Extensor Carpi Ulnaris – Attachments, Action & Innervation

Author: Scott A. Sheffield MS

Last update:

Extensor carpi ulnaris is one of the muscles that comprise the superficial part of the posterior forearm compartment.

image descriptionExtensor Carpi Ulnaris

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, Extensor Carpi Radialis Brevis, Flexor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Carpi Ulnaris (highlighted in green) 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, Extensor Carpi Radialis Brevis, Anconeus, Flexor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Carpi Ulnaris (highlighted in green) 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 Carpi Ulnaris (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 Carpi Ulnaris muscle.
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image descriptionAttachments of the Extensor Carpi Ulnaris Muscle: Origin and Insertion

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

Insertion (distal attachment)
a. Base of 5th metacarpal (dorsal surface).

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, Extensor Carpi Radialis Brevis, Flexor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Carpi Ulnaris (highlighted in green) and Extensor Retinaculum.
A posterior view of the forearm showing the bony elements and isolated Extensor Carpi Ulnaris muscle.
A dorsal view of the forearm showing the bony elements and the attachments of the Extensor Carpi Radialis Longus muscle. The origin at the lateral epicondyle of the humerus. is marked by a red circle and the insertion at the base of 5th metacarpal (dorsal surface) is marked by a blue circle.
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Actions of the Extensor Carpi Ulnaris Muscle:

a.  image descriptionExtends hand at the wrist.

Muscle anatomy is hard! Simplify your studies with this upper limb muscle anatomy reference chart.

b.  image descriptionUlnar deviates (adducts) hand at the wrist.

Nerve to the Extensor Carpi Ulnaris muscle and its spinal segment:

a. 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 1-4. The answers in the box below are as follows 1. Flexor Carpi Ulnaris 2. Extensor Digiti Minimi 3. Extensor Carpi Ulnaris 4. 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. Flexor Carpi Ulnaris 2. Extensor 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 Carpi Ulnaris 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 Carpi Ulnaris muscle numbered 1.
A test yourself image of the dorsal view of the forearm showing the bony elements and the attachments of the Extensor Carpi Radialis Longus muscle. The origin at the lateral epicondyle of the humerus. is marked by a red circle and the insertion at the base of 5th metacarpal (dorsal surface) is marked by a blue circle.
Test yourself while observing the Extensor Carpi Ulnaris muscle
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