Joints

Question 1

Classify the elbow (humero-ulnar) joint

Answer 1

Synovial hinge joint (uniaxial), capable of one degree of freedom

Question 2

Briefly describe the articular surfaces of the humero-ulna articulation

Answer 2

The humerus has a trochlear which articulates with the trochlear notch of ulna.

The trochlea surface is concave from side to side but convex from front to back. The medial part of the trochlea extends downwards to a lower level than the lateral sides.

The trochlear notch has a rounded curved, longitudinal ridge extending from the tip of the olecranon to the tip of the coronoid process, which fits the groove of the trochlea.

All articular surfaces are covered in hyaline cartilage.

Question 3

Classify humero-radial joint

Answer 3

Modified synovial ball & socket joint

Question 4

Briefly describe the articular surfaces of the humero-radial articulation

Answer 4

The head of the radius articulates with the capitulum of the humerus.

The head of the radius is concave with continuous convex cartilage around the sides and is thickest on the middle of the concavity.

The capitulum is a bony hemisphere on the anterior inferior surface of the distal humerus.

All articular surfaces are covered in hyaline cartilage.

Question 5

Name the ligaments which support the elbow joint

Answer 5

Lateral (Radial) collateral ligament

medial (Ulnar) collateral ligament

Question 6

Name the movements that occur at the elbow joint

Answer 6

Flexion and Extension

Question 7

Classify superior and inferior radio-ulnar joints

Answer 7

Synovial pivot joint, uniaxial - capable of 1 degree of freedom

Question 8

Briefly describe the articular surfaces of the superior radio-ulnar joint

Answer 8

Circular and convex Head of proximal radius id received by the reciprocally concave radial notch of proximal ulna

Only one-fifth of radial notch articulates with radial head - annular ligament surrounds the radial head and holds it tight against the radial fossa of ulna

Included in elbow joint capsule

All articular surface covered with hyaline cartilage

Question 9

Name ligaments of superior radio-ulnar joint

Answer 9

Annular ligament

Quadrate ligament

Question 10

State attachments of elbow joint capsule

Answer 10

attaches around the edge of the ulnar articular surfaces including the radial notch

Encompasses humero-ulnar, humero-radial and superior radio-ulnar joints

Synovial membrane - originates from the edges of the articular cartilage and lines the radial fossa, the coronoid fossa, the olecranon fossa, the deep surface of the joint capsule, and the medial surface of the trochlea

Fibrous layer - thickened medially and laterally to form collateral ligaments
support the flexion and extension movements of the elbow joint

Question 11

Classify the inferior radio-ulnar joint

Answer 11

Synovial pivot joint

Uniaxial - capable of 1 degree of freedom

Question 12

Briefly describe the articular surfaces of the inferior radio-ulnar joint

Answer 12

Between crescent-shaped convex distal head of ulna and the concave ulnar notch of distal radius.
Both surfaces are lined by the hyaline cartilage.
Also contains triangular fibrocartilage complex (TFCC) - Separates the inferior RUJ from the wrist joint

Question 13

Give attachments of the triangular fibrocartilage complex (TFCC)

Answer 13

apex - lateral surface of the styloid process of ulna

base - inferior margin of the ulnar notch of radius

Question 14

Give attachments of the inferior radio-ulnar joint capsule

Answer 14

fibrous capsule that attaches to the margins of the articular surfaces

synovial membrane projects superiorly to the interosseous space between the radius and ulna, extending beyond the joint capsule (recessus sacciformis/saccular recess)

Question 15

Classify the middle radio-ulnar joint

Answer 15

Fibrous syndesmosis

Joint also known as interosseous membrane

Question 16

Briefly describe the articular surfaces of the middle radio-ulnar joint

Answer 16

Attaches to medial and lateral borders of the radius and ulna, respectively

2 layers in perpendicular directions - adds tension; helps transfer force from radius to ulnar thus from hand to humerus

Question 17

Describe function of the middle radio-ulnar joint (interosseous membrane)

Answer 17

Two hiatus for transmission of neurovascular bundles

Serves as an attachment for deep muscles of forearm

Stabilises Radius and Ulna - prevents disruption between bones

Question 18

State attachments and functions of the medial (ulnar) & lateral (radial) collateral ligaments

Answer 18

Capsular ligaments - support flexion and extension movements of the elbow joint

• Radial (lateral) collateral ligament
○ single triangular thickened band from the lateral epicondyle of humerus to the annular ligament
○ Does not attach directly to radial head, allowing it to pivot
○ Prevents varus strain (ADD) of elbow

• Ulna (medial) collateral ligament
○ thick triangular band, which fans out from the medial epicondyle of humerus and has anterior, posterior, intermediate and transverse bands inserting onto the medial aspect of the coronoid process and olecranon of ulna
○ Prevents valgus strain (ABD) of elbow

Question 19

State attachments and function of annular ligament

Answer 19

forms a ring that surrounds the radial head, attaching to the anterior and posterior margins of the radial notch of the ulna

Stabilises proximal RUJ

Inferior diameter is smaller - providing a tight fit about the neck of the radius

Inner surface lined with fibrocartilage - facilitating free rotation of radial head

Question 20

State attachments and function of the quadrate ligament

Answer 20

Small ligament arising from the inferior border of the radial notch to the neck of radius

Tested by full pronation and full supination - sufficient laxity to allow for full pronation/supination but tension occurs preventing over pronation/supination

Question 21

State function the olecranon bursa

Answer 21

Facilitates smooth movement of the skin over Olecranon process during flexion/extension

Bursitis - infection/inflammation, e.g. lorry drivers leaning elbow on window w/ constant vibrations for a prolonged period