6/5/2017 The Elbow and Radioulnar Joints 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 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) 1 6/5/2017 Proximal Radioulnar Joint Proximal radioulnar joint articulation between radius and ulnar not part of “hinge” joint trochoid (pivot) joint allows for forearm pronation/supination Movements Elbow Flexion Extension Forearm movements about the Proximal Radioulnar joint Supination: Lateral rotation Pronation: Medial Rotation Muscles Anterior Posterior Biceps brachii Triceps brachii Brachialis Anconeus Brachioradialis Supinator Pronator teres Pronator quadratus 2 6/5/2017 Muscles Elbow Flexors biceps brachii brachialis brachioradialis pronator teres Muscles Elbow Extensors triceps brachii anconeus Forearm Pronators pronator teres pronator quadratus brachioradialis* Muscles Forarm Supinators supinator biceps brachii brachioradialis* 3 6/5/2017 Anconeus (p56) Origin posterior surface of lateral epicondyle of humerus Insertion ulna, posterior surface of olecranon process Action elbow extension Biceps Brachii (p 57) Origin: long head: supraglenoid tubercle short head: coracoid process Insertion radial tuberosity Action: elbow flexion, supination, (weak shoulder flexor) Brachialis (p58) Origin Lower portion of anterior surface of humerus Insertion coronoid process of ulna ulna tuberosity Action elbow flexion (‘true’ flexor) 4 6/5/2017 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) Pronator Quadratus (p60) Origin ulna, anterior-distal fourth aspect Insertion radius, anterior-distal fourth Action pronation Pronator teres (p61) Origin humerus, medial epicondyle ulna, cornoid process Insertion radius, middle third, lateral surface Action pronation elbow flexor 5 6/5/2017 Supinator (p62) Origin Humerus, lateral epicondyle Ulna, supinator crest of ulna Insertion radius, lateral surface, upper 1/3 Action supination 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 Summary Elbow and Proximal Radioulnar Joints Bones Humerus, ulna, radius Actions Elbow (about humeralulnar joint) flexion, extension Forearm (about Proximal Radioulnar joint) pronation, supination 6.