• Extensor Digitorum Communis is a long muscle with one origin and multiple insertions.

• It is present at the back of the Forearm between Extensor Carpi Ulnaris and Extensor Carpi Radialis Muscles.

ATTACHMENTS

Extensor Digitorum Communis has following origin and insertions:

• Origin : It arises from the Lateral Epicondyle of the Humerus via a common extensor tendon.

• It runs downwards and divides into four parts.

• Insertion : Extensor Digitorum Communis gets inserted into the Extensor Expansion and via it to the posterior surface of the medial four Phalanges.

The tendon of this muscle divides several times, at different levels (at the level of metacarpophalangeal joint and interphalangeal joint) before it can insert into its final destination. Result is the formation of a net like structure on the back of hand. That’s why this muscle is given the name of extensor expansion.

BLOOD SUPPLY 

It is supplied in most part by Posterior Interosseous Artery.

NERVE SUPPLY

Extensor Digitorum Communis is innervated via Radial Nerve.

ACTION

Contraction of Extensor Digitorum Communis causes extension of the Wrist joint and all 4 medial Phalanges.

CLINICAL POINTS

Any isolated damage or injury to this muscle is quite rate. However, a rare condition associated with extensor digitorum is called isolated compartment syndrome. This condition is characterized by excessive swelling, pain and poor perfusion of tissues. The swelling is enhanced to such degree that it starts to hamper the supply of blood to tissues causing tissue death.