The Elbow

Question 1

Classify the Elbow Joint

Answer 1

synovial, compound, uniaxial, hinge joint

Question 2

Describe the articular surfaces of the elbow joint

Answer 2

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

Question 3

what is normal carrying elbow of the elbow?

Answer 3

5 to 15 degrees

Question 4

Describe the joint capsule of the elbow

Answer 4

• 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

Question 5

what reinforces the joint capsule?

Answer 5

strong collateral ligaments

- weak anteriorly and posteriorly -

Question 6

Describe the synovial membrane of the elbow joint

Answer 6

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,

Question 7

Shape of Ulnar Collateral Ligamnet

Answer 7

Thick anterior and posterior bands with thin intermediate portion

Question 8

Shape of Radial collateral ligament

Answer 8

Strong triangular band

Blends with annular ligament

Question 9

Shape of Quadrate ligament

Answer 9

Fibres run in criss-cross manner – to cause constant tension on ligament

Question 10

Shape of Annular Ligament

Answer 10

Thick ring like band

Question 11

Attachments of Ulnar collateral ligament

Answer 11

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.

Question 12

function of ulnar collateral ligamnet

Answer 12

Prevents excessive valgus movement

Question 13

Attachments of Radial Collateral Ligamnet

Answer 13

O: anteroinferior lateral epicondyle

I: margins of radial notch of the ulna

Question 14

Function of radial collateral ligamnet

Answer 14

Prevents excessive varus movement

Question 15

Attachments of annular ligamnet

Answer 15

O: Anterior margins of radial notch of ulna

Encircle the head and neck of radius

I: posterior margins of radial notch of ulna

Question 16

Function of the annular ligament

Answer 16

Anchors the head of the radius within the joint and facilitates movement.

Question 17

Attachment of the quadrate ligament

Answer 17

O: lower border of radial notch of ulna

I: adjacent medial surface of neck of radius – proximal to radial tuberosity

Question 18

Function of the Quadrate ligament

Answer 18

Maintain stability of the superior radioulnar joint during pronation and supernation.

Question 19

Nerve supply to the elbow joint

Answer 19

twigs from musculocutaneous, medial and radial nerves anteriorly, and ulnar and radial nerves posteriorly – C5-C8

Question 20

what are the stabilising factors of the elbow joint?

Answer 20

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.