MSK 18 - Common Anatomy of the Elbow Flashcards
What are the two articulations of the elbow joint?
What type of joint is the elbow joint?
What are its movements?
1) Humeroulnar joint (distal humerus + proximal ulnar)
2) Humeroradial joint (distal humerus + proximal radius)
- Hinge type synovial (hyaline cartilage)
- Flexion + extension
Describe the osteology + bony prominences of the humerus.
1) 2 x condyles - trochlea + capitulum.
2) 2 x epicondyles - lateral (attachment of extensors in posterior forearm) + medial.
(attachment of flexor-pronator groups in anterior forearm)
3) Radial fossa + Coronoid fossa on front
4) Olecranon fossa on back
Describe the osteology + bony prominences of the ulnar
1) Radial notch + trochlea notch
2) Olecranon
3) Coronoid process
Describe the osteology + bony prominences of the radius
1) Concave head - for articulation with capitulum
2) Neck (just beneath)
3) Radial tuberosity - insertion site for biceps brachii tendon
What are the 3 ligaments of the elbow joint that strengthen the joint capsule?
What is the role of these 3 ligaments?
1) Radial (lateral) collateral ligament - keeps head of radius and capitulum close in pronation + supination.
2) Ulna (medial) collateral ligament
3) Annular ligament - stabilises the proximal radioulnar joint
- Blend with the joint capsule for strength + stability.
When is the elbow joint most stable?
What 3 features contribute to its stability?
- When fully flexed or fully extended.
- Ligaments, bony articulations + muscles.
What are the 2 main bursae within the elbow joint + their role?
1) Subtendinous bursa - reduces friction between triceps tendon + olecranon
2) Olecranon bursa - in subcutaneous tissue overlying olecranon
- Reduce friction between bone + skin/subcutaneous tissue (olecranon), or tendon and bone (subtendinous).
What are the 3 main muscle involved in elbow flexion?
- Think B.B.B
1) Biceps Brachii
2) Brachialis
3) Brachioradialis
Where is the brachialis found? (include compartment)
Where is the brachioradialis found?
- Anterior compartment of arm (BBC), beneath biceps brachii.
- Posterior compartment of forearm (lateral side)
What muscle is involved in elbow extension?
What are the 3 heads of this muscle/what are their origins and insertions
- Triceps brachii (posterior compartment)
1) Long head (infraglenoid tubercle)
2) Medial head (humeral shaft)
3) Lateral head (humeral shaft)
- All 3 insert into the olecranon on elbow
What joint does supination + pronation occur at?
Which muscles perform it in absence/presence of resistance?
Which bone moves/stays still?
- The distal radio-ulnar joints
- Supinator in absence, biceps brachii with resistance (for supination), pronator quadratus + pronator teres (for pronation)
- Radius moves, ulnar stays still.
What actions do the muscles in the anterior forearm perform?
What are the 3 layers of the anterior forearm and how many muscles are in each?
- Flexors + Pronators
- Use “4-1=3”
- Superficial layer = 4
- Middle layer = 1
- Deep layer = 3
What are the 4 muscles of the superficial layer of the anterior forearm?
Where do they all originate from?
What actions do they perform?
- Use PFPF. All originate from medial epicondyle
1) Pronator Teres - pronates forearm
2) Flexor carpi radialis - flexes + abducts wrist
3) Palmaris longus - not everyone has it
4) Flexor carpi ulnaris - flexes + adducts wrist.
What is the 1 muscle of the middle layer of the anterior forearm?
Where does it originate from, what is its action?
- Flexor digitorum superficialis
- Medial epicondyle
- Flexes the metacarpophalangeal joints and proximal interphalangeal joints of the 4 fingers.
What are the 3 muscles of the deep layer of the anterior forearm?
What are their actions?
- Use FFP
1) Flexor digitorum profundus - only one that can flex distal interphalangeal joints of fingers
2) Flexor pollicis longus - flexes interphalangeal joint and metacarpophalangeal joint of thumb.
3) Pronator quadratus - pronates forearm
