Forearm Joints and Ligaments

Question 1

Elbow Joint

Answer 1

• Formed by 2 articulations by humeroulnar articulation and humeroradial articulation
• Synovial hinge joint - only flex/ext
• Joint capsule is weak anteriorly and posteriorly, but is strengthened on each side by collateral ligaments

Question 2

Humeroulnar Articulation

Answer 2

Between the trochlea of humerus and trochlear notch of ulna

Question 3

Humeroradial Articulation

Answer 3

Between the capitulum of humerus and head of radius

Question 4

Collateral Ligaments

Answer 4

Strong, triangular bands that are medial and lateral thickening of fibrous layer of joint capsule

Question 5

Lateral Collateral Ligament

Answer 5

• Runs from lateral epicondyle of humerus to annular ligament of radius
• Helps prevent lateral dislocation of radius

Question 6

Ulnar Collateral Ligament

Answer 6

• Extends from medial epicondyle of humerus to coronoid process of ulna
• Consist of 3 bands: anterior (cordlike and is strongest), posterior (fan-like and weakest), oblique (serves to deepen socket for trochlea of humerus making joint more stable)
• Serves to prevent medial dislocation of ulna

Question 7

Annular Ligament of Radius

Answer 7

• Part of proximal radioulnar joint, but assists in stabilizing elbow joint by helping to prevent lateral dislocation of radius
• Attaches anteriorly and posteriorly to radial notch of ulna, completely encircling head of radius - adds stability to humeroradial part of articulation

Question 8

Proximal Radioulnar Joint

Answer 8

• Articulation: head of radius articulates with with radial notch of ulna
• Type: synovial pivot joint
• Movement: pronation and supination (head of radius rotates within cup-shaped annular ligament - radius rotates around fixed ulna)
• Ligaments: supposrted by annular ligament of radius and interosseous membrane

Question 9

Distal Radioulnar Joint

Answer 9

• Articulation: head of ulna articulates with ulnar notch on medial side of distal end of radius
• Type: synovial pivot joint
• Movements: pronation and supination (mvt occurs by distal end of radius rotating around head of ulna)
• Ligaments: anterior posterior ligaments, interosseous membrane, fibrocartilage disc helps to improve articulation by deepening of sockets on radius and ulna

Question 10

Cubital Fossa

Answer 10

• Shallow triangular depression in anterior surface of elbow
• 3 boundaries: imaginary line connecting medial/lateral epicondyles (superior), pronator teres (medial), brachioradialis (lateral)
• Floor of cubital fossa is made up of brachialis and supinator
• Roof is made up of fascia, biciptal aponeurosis, subcutaneous tissue, skin

Question 11

Anatomical Snuff Box

Answer 11

• Visible as hollow on lateral aspect of wrist when thumb is fully extended
• Draws abductor pollicus longus, extensor pollicus brevis, and extensor pollicus longus tendons in and produces concavity between them
• Anterior boundary=tendons of the APL and EPB
• Posterior boundary= tendon of EPL
• Floor= radial artery, trapezium and scaphoid bones