Description
The ansa subclavia refers to the neuronal branch of the cervicothoracic ganglion (inferior cervical or stellate ganglion) that loops underneath the subclavian artery and reconnects with the middle cervical sympathetic ganglion (Elias, 2000).
Fibers from the ansa subclavia give rise to the inferior cervical cardiac nerves, which arise from the medial aspect of the cervicothoracic ganglion and descend along the subclavian artery to join the cardiac plexus. Stimulation of the ansa subclavia results in chronotropic and inotropic responses of the heart to increased heart rate, contractility, and blood pressure.
There are variable branches that originate from either the ansa subclavia or the middle cervical ganglion and form anastomoses with the recurrent laryngeal nerve or phrenic nerve. Communicating branches are sometimes given to the vagus nerve.
Related parts of the anatomy
References
Elias, M. (2000) Cervical sympathetic and stellate ganglion blocks. Pain Physician, 3(3), 294-304.
