Joints of the elbow Flashcards Preview

Human Locomotor Systems > Joints of the elbow > Flashcards

Flashcards in Joints of the elbow Deck (17):
1

Describe the elbow joint.

- Compound joint between humerus, radius and ulna (more than 2 articular surfaces)
- Hinge joint
- Capsule houses two distinct joints: Elbow and proximal radioulnar
- No meniscus
- Supplied by branches of the brachial artery
- Innervated by musculocutaneous, radial and ulnar nerves.

2

What are the ligaments of the elbow joint?

1. Ulnar collateral ligaments: Anterior, posterior, oblique
2. Radial collateral ligaments: Blends with annular ligament
The strongest support comes from the medial collateral ligament
Articular capsule is lax anteriorly and posteriorly.

3

What is the purpose of the fat pads in the fossa?

They are in the olecranon, radial and coronoid fossa - they cushion movement and help spread synovial fluid

4

What are the movements at the elbow?

1. Flexion: This usually occurs between humerus and ulna. There is radial contact in a close-packed position (90 degree flexion and mid-way between pronation/supination)

2. Extension: Occurs at an oblique angle of the trochlea. There is no hyperextension because of the olecranon.
Carrying angle: Elbow extension, forearm supination. It is greater in adults than children and is greater in females than males.

5

Which muscles allow flexion at the elbow joint?

- Biceps brachii
- Brachialis
- Brachioradialis

6

Which muscles allow extension at the elbow joint?

- Triceps brachii
- Anconeus

7

Describe the radioulnar joints.

- They occur at each end of the radius, thus proximal and distal radioulnar joints.
- Between radial notch on ulna and ulnar notch on radius
- Fracture at one end may lead to dislocation at the other

8

What is the purpose of the interosseous membrane?

It transmits forces from radius to ulna and eventually to the humerus. At the proximal end, only 20% through radius and at the distal end 80% thorough the radius.
It tightens as the joint undergoes pronation.

9

Describe the proximal radioulnar joint.

- It is between the head of radius and radial notch of ulna.
- It is a pivot, synovial joint.
- it is within the elbow joint capsule
- It has a sacciform recess in which the synovial membrane extends downwards.
- It is innervated by the median, musculocutaneous and radial nerves
- It is supplied by the branches of deep radial and radial arteries.

10

What are the ligaments of the proximal radioulnar joint?

- Annular ligament
- Quadrate ligament
- Interosseous membrane

11

Describe the distal radioulnar joint.

- It is between the head of ulna and ulnar notch on radius
- It is a pivot type synovial joint
- It is supported by anterior and posterior ligaments
- An articular disc sits between the bones and progresses to distalmost face of ulna
- Innervated by Median and rdial interosseous nerves
- Supplied by anterior and posterior interosseous arteries

12

What are the movements at the radioulnar joints?

- Pronation/supination, working with flexion/extension
- Midprone position most stable

13

What are the muscles moving the radioulnar joints?

- Pronation: Pronator teres, pronator quadratus. Assisted by FCR, PL, Brachioradialis

-Supination: Supinator, biceps brachii. Assisted by EPL, ECRL

14

Dislocaiton of the proximal radioulnar joint

- May cause annular ligament laxity in children
- Radial head is displaced as muscles pull radial head superiorly.
- There will be reduced capacity to carry out some movements e.g - supinate forearm, push proximally and flex joint.

15

What are the clinical considerations at the H-U and R-U joints?

- Bursitis
- Epicondylisits
- Avulsion fractures: Medial epicondyle of humerus; olecranon/coronoid process/styloid process of ulna.
- Supracondylar fracture of humerus - Volkmann's ishchemic contracture.

16

What is a valgus deformity?

In terms of dislocation at the elbow, it is when the distal joint is lateral to the proximal joint.

17

What is a varus deformity?

In terms of dislocation at the elbow, it is when the distal joint is medial to the proximal joint.