158 



PRACTICAL PHYSIOLOGY 



Next divide the skin over the upper part of the sternum and reflect 

 the left skin flap. 



Pass threads round the sternal ends of the left first and second ribs. 

 Tie these and divide the ribs between the threads arid the sternum. 

 Pull the ribs outwards by means of the threads, separate the inter- 

 costal muscles with the knife, and by cutting through the spinal 

 attachments of these ribs remove them. 



, 



GE 



FIG. 159. Dissection of the stellate ganglion (GE) and cardiac accelerators. The 

 inferior cervical ganglion (CL) and vago sympathetic (vs) are also shown. (Pn) vagus; 

 (ac) carotid artery ; (asc) subclavion artery. (Dubois.) 



The stellate or first thoracic ganglion may now be found and cleaned 

 from the surrounding adipose tissue. It lies just in front of the spinal 

 attachment of the first rib. Branches enter the stellate ganglion from 

 the first, second, and third thoracic roots. Below the sympathetic 

 cord is attached to it, and above a nerve passes to it from the 8th 

 cervical root. The ganglion sends off branches, which form the 

 annulus of Vieussens, and pass to the inferior cervical ganglion. From 

 the annulus and from the inferior cervical ganglion branches pass to 

 the cardiac plexus. The stellate ganglion is the cell-station of these 

 accelerator and augmentor fibres. 



The stellate ganglion is also the cell station of the fibres which pass 

 to the brachial plexus (vasomotor, pilomotor, sudoriferous) and to the 

 vertebral artery. 



The cervical sympathetic fibres pass through the ganglion, and have 

 their cell-stations in the superior cervical sympathetic ganglion. 



Excitation of the (1) cervical sympathetic dilates the pupil, retracts 



