2<)o Dot-fal Nerves. [Book IX, 



and in forming a large ganglion with the intercoftal 

 nerve. 



The dorfal nerves alfo give branches backwards to 

 the ftrong mufcles fituated on the fpine, and which 

 ferve to ere<5t the body. Their principal trunks ac- 

 company the intercoftal arteries in the groove at the 

 bottom of each rib, and are diftributed with them to 

 the fides and anterior parts of the thorax. The fix 

 lower dorfal nerves alfo give branches to the diaphragm 

 and abdomen. The twelfth joins the firft and fecond 

 of the lumbar, and beftows nerves on the quadratus 

 lumborum, pfoas, and iliacus internus. 



The firit and fecond of the lumbar nerves fend 

 branches which ioin with others from the thi*d and 

 fourth, and form a large nerve which paffes through 

 the .foramen thyroideum, and is fpent on the mufcles 

 and integuments at the infide of the thigh ; it is/called 

 the obturator or posterior crural nerve. By branches 

 from the four upper lumbar nerves is alfo formed the 



; anterior crural nerve, which paffes out of the abdo- 

 men under the ligament of Fallopius, and is diftributed 

 on the integuments and mufcles au the fore part of the 



' thigh. A branch of this nerve alfo attends the vena 

 iaphena to the foot. 



The fourth and fifth lumbar nerves contribute with 



" the three fuperior facral nerves ro form the largeft nerve 



. of the body, the fciatic. This nerve, after giving 

 nerves to the mufcles about the hips, paffes behind 

 the tuberofity of the ifchium, and then downwards, clofe 

 to the pofterior part of the] os femoris. Diftributing 

 nerves through its whole progrefs it runs down the 

 back part of the leg, and terminates in the fole of the 

 foot. The fourth, fifth, and fixth anterior faCral nerves 

 are' much fmaller than the fuperior, and are chiefly 

 * diftributed on the bladder, re&um, and anus. Small 



nerves 



