Bones of the forearm, Elbow & Joints of the forearm

Question 1

Bones of the Forearm

Answer 1

Ulna

Radius

Question 2

Ulna

Answer 2

• Medial bone of forearm
• Longer bone of the forearm
• Stabilising bone of the forearm
• Radius pivots upon the ulna
• Large proximal end designed to articulate with distal humerus & head of radius
• Head of the ulna is distal

Question 3

Radius

Answer 3

• Lateral bone of the forearm
• Shorter bone of the forearm
• More mobile bone of the forearm
• Pivots upon ulna to create pronation and supination
• Head is proximal
• Distal end enlarged for wrist articulation

Question 4

Interosseous Membrane

Answer 4

• Dense irregular connective tissue membrane
• Binds the ulnar and radius together
• Increases surface area available for muscle attachment
• Allows force transmission between radius and ulna
• Helps separate anterior and posterior compartments of forearm (infection control)
• Small proximal and distal openings allow neurovascular structures to pass

Question 5

Radius Bony parts

Answer 5

Proximal end

• head (for elbow & proximal distal radioulnar joint)
• radial neck (for annular ligament)
• radial tuberosity (muscle attachment)

Body of the radius

• Anterior, posterior and interosseous borders
• Anterior, posterior and lateral surfaces

Distal end

• ulnar notch (for distal radioulnar jt)
• radial styloid process
• dorsal tubercle (Lister’s tubercle)

Question 6

Ulna

Answer 6

Proximal end

• olecranon process (you lean on this)
• coronoid process
• trochlear notch (for elbow)
• radial notches (for proximal radioulnar jt)
• ulnar tuberosity (muscle attachment)
• supinator crest & fossa

Body of the ulna

• Anterior, posterior and interosseous borders
• Anterior, posterior and medial surfaces

Distal end

• ulnar head
• ulnar styloid process
• articular surface (for distal radioulnar joint)

Question 7

Elbow joints

Answer 7

-Permits only flexion/extension in sagittal plane

Humeroulnar joint - trochlea of the humerus articulates with the trochlear notch of the ulna
Humeroradial joint - capitulum of the humerus articulates with the head of the radius

Question 8

Elbow joint - Ligaments

Answer 8

-Laterally
Radial collateral ligament – lateral epicondyle of humerus to annular ligament
Annular ligament – encircles the radius & holds it in the radial notch of ulna

-Medially
Ulnar collateral ligament – medial epicondyle of humerus to olecranon and coronoid processes of ulna

Question 9

Elbow joint – movements/Nerve supply

Answer 9

Movements
-Flexion & extension

Nerve supply
-Articular branches of musculocutaneous, ulnar and radial nerves

Question 10

Bursa of the elbow

Answer 10

Subtendinous olecranon bursa – b/w olecranon and triceps tendon
Subcutaneous olecranon bursa – b/w olecranon and skin

The elbow joint has many bursa to allow structures to move over each other without friction

Question 11

Radioulnar Joints

Answer 11

Proximal radioulnar joint
Distal radioulnar joint

• Both are pivot type synovial joints
• Allow pronation and supination of the forearm
• To create these movements the radius pivots upon the ulna

Question 12

Proximal Radioulnar Joint

Answer 12

• Pivot type synovial joint
• Movements: Pronation & supination
• Head of the radius rotates/spins upon the radial notch on the lateral -aspect of ulna
• Held in position by the annular ligament

Nerve supply
-Musculocutaneous, Median and Radial nerves

Question 13

Distal Radioulnar Joint

Answer 13

• Pivot type synovial joint
• Movements: Pronation & supination
• Ulnar notch of the radius moves back and forth across the head of the ulna

Articular disc

• Binds the end of the radius and ulna together
• Separates this joint (and the ulna) from the wrist joint

Nerve supply (nociception & proprioception) 
-anterior and posterior interosseous nerves