Bones of the forearm, Elbow & Joints of the forearm

Ulna Radius

• 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

• 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

• 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

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)

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)

-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

-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

Movements -Flexion & extension Nerve supply -Articular branches of musculocutaneous, ulnar and radial nerves

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

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

• 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

• 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