Extensor Digitorum Muscle

Author: Scott A. Sheffield MS

Last update:

The extensor digitorum muscle is one of the muscles in the posterior compartment of the forearm.

image descriptionExtensor Digitorum Muscle

A posterior view of the forearm showing the bony elements and the deeper muscles. The visible, labelled muscles are as follows: Triceps Brachii, Brachioradialis, Extensor Carpi Radialis Longus, Anconeus, Extensor Digitorum (highlighted in green), Extensor Carpi Radialis Brevis, Flexor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Carpi Ulnaris and Extensor Retinaculum.
A posterior view of the forearm showing the bony elements and the deeper muscles. The visible, labelled muscles are as follows: Extensor Digitorum (highlighted in green), Extensor Carpi Radialis Brevis, Flexor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Carpi Ulnaris and Extensor Retinaculum.
A posterior view of the forearm showing the bony elements and the deeper muscles. The visible, labelled muscles are as follows: Supinator, Extensor Digitorum (highlighted in green), Abductor Pollicis Longus, Extensor Pollicis Longus, Extensor Pollicis Brevis, Extensor Indicis and Extensor Retinaculum.
A posterior view of the forearm showing the bony elements and isolated Extensor Digitorum muscle.
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image descriptionAttachments of Extensor Digitorum Muscle: Origin and Insertion

Origin (proximal attachment)
a. Lateral epicondyle of humerus.

Insertion (distal attachment)
a. Distal phalanges via dorsal mechanism of digits 2-5 (extensor expansion).

A posterior view of the forearm showing the bony elements and the deeper muscles. The visible, labelled muscles are as follows: Triceps Brachii, Brachioradialis, Extensor Carpi Radialis Longus, Anconeus, Extensor Digitorum (highlighted in green), Extensor Carpi Radialis Brevis, Flexor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Carpi Ulnaris and Extensor Retinaculum.
A posterior view of the forearm showing the bony elements and isolated Extensor Digitorum muscle.
A dorsal view of the forearm showing the bony elements and the attachments of the Extensor Digitorum muscle. The origin at the lateral epicondyle of humerus. is marked by a red oval and the insertions at the distal phalanges via dorsal mechanism of digits 2-5 (extensor expansion) are marked by blue circles. The attachment sites are connected by a transparent Extensor Digitorum muscle.
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Actions of the Extensor Digitorum muscle on the wrist:

a. image descriptionExtends the wrist.

Need a hand learning the anatomy of the forearm extensors? Look no further than these quizzes and diagram labelling exercises. 

a. image descriptionExtends the fingers (middle phalanx of digits 2-5).

Nerve to the Extensor Digitorum muscle and its spinal segment:

a. Deep branch of radial nerve (C6, C8).

An overview of the posterior forearm muscles:

A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-10 and the answers in the box below are concealed.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-10. The answers in the box below are as follows 1. Triceps Brachii 2. Brachioradialis 3. Extensor Carpi Radialis Longus 4. Anconeus 5. Extensor Digitorum 6. Extensor Carpi Radialis Brevis 7. Flexor Carpi Ulnaris 8. Extensor Digiti Minimi 9. Extensor Carpi Ulnaris 10. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-9. The answers in the box below are as follows 1. Brachioradialis 2. Extensor Carpi Radialis Longus 3. Anconeus 4. Extensor Digitorum 5. Extensor Carpi Radialis Brevis 6. Flexor Carpi Ulnaris 7. Extensor Digiti Minimi 8. Extensor Carpi Ulnaris 9. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-8. The answers in the box below are as follows 1. Extensor Carpi Radialis Longus 2. Anconeus 3. Extensor Digitorum 4. Extensor Carpi Radialis Brevis 5. Flexor Carpi Ulnaris 6. Extensor Digiti Minimi 7. Extensor Carpi Ulnaris 8. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-7. The answers in the box below are as follows 1. Anconeus 2. Extensor Digitorum 3. Extensor Carpi Radialis Brevis 4. Flexor Carpi Ulnaris 5. Extensor Digiti Minimi 6. Extensor Carpi Ulnaris 7. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-6. The answers in the box below are as follows 1. Extensor Digitorum 2. Extensor Carpi Radialis Brevis 3. Flexor Carpi Ulnaris 4. Extensor Digiti Minimi 5. Extensor Carpi Ulnaris 6. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-5. The answers in the box below are as follows 1. Extensor Digitorum 2. Flexor Carpi Ulnaris 3. Extensor Digiti Minimi 4. Extensor Carpi Ulnaris 5. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-3. The answers in the box below are as follows 1. Extensor Digitorum 2. Flexor Carpi Ulnaris 3. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the deeper muscles. The visible muscles of the forearm are numbered 1-7. The answers in the box below are as follows 1. Supinator 2. Extensor Digitorum 3. Abductor Pollicis Longus 4. Extensor Pollicis Longus 5. Extensor Pollicis Brevis 6. Extensor Indicis 7. Extensor Retinaculum.
A test yourself image of the dorsal view of the forearm showing the bony elements and the isolated Extensor Digitorum muscle numbered 1.
A test yourself image of the dorsal view of the forearm showing the bony elements and the attachments of the Extensor Digitorum muscle. The origin at the lateral epicondyle of humerus. is marked by a red oval and the insertions at the distal phalanges via dorsal mechanism of digits 2-5 (extensor expansion) are marked by blue circles. The attachment sites are connected by a transparent Extensor Digitorum muscle.
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Muscles That Act On The Posterior Wrist & Hand

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