Expert Opinion SCV
The SCV is fixed to the clavipectoral fascia avoiding anterior vessel wall collapse under the pressure of the approaching needle. In infants the SCV runs more cephalad than in older children having a nearly extrathoracic position before reaching the brachiocephalic vein (2). The whole length is therefore more easily visualised by US. Moreover the place where the SCV passes over the first rib has been identified as a safe spot for its cannulation (3). At that place, the first rib protects the lung from accidental puncture and from this place on the subclavian artery passes behind the anterior scalene muscle whereas the vein remains in front of it. The major disadvantage of this technique is that needle or i.v. cannula cannot be imaged via US while it is advanced under the clavicle due to the US shadow caused by the clavicle.