LOWER CEHVICAL GANGLION. 693 



chest it lies on the trachea, where it is joined by filaments of the recurrent 

 laryngeal nerve, and it ends in the right side of the deep cardiac plexus. 

 While in the neck, the nerve communicates with the upper cardiac nerve 

 and the recurrent branch of the pueumo-gastric. 



On the left side, the middle cardiac nerve enters the chest between the 

 left carotid and subclavian arteries, and joins the left side of the deep 

 cardiac plexus. 



AVhen the middle cervical ganglion is small, the middle cardiac nerve may be 

 found to be an offset of the inter-ganglionic cord. 



LOWER CERVICAL GANGLION". 



The lower or third cervical ganglion is irregular in shape, usually some- 

 what flattened and round or semiluuar, and is frequently united in part 

 to the first thoracic ganglion. Placed in a hollow between the transverse 

 process of the last cervical vertebra and the neck of the first rib, it is con- 

 cealed by the vertebral artery. It is connected by short communicating 

 cords with the two lowest cervical nerves. Numerous branches are given 

 oif from it, among which the largest is the lower cardiac nerve. 



THE LOWER CARDIAC NERVE, issuing from the third cervical ganglion or 

 from the first thoracic, inclines inwards on the right side, behind the sub- 

 clavian artery, and terminates in the cardiac plexus behind the arch of the 

 aorta. It communicates with the middle cardiac and recurrent laryngeal 

 nerves behind the subclavian artery. 



On the left side, the lower cardiac often becomes blended with the middle 

 cardiac nerve, and the cord resulting from their union terminates in the 

 deep cardiac plexus. 



BRANCHES TO BLOOD-VESSELS. From the lowest cervical and first dorsal 

 ganglia a few slender branches ascend along the vertebral artery in its 

 osseous canal, forming a plexus round the vessel by their inter-communica- 

 tions, and supplying it with offsets. This plexus is connected with the 

 cervical spinal nerves as far upwards as the fourth. 



One or two branches frequently pass from the lower cervical ganglion to 

 the first dorsal ganglion in front of the subclavian artery, forming loops 

 round the vessel (ansse Vieussenii), and supplying it with small offsets. 



THORACIC PART OF THE GANGLIATED CORD. 



In the thorax the gangliated cord is placed towards the side of the spinal 

 column, in a line passing over the heads of the ribs. It is covered by the 

 pleura, and crosses the intercostal blood-vessels. 



Opposite the head of each rib the cord usually presents a ganglion, 

 so that there are commonly twelve of these ; but, from, the occasional 

 coalescence of two, the number varies slightly. The first ganglion when 

 distinct is larger than the rest, and is of an elongated form ; but it is often 

 blended with the lower cervical ganglion. The rest are small, generally 

 oval, but very various in form. 



Connection with the spinal nerves. The branches of connection between 

 the spinal nerves and the ganglia of the sympathetic are usually two in 

 number for each ganglion ; one of these generally resembling the spinal 

 nerve in structure, the other more similar to the sympathetic nerve. 



BRANCHES OF THE GANGLIA. 



The branches furnished by the first fivt or six ganglia are small, and are 



