The Occipital artery
is a posterior branch of the external carotid artery. The occipital artery
is widespread in its distribution to the head, giving off meningeal branches
to the posterior cranial fossa, and muscular branches to the sternocleidomastoid
and other posterior muscles.
When the external carotid or subclavian arteries are ligated or obstructed, collateral circulation is provided by the descending branch of the occipital artery.