The origin of the høyre subclavian fra the innominate takes place, in some cases, above the sternoclavicular articulation, og occasionally, but less frequently, below that joint. Arterien may arise as a separate trunk fra aortabuen, og in such cases it may be either the first, andre, tredje, or even the last branch derived fra that vessel; in the majority, however, it er the first or last, rarely the andre or tredje. When it er the first branch, it occupies the ordinary position of the innominate arterie; when the andre or tredje, it gains its usual position by passing bak the høyre carotid; og when the last branch, it arises fra the venstre extremity of the arch, og passes obliquely toward the høyre side, usually bak the trachea, øsofagus, og høyre carotid, sometimes mellom the øsofagus og trachea, to the upper border of the first rib, whence it follows its ordinary course. In very rare instances, this vessel arises fra the thoracic aorta, as low down as the fourth thoracic vertebra. Occasionally, it perforates the Scalenus anterior; more rarely it passes in front of that muskel. Sometimes the vena subclavia passes with arterien bak the Scalenus anterior. Arterien may ascend as high as 4 cm. above kravebenet, or any intermediate point mellom this og the upper border of the bone, the høyre subclavian usually ascending higher than the venstre.