Lab 4 - Module 1 - Extensor Compartments of the Arm and Forearm: Page 5 of 9
Superficial Extensor Muscles
| Add the Extensor Digiti Minimi muscle. |
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Origin - Lateral epicondyle of the humerus
Insertion - Dorsal digital expansion of the 5th metacarpal Innervation - Posterior Interosseous Nerve from the deep branch of the radial nerve Action - Extends the little finger and the hand Blood supply - Radial and posterior interosseous arteries. |
| Add the Extensor Carpi Ulnaris muscle. |
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Origin - Lateral epicondyle of the humerus and posterior border of ulna
Insertion - Medial side of the base of the 5th metacarpal Innervation - Posterior Interosseous Nerve from the deep branch of the radial nerve Action - Ulnar deviation and extension of wrist Blood supply - Radial and posterior interosseous arteries. |
| Add the Extensor Digitorum muscle. |
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Origin - Lateral epicondyle of the humerus
Insertion - Dorsal aspect of the middle and distal phalanges of the four fingers Innervation - Posterior Interosseous Nerve from the deep branch of the radial nerve Action - Extends the fingers and the hand Blood supply - Radial and posterior interosseous arteries. |
| Add the Extensor Carpi Radialis Brevis muscle. |
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Origin - Lateral epicondyle of the humerus
Insertion - Dorsal surface of the base of the 3rd metacarpal Innervation - Deep Radial Nerve Action - Radial deviation and wrist extension Blood supply - Radial and posterior interosseous arteries. |
| Add the Extensor Carpi Radialis Longus muscle. |
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Origin - Distal lateral 1/3rd of the supracondylar ridge of humerus
Insertion - Dorsal surface of the base of the 2nd metacarpal Innervation - Radial Nerve Action - Radial deviation and wrist extension Blood supply - Radial and posterior interosseous arteries. |
| Add the Brachioradialis muscle. |
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Origin - Proximal 2/3rds of lateral supracondylar ridge of humerus
Insertion - Lateral aspect of the base of the styloid process of the radius Innervation - Radial Nerve Action - Flexes the forearm when forearm is semi-pronated Blood supply - Radial and posterior interosseous arteries. |
| This completes the superficial extensor muscles. |