384 Renumeration of the Spinal Nerves, ete. [ April, 
4. Another good effect of the renumeration is, that the great 
nerve called fifth lumbar, issuing between the last lumbar and 
first sacral vertebræ, and so remarkably distinguished from the 
rest in size and disposition that is already known as the “ lum- 
bo-sacral cord,” is taken out of the lumbar series altogether and 
put where it belongs, in the sacral series, as first sacral. The 
sacral plexus is commonly said to be formed by the lumbo-sacral 
cord (5th lumbar) and the four upper sacral nerves (tst-4th) 
which issue from the completed anterior sacral foramina, or by 
these and the next nerve below. I should say simply that the 
sacral plexus is formed by the five (1st-5th) sacral nerves proper 
There is of course the loop of communication with the lumbar, 
as above said, and there is also connection with the coccygeal 
nerve or nerves ; but these are not to be taken into account in 
defining the plexus. The natural division of this very large but 
comparatively simple plexus is not into a lumbo-sacral cord (Ist 
sacral) and four (2d—sth) sacral nerves, but into the four as 
upper nerves (1st-4th sacral proper) and the much smaller (5t) 
sacral one. 
5. The remaining very diminutive nerves are connected re , 
the preceding. There being no inter-coccygeal foramina, | 
are obliged to appear together between the sacrum and coccy® | 
Nor are they constant in appearing. It is scarcely ma! 
whether we consider them merely tributary to the eee 
plexus, or together forming a little coccygeal plex a : 
it is customary to take them into the sacral plexus, 1 
this great plexus is made up of four large coras ae e point Ë 
ones, and a single coccygeal is left alone. The chief and 
here, that any nerve or nerves issuing between the wer and 
coccyx must be coccygeal, whether there be one or WoT . 
whatever disposition be made of it or them. spoke 
To strip the subject of verbiage as far as possible, : ee yndet 4 
of the plexuses as formed by the nerves. It is of COUN ae 
stood that I mean their anterior branches in every i 
Se NO ES er Ny ee ee ee 
are 
communications between posterior branches of spina’ the 
not generally treated as plexuses, unless it be those aie ad 
1st-3d cervicals, which some writers formally recogni “ crasil 
name. The same may be said of connections Nora ay É 
and spinal nerves, as that of the hypoglossal ~~ ate 
the sympathetic plexuses here brought into qu 
estion. 
