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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)

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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

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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*

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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)

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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

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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

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