The Elbow Flashcards
Classify the Elbow Joint
synovial, compound, uniaxial, hinge joint
Describe the articular surfaces of the elbow joint
Between distal end of humerus and proximal ends of ulnar and radius.
Humeroulnar articulation: - pulley shaped trochlea of humerus is convex AP, articulates with deep trochlear notch of ulnar which is concave AP - offering close bony congruency.
Humeroradial articulation: - hemispherical capitulum of anteroinferior humerus articulates with shallow concavity on superior surface of radial head
what is normal carrying elbow of the elbow?
5 to 15 degrees
Describe the joint capsule of the elbow
- forms a complete cuff around the elbow and superior radioulnar joint
- attaches to medial epicondyle anteriorly and proximally
- arches upwards and laterally - beyond the margins of the coronoid and radial fossa
- to the articular margin of the capiitulum
- posteriorly, extends from the capitulum - arches upwards around the olecranon fossa to medial epicondyle
- anteriorly and distally, attaches to margins to trochlear notch around olecranon and coronoid processes of ulna
- does not attach directly to radius - blends with annular ligament to enclose radial head
what reinforces the joint capsule?
strong collateral ligaments
- weak anteriorly and posteriorly -
Describe the synovial membrane of the elbow joint
lines the internal fibrous capsule - attaches to articular margins of humerus and ulna.
Reflects upwards to cover coronoid and radial fossa - anteriorly, and the olecranon fossa - posteriorly.
Distally - SM continues continues into the SRUJ to cover the annular ligamnet and reflect onto neck of radius.
Extensive and forms many synovial folds,
Shape of Ulnar Collateral Ligamnet
Thick anterior and posterior bands with thin intermediate portion
Shape of Radial collateral ligament
Strong triangular band
Blends with annular ligament
Shape of Quadrate ligament
Fibres run in criss-cross manner – to cause constant tension on ligament
Shape of Annular Ligament
Thick ring like band
Attachments of Ulnar collateral ligament
O: Anterior band – front of medial epicondyle
Intermediate band – undersuface of medial epicondyle
Posterior band – back of medial epicondyle
I: Anterior band – medial edge of coronoid process, Intermediate band – joins anterior and posterior bands, posterior band – medial edge of olecranon.
function of ulnar collateral ligamnet
Prevents excessive valgus movement
Attachments of Radial Collateral Ligamnet
O: anteroinferior lateral epicondyle
I: margins of radial notch of the ulna
Function of radial collateral ligamnet
Prevents excessive varus movement
Attachments of annular ligamnet
O: Anterior margins of radial notch of ulna
Encircle the head and neck of radius
I: posterior margins of radial notch of ulna
Function of the annular ligament
Anchors the head of the radius within the joint and facilitates movement.
Attachment of the quadrate ligament
O: lower border of radial notch of ulna
I: adjacent medial surface of neck of radius – proximal to radial tuberosity
Function of the Quadrate ligament
Maintain stability of the superior radioulnar joint during pronation and supernation.
Nerve supply to the elbow joint
twigs from musculocutaneous, medial and radial nerves anteriorly, and ulnar and radial nerves posteriorly – C5-C8
what are the stabilising factors of the elbow joint?
Shape of articulating surfaces – trochlear, capitum, trochlear notch and radial head.
Strong collateral ligaments
Muscular cuff of triceps, biceps, mbrachialis and brachioradialis
Common tendons of superficial flexors and extensors from the medial and lateral epicondyles of the huemerus.
