1236 



HUMAN ANATOMY. 



with the ophthalmic nerve, the spheno-palatine with the maxillary and the otic and 

 submaxillary with the mandibular. Each is the recipient of three roots — a motor, a 

 sensory and a sympathetic — and from each ganglion branches are given off to more or 

 less contiguous structures. 



The significance of these bodies— whether of the nature of spinal or sympathetic 

 ganglia— has long been a subject of discussion. The close resemblance of their 

 nerve-cells to the stellate neurones of undoubted sympathetic ganglia, as shown by the 

 investigations of Retzius, KoUiker and others, as well as the results of experimental • 

 studies (Apolant), justifies the conclusion that these ganglia are properly regarded 

 as belonging to the sympathetic group. They are, therefore, probably stations 

 in which certain motor and secretory fibres contributed by various ner\'es end in 

 arborizations around sympathetic neurones, from which axones pass for the immedi- 

 ate supply of involuntary muscle and glandular tissue. The fact that these small 

 ganglia are derivations of the early Gasserian ganglion is in accord with the mode 

 of origin of the sympathetic ganglia elsewhere (page 1013)- 



Fig. 105S. 



Internal carotid artery 

 IV. nerve 

 Cerebral peduncle 



Levator palpebrae superior!* 



Superior oblique muscle 

 — Lichrymal gland 



Superior rectus muscle 



I ong ciliary branches of nasal nerve 



Ext. rectus, insertion 

 Inferior oblique muscle 



Middle cerebellar 

 peduncle 



Gasserian gang^Hon 



Ext. rectus muscle 



\'I. nerve 

 Ganglionic branch of nasal 



Branch to inf. oblique 

 Stiort ciliary nerves Inferior rectus muscle 



Dissection of right orbit after removal of its lateral wall ; external and superior eye-muscles have been cut and 



displaced to expose ciliary ganglion and nerves. 



The Ciliary Ganglion. — The ciliary, ophthabnic or Icnticula? ganglion 

 (g. ciliare) (Fig. 1058), as it is varyingly called, is a small reddish mass, about 

 2 mm. long in the antero-posterior direction, and approximately quadrilateral in out- 

 line. It is compressed laterally and to each angle is attached one or more bundles of 

 nerve-fibres. It lies near the apex of the orbit on the outer side of the optic nerve, 

 between the latter and the external rectus muscle and anterior to the ophthalmic artery. 



The nerve-cells within the ganglion are chieliy multipolar elements, which 

 closely resemble sympathetic neurones (Retzius) and send their axones towards the 

 eye by way of the short ciliary nerves. 



Roots. — All of these enter the posterior margin of the ganglion. The motor 

 or short root (radix brevis), the thickest of the roots and sometimes double, is an off- 

 shoot from the branch of the oculomotor nerve which supplies the inferior oblique 

 muscle. It is short and comparatively robust and joins the postero-inferior portion 

 of the ganglion. The sensory or long root (radix longa) arises from the nasal branch 

 of the ophthalmic, leaving the latter between the heads of the external rectus. It is 

 long and slender and passes forward to enter the upper JDosterior angle of the gang- 

 lion, occasionally being fused with the sympathetic root. The sympathetic root (radix 



