452 



SYMPATHETIC NERVE. 



pearance. The lower cervical ganglion pre- 

 sents an irregularly oblong shape, about ith 

 of an inch in length and T '^th of an inch in 

 thickness, and still has the appearance of being 

 pro'onged downwards into the first thoracic 

 ganglion. The thoracic ganglia are much 

 smaller, measuring about th of an inch ; and 

 are more or less triangular in shape, present- 

 ing the lobulated aspect above described. The 

 connecting cord between the different ganglia 

 has a reddish grey colour, is flattened, mea- 

 suring about Tvijth of an inch in breadth, and 

 presents the appearance of consisting of dis- 

 tinct bundles of fibres. A portion of these 

 can be traced over the surface of the ganglia, 

 others appear to sink into them, while a con- 

 siderable number can be traced into the rami 

 communicantes. The latter are very distinct; 

 some of them in the thoracic region appear to 

 be almost as thick as the cord of the S3'inpa- 

 thetic itself, and all of them present the same 

 greyish red appearance. On turning inwards 

 to the sympathetic, many of their fibres are 

 seen to be prolonged into the main cord of 

 the sympathetic, and merely run along the 

 sides of the corresponding ganglia : these pass 

 both upwards towards the head, and down- 

 wards in the direction of the pelvis. They 

 join the spinal nerves at the point where the 

 anterior and posterior roots become united 

 into a common trunk. By far the greater 

 portion of the fibres in the rami communi- 

 cantes run inwards towards the spinal cord. 



The splanchnic nerve, which is about |th 

 of a line in thickness, has a whiter aspect than 

 the main cord of the sympathetic. 



The nerves on the surface of the heart are 

 very numerous and distinct, presenting the 

 same arrangement as has been already de- 

 scribed. The cceliac and epigastric plexuses 

 are also large ; the latter containing several 

 ganglia. There are also several small ganglia 

 in the plexus upon the abdominal aorta. 



The ganglia on the cerebral and spinal 

 nerves present much the same appearance as 

 those in the animal after birth, only they are 

 softer and have a redder colour. 



As regards the development of the sympa- 

 thetic in the human subject, it would appear 

 from the observations of Lobstein*, that in 

 the embryo of the 14th week, about three 

 inches in length, the main cord of the nerve 

 was very apparent. In the chest it constituted 

 a thick cord of a red colour, the ganglia being 

 closely approximated towards one another. 

 The superior cervical ganglion was very well 

 formed, and about two lines in length, and half 

 aline in thickness. The great splanchnic nerve 

 existed as a very delicate filament : the semi- 

 lunar ganglia were almost imperceptible. 



In an embryo male, about five months, old 

 and measuring six inches in length, Lobstein 

 found the trunk of the sympathetic very dis- 

 tinctly developed. It constituted an uninter- 

 rupted cord extending from the base of the 

 cranium to the pelvis. The superior cervical 



* De Nervi Lympathici humani fabrica, usu, et 

 rnorbis, cap. iii. p. 47. 



ganglion was rounder than in the adult : it 

 was three lines in length, and about half a 

 line in thickness. The greater splanchnic 

 nerve was very distinct, but very delicate, and 

 arose by three roots. The semilunar ganglia 

 were small, indistinct, and measured only 

 about half a line in their greatest diameter. 

 They were adherent to the supra-renal cap- 

 sule and to the vessels. The thoracic ganglia, 

 with the exception of the first, constituted 

 little enlargements about half a line thick. 

 According to Kiesselbach, the solar ganglia do 

 not make their appearance until about the 

 7th month. At the 5th month, he found the 

 ophthalmic and submaxillary ganglia formed ; 

 and about the 6th month, the spheno-palatine 

 ganglion appears ; and in the 5th month, ac- 

 cording to the same author, the communi- 

 cating branches between the sympathetic and 

 cerebro-spinal system appear. 



In the foetus of eight months, the superior 

 cervical ganglion, according to Lobstein, mea- 

 sures about five lines in length, and a line and 

 a half in breadth. The greater splanchnic nerve 

 is very distinct, but very fine, and terminates 

 in ?n imperfect semi-lunar ganglion. 



In the foetus, at the full period, the superior 

 cervical ganglion, according to Lobstein, mea- 

 sures about 8^ lines in length, and furnishes 

 four filaments to the branches of the external 

 carotid, while a fifth is lost on the crico- 

 thyroid artery. The thoracic ganglia are well 

 formed, and measure about a line in diameter, 

 with the exception of the first, which mea- 

 sures about 5 lines. They are of a red 

 colour ; and nearly all of them receive two 

 branches from the intercostal nerves. The 

 trunk of the sympathetic is very thick; the 

 interval between the ganglia is about ith of a 

 line. The lumbar ganglia are very apparent. 

 The semilunar ganglia are of small size com- 

 pared with the other ganglia. Lobstein failed 

 to find the coccygeal ganglion in the child 

 immediately after birth; according to Kiessel- 

 bach, on the other hand, it appears about the 

 fifth month. 



Fig. 298. 



c 







<? 

 



A, ganglionic corpuscles from the Gasserian 

 ganglion of a calf 1 J inch in length ; B, nerve-fibres 

 from the same; c, from one of the thoracic ganglia 

 of the sympathetic in the same animal. 



With respect to the minute structure of 

 the ganglia and nerves in the foetus, the Gas- 

 serian ganglion in the foetal calf, H inch in 

 length, consists of the following elements : 

 1st, bodies measuring from the ^oVo*' 1 to the 



