Subclavian loop (''ansa subclavia''), also known as Vieussens' ansa after French

anatomist Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

Raymond Vieussens Raymond Vieussens (ca. 1635 – 16 August 1715) was a French anatomist from Le Vigan. There is uncertainty regarding the exact year of Vieussens birth, with some sources placing it as late as 1641. He studied medicine at the University of Montpe ...

(1635-1715), is a

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the e ...

cord that is a connection between the middle and

inferior cervical ganglion The inferior cervical ganglion is situated between the base of the transverse process of the last cervical vertebra and the neck of the first rib, on the medial side of the costocervical artery. Its form is irregular; it is larger in size than the ...

which is commonly fused with the first thoracic ganglion and is then called the

stellate ganglion The stellate ganglion (or cervicothoracic ganglion) is a sympathetic ganglion formed by the fusion of the inferior cervical ganglion and the first thoracic (superior thoracic sympathetic) ganglion, which exists in 80% of people. Sometimes, the seco ...

. The subclavian ansa forms a loop around the

subclavian artery In human anatomy, the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplie ...

; whence its name. This communicating branch downwards anteromedial to the

vertebral artery The vertebral arteries are major arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry o ...

makes a loop around the

from anterior to posterior and then lies medially to the

internal thoracic artery In human anatomy, the internal thoracic artery (ITA), previously commonly known as the internal mammary artery (a name still common among surgeons), is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with on ...

respectively. Sometimes there are two communicating branches encompassing the

, one from anterior and the other from posterior.

References

Definition from Online Medical Dictionary
Subclavian loop {{Neuroanatomy-stub