the elbow joint?
- brachialis
- biceps brachii
- brachioradialis (when forearm is mid-pronated)
What is the extensor at the elbow?
Triceps brachii
Why is brachioradialis unusual?
Classified as extensor compartment, but passes ant to elbow
What is the origin of triceps brachii? (3)
Long head - infraglenoid tubercle on the scapula
Lateral head - Posterolateral humerus above spinal groove
Medial head - posteromedial humerus below spinal groove
What is the common insertion of triceps brachii?
Olecranon process (ulna)
Innervation of triceps brachii?
Radial nerve (C5-T1)
What is the olecranon bursa?
Synovial fluid sac around olecranon process
What is bursitis of the elbow and what causes it?
Inflammation of olecranon bursa.
-Excess repeated pressure/friction
What is the annular ligament?
Wraps around head of radius - allows rotation of humerus (pronation/supination)
-NB. weak in childhood - more likely to dislocate
What is ‘nursemaids’/pulled elbow syndrome?
Dislocation of radius laterally due to biceps brachii. Common in children (parents swinging arms).
What is the proximal radioulnar joint and where is it located?
Articulation between radius head and radial notch (ulnar).
-located in elbow capsule
What are the movements of the prox radio-ulnar joint?
Pronation/supination
What happens to the radial tuberosity during pronation?
Moves from med to lat
What 2 muscles contract to move the forearm from the supinated to pronated position, and what nerve innervates them?
- Pronator teres
- Pronator quadratus
Innervated by median nerve
Which 2 muscles contract to move the forearm from the pronated to suppinated position and what nerves innervate them?
- Supinator
- Biceps brachii
Innervated by radial nerve/musculocutaneous
What is the 1* function of biceps?
Supination (arm)
What is golfer’s elbow?
Flexor tendon inflammation at med epicondyle
What is tennis elbow?
Flexor tendon inflammation at lat epicondyle
Treatment; coritcosteroid injection
What is avulsion of the medial epicondyle?
What is a big risk involved?
Medial epicondyle is pulled out of position.
- Med epicondyle ossifies separate to humerus
- Risk; ulnar nerve stretching
What is a common humeral fracture in the elderly? What nerve is often damaged?
Fracture to surgical neck.
-Axillary nerve as it wraps around the surgical neck (test deltoid function and badge area sensation)
What commonly occurs in a humeral shaft fracture and what is the possible nerve damage associated?
Bone fractures along radial groove, then deltoid pulls it laterally.
Radial nerve may be damaged (>wrist extensor paralysed)
What is a supracondylar fracture of the humerus?
Fracture just above condylar; humerus pushed anteriorly.
Common in chiildren.
Which vessels and nerves are at risk of damage in a supracondylar fracture?
Median nerve and brachial artery (anterior to humerus).
-hand goes blue (necrosis risk)
What are the 4 wrist flexor muscles?
- pronator teres
- FCR
- palmaris longus
- FCU
