Chapter 3 - Elbow and Forearm 1

• Radial tuberosity


  Point of attachment for the tendons of biceps brachii muscle

  
• Styloid process


  Provides attachment for the brachoradialis muscles and radial collateral ligament

  
• Located at the lateral aspect (thumb side) of the forearm

  
• Radius head


  • Disc-shaped head that articulates with the capitulum of the humerus and the radial notch of the ulna
• Parts of the radius

  • Proximal end
  • Head
  • Neck
  • Radial tuberosity
  • Distal end
  • Styloid process
  • Ulnar notch

  
• Located on the medial aspect (little-finger side) of the forearm

  
• Ulna is longer than radius
• Proximal end of ulna

  • Olecranon and coronoid process receive the trochlea of the humerus
• Ulna tuberosity


  Forms part of elbow joint, receives head of radius, attachment of biceps brachii, attachment of ulna collateral ligament

  
• Elbow joint


  • Type: hinge joint
  • Articulation occur at 2 places: 1. head of radius articulates with the capitulum of the humerus, 2. trochlear notch of the ulna articulates with trochlea of the humerus

  
• Ligaments of the elbow joint

  • Radial collateral ligament
  • Annular ligament
  • Ulnar collateral ligament

  
• Sites where ulna and radius connect

  • Interosseous membrane (intermediate)
  • Proximal radioulnar joint
  • Distal radioulnar joint
• Interosseous membrane


  • Comprises of two main components: 1. Thick tendinous central band of fibres, 2. A proximal band of reverse fibres
  • Functions: To stabilize the forearm in compressive loads, Limit or reducing the bending strain between the radius and ulna
• Proximal radioulnar joint


  A pivot joint, Strong annular ligament attached to the anterior and posterior margins of the notch

  
• Forearm movements


  • Flexion
  • Extension
  • Pronation
  • Supination
• Forearm flexors


  • Biceps brachii
  • Brachialis
  • Brachioradialis

  
• Forearm extensors


  • Triceps brachii
  • Anconeus

  
• Forearm pronators


  • Pronator teres
  • Pronator quadratus
• Forearm supinator


  Supinator
• Biceps brachii


  Origin: Long head – supraglenoid, Short head – coracoid process of scapula<|>Insertion: Radial tuberosity and bicipital aponeurosis<|>Action: 1. Flexes forearm at elbow joint, 2. Supinates forearm at radioulnar joint, 3. Flexes arm at shoulder joint<|>Innervation: Musculocutaneous nerve

  
• Brachialis


  Origin: Distal, anterior surface of humerus<|>Insertion: Ulnar tuberosity and coronoid process of ulna<|>Action: Flexes forearm at elbow joint<|>Innervation: Musculocutaneous and radial nerves

  
• Brachioradialis


  Origin: Lateral border of distal end of humerus<|>Insertion: Superior to styloid process of radius<|>Action: 1. Flexes forearm at elbow joint, 2. Supinates and pronates forearm at radioulnar joints to neutral position<|>Innervation: Radial nerve

  
• Triceps brachii


  Origin: Long head – infraglenoid tubercle, Lateral head – lateral and posterior surface of humerus, Medial head – entire posterior surface of humerus<|>Insertion: Olecranon of ulna<|>Action: 1. Extend forearm at elbow joint, 2. Extend arm at shoulder joint<|>Innervation: Radial nerve

  
• Anconeus


  Origin: Lateral epicondyle of humerus<|>Insertion: Olecranon and superior portion of shaft of ulna<|>Action: Extends forearm at elbow joint<|>Innervation: Radial nerve

  
• Pronator teres


  Origin: <|>Insertion: <|>Action: 1. Pronates forearm at radioulnar joints<|>Innervation: Median nerve
• Pronator quadratus


  Origin: Distal portion of shaft of ulna<|>Insertion: Distal portion of shaft of radius<|>Action: 1. Pronates forearm at radioulnar joints<|>Innervation: Median nerve

  
• Supinator


  Origin: Lateral epicondyle of humerus and supinator crest<|>Insertion: Lateral surface of proximal one-third of radius<|>Action: 1. Supinates forearm at radioulnar joints<|>Innervation: Median nerve