The Elbow and Radioulnar Joints

1
The Elbow and Radioulnar Joints

2
Bones

• Humerus
• trochlea of the humerus
• capitulum spherical knob on lateral side
• medial and lateral epicondyle
• Ulnar
• Trochlear notch of ulna
• Olecranon Process on posterior aspect
• radial notch
• coronoid process
• ulnar tuberosity
• Radius
• Head
• radial tuberosity

3
The Elbow Joint

• Classified as a ginglymus (hinge) joint
• The ELBOW consists of 2 joints
• humeroulnar
• olecranon process of the ulnar
• distal aspect of humerus
• radiohumeral
• radial head has small amount of articulation with
  humerus (capitulum)

4
Proximal Radioulnar Joint

• Proximal radioulnar joint
• articulation between radius and ulnar
• not part of hinge joint
• trochoid (pivot) joint
• allows for forearm pronation/supination

5
Movements

• Elbow
• Flexion
• Extension
• Forearm movements about the Proximal Radioulnar
  joint
• Supination Lateral rotation
• Pronation Medial Rotation

6
Muscles

• Posterior
• Triceps brachii
• Anconeus
• Supinator

• Anterior
• Biceps brachii
• Brachialis
• Brachioradialis
• Pronator teres
• Pronator quadratus

7
Muscles

• Elbow Flexors
• biceps brachii
• brachialis
• brachioradialis
• pronator teres

8
Muscles

• Elbow Extensors
• triceps brachii
• anconeus
• Forearm Pronators
• pronator teres
• pronator quadratus
• brachioradialis

9
Muscles

• Forarm Supinators
• supinator
• biceps brachii
• brachioradialis

10
Anconeus (p56)

• Origin
• posterior surface of lateral epicondyle of
  humerus
• Insertion
• ulna, posterior surface of olecranon process
• Action
• elbow extension

11
Biceps Brachii (p 57)

• Origin
• long head supraglenoid tubercle
• short head coracoid process
• Insertion
• radial tuberosity
• Action elbow flexion, supination, (weak shoulder
  flexor)

12
Brachialis (p58)

• Origin
• Lower portion of anterior surface of humerus
• Insertion
• coronoid process of ulna
• ulna tuberosity
• Action
• elbow flexion (true flexor)

13
Brachioradialis (p59)

• Origin
• upper 2/3 of lateral supracondylar ridge of
  humerus
• Insertion
• styloid process of radius
• Action
• elbow flexion
• supination (from pronated position to neutral)
• pronation (from supinated position to neutral)

14
Pronator Quadratus (p60)

• Origin
• ulna, anterior-distal fourth aspect
• Insertion
• radius, anterior-distal fourth
• Action
• pronation

15
Pronator teres (p61)

• Origin
• humerus, medial epicondyle
• ulna, cornoid process
• Insertion
• radius, middle third, lateral surface
• Action
• pronation
• elbow flexor

16
Supinator (p62)

• Origin
• Humerus, lateral epicondyle
• Ulna, supinator crest of ulna
• Insertion
• radius, lateral surface, upper 1/3
• Action
• supination

17
Triceps Brachii (p63)

• Origin
• long head scapula, infraglenoid tubercle
• lateral head humerus, 1/3 lagteral-posterior
  surface
• medial head humerus, lower 3/4 of posterior
  surface
• Insertion
• olecranon process of ulna
• Action
• All heads elbow extension
• Long head arm extension, arm adduction

18
Summary

• Elbow and Proximal Radioulnar Joints
• Bones
• Humerus, ulna, radius
• Actions
• Elbow (about humeralulnar joint)
• flexion, extension
• Forearm (about Proximal Radioulnar joint)
• pronation, supination