<unk>  (ansa<unk> , also known as Vieussens' ansa after French anatomist Raymond Vieussens (1635-1715), is a nerve cord that is a connection between the middle and inferior cervical ganglion which is commonly fused with the first thoracic ganglion and is then called the stellate ganglion. The<unk>  ansa forms a<unk>  around the<unk>  artery; whence its name. This communicating branch downwards anteromedial to the vertebral artery makes a<unk>  around the<unk>  artery from anterior to posterior and then lies medially to the internal thoracic artery respectively. Sometimes there are two communicating branches encompassing the vertebral artery, one from anterior and the other from posterior.
Subclavian loop
Subclavian triangle
Thoracic inlet
Posterior triangle of the neck
Boracic lint
Anterior triangle of the neck
Meckelian groove
Codman triangle