Chapter 17 - The Elbow Flashcards
What are the functions of the elbow?
- enables proper positioning of the hand
- allows transmission of power from the shoulder to the hand
- augmenting the versatility and agility of the UE
Where does the anterior joint capsule originate and insert?
Origin = distal humerus proximal to radial and coronoid fossa Insert = distally into the rim of the coronoid and annular ligament
Where does the posterior joint capsule attach?
Attaches distally along the articular margin of the sigmoid notch and proximal aspect of olecranon process
What type of joint is the humeroulnar joint?
Uniaxial hinge joint (between trochlea of humerus and trochlear notch of ulna)
What is the capsular pattern of the humeroulnar joint?
Flexion, extension
What are the resting and closed packed positions of the humeroulnar joint?
Resting = 70 elbow flexion, 10 supination Closed = extension and supination
What type of joint is the humeroradial joint?
Uniaxial hinge joint (between capitullum and radial head)
What is the capsular pattern of the humeroradial joint?
Flexion, extension
What are the resting and closed packed positions of the humeroradial joint?
Resting = full extension and full supination Closed = elbow flexed to 90, forearm supinated to 5
What causes Nursemaid’s Elbow?
Caused by a sudden pull on extended, pronated arm causing a dislocation of the radial head
What type of joint is the proximal radioulnar joint?
Uniaxial pivot joint (between radial head and radial notch of ulna)
What is the capsular pattern of the proximal radioulnar joint?
Equal limitation of supination and pronation
What are the resting and closed packed positions of the proximal radioulnar joint?
Resting = 35 supination, 70 elbow flexion Closed = 5 supination
What are the 3 components of the medial collateral ligament?
1) anterior bundle
2) transverse bundle
3) posterior bundle
What shape is the MCL? With what other structure does it form a tunnel?
- fan-shaped
- FCU, tunnel for ulnar nerve
What shape is LCL?
Cord-like structure
What is the function of the LCL?
- to maintain the humeroulnar and humeroradial joints when the elbow is loaded in supination
- stabilizes proximal radioulnar joint during full supination and pronation
What is the function of the annular ligament?
Checks displacement of the radial head
List the elbow flexors
Biceps Brachii Brachialis Brachioradialis Pronator Teres ECRL FCR FCU
List the forearm pronators
Pronator teres
Pronator quadratus
FCR
List the forearm supinators
Biceps Brachii
Supinator
List the elbow extensors
Triceps Brachii
Anconeus
What passes through the cubital tunnel?
Ulnar nerve
What forms the borders of the cubital tunnel?
Floor = MCL Roof = aponeurosis, arcuate ligament Posterior = medial head triceps Anterior = medial epicondyle Lateral = olecranon
