406 NERVOUS SYSTEM. 
Thoracic Portion of the Sympathetic (Fig. 157, page 381). 
—The inferior cervical ganglion (e) lies entirely within the 
thoracic cavity. It has the following branches: 
1. One or two small cardiac branches (4%), which pass to 
the heart (7). 
2. A large communicating branch (e’), which passes 
craniad from the cranial end of the ganglion (¢) along the 
lateral surface of the longus colli muscle, and gives communi- 
cating branches to the sixth, seventh, and eighth cervical 
nerves (V/, VI/, and V/IJ). 
3. One or two small communicating branches to the first 
thoracic nerve (/’). . 
4. A communicating branch to the second thoracic nerve. 
The arrangement of these communicating branches is 
somewhat variable; they may arise in various combinations, as 
at first united, or as more or less completely separated nerves. 
The sympathetic trunk (c) continues caudad from the caudal 
end of the inferior cervical ganglion, lying at first on the lateral 
surface’ of the longus colli, then on the lateral surface of the 
centra of the vertebra. For each vertebra there is a slight 
enlargement, forming one of the thoracic ganglia of the sym- 
pathetic, and from each ganglion one or two communicating 
branches are given off to the corresponding spinal nerve. Just 
caudad of the last rib (but while still in the thoracic cavity) 
the sympathetic gives off the large N. splanchnicus major or 
great splanchnic nerve (z), which passes ventrocaudad and 
pierces the diaphragm. The sympathetic itself then passes 
through the diaphragm laterad of the crus. 
Abdominal Portion of the Sympathetic (Fig. 164).—The 
great splanchnic nerve (4) passes through the diaphragm (2) 
laterad of the crus, extends two or three centimeters caudoven- 
trad, and joins a large ganglion lying just caudad of the cceliac 
artery (4), almost on the lateral surface of the superior mesen- 
teric (5). This is the celiac (or semilunar) ganglion (@). 
From it nerves branch in all directions, forming the ceeliac 
plexus (¢), a part of the large solar plexus. Less than a 
centimeter ventrocaudad of the cceliac ganglion, on the caudal 
surface of the superior mesenteric artery (5), is the somewhat 
