SPINAL CORD. 423 
time it must be noted that these two median clefts present many points of differ- 
ence. The antero-median fissure (fissura mediana anterior) is for the greater part of 
its length much shallower than the postero-median fissure. 
In the cervical and dorsal regions it only penetrates for a 
distance corresponding to somewhat less than a third of the 
antero-posterior diameter of the cord. Further, the antero- 
median cleft is much the wider and more apparent of the 
two, and the pia mater dips down into it and forms a fold or —CV1 
reduplication within it. The postero-median fissure (fissura 5.31004 median 
mediana posterior) in the cervical and dorsal regions pene- fissure 
trates into the cord until it reaches a point somewhat 
beyond its centre. It is extremely narrow, and contains Cervical swelling_| 
a single septum which is derived from ependymal and __ Posterior para-_| 
median fissure 
neuroglial elements, and is intimately connected with the at ee ne 
adjacent sides of the two halves of the cord, between fissure 
which it intervenes. The pia mater, which invests the 
surface of the cord, passes continuously over the postero- 
median fissure and sends no prolongation of any kind into 
it. In the lumbar region of the cord the postero-median 
fissure becomes shallower, whilst the antero-median fissure 
deepens, and ultimately in the lower part of the cord the 
two fissures present a very nearly equal depth. 
The two halves of the cord, which are marked off from 
each other by the median fissures, may show trifling differ- 
ences in the arrangement of the parts which compose them ; 
but to all intents and purposes they are symmetrical. They 
are joined together by a more or less broad band or com- 
missure, which intervenes between the two median fissures. 
An inspection of the surface of each lateral half of the 
cord brings into view a longitudinal groove or furrow, at 
some little distance from the postero-median cleft, which 
extends along the whole length of the cord. Along the 
bottom of this groove the fascicles of the posterior nerve- 
roots enter the cord in accurate linear order. It. is called 
the postero-lateral sulcus (sulcus lateralis posterior). There 
is no corresponding furrow on the forepart of each lateral 
half of the cord in connexion with the emergence of the 
fascicles of the anterior nerve-roots. These fascicles emerge 
irregularly over a broad strip of the surface of the cord, 
which corresponds in its width to the thickness of the 
subjacent extremity of the anterior horn of gray matter. 
The postero-lateral groove subdivides each lateral half of 
the cord into a small posterior column (funiculus posterior) 
and a much larger antero-lateral column, and it is customary 
to arbitrarily map off the latter into a lateral column (funi- 
culus lateralis) and an anterior column (funiculus anterior) 
by a line corresponding to the emergence of the outermost 
fascicles of the anterior nerve-roots. 
In the cervical region a distinct longitudinal groove may 
be observed on the surface of the posterior column. It is Fic. 318.—Drtacram or THE 
placed rather nearer to the postero-median than to the pase SO ast SERN 
postero-lateral furrow, and as it is traced down into the 
: : ; a ote r CVr shows the level of the 1st 
dorsal region it gradually becomes indistinct and finally dis- cervical vertebra; CVv of the 
Cot " ° ° & 5th cervical vertebra ; DVir of 
appears. This is called the posterior paramedian groove, and the 2nd dorsal vertebra; DVX 
1 alea wy qa e of the 10th dorsal vertebra ; 
it marks on the surface the position of a septum of Diet Pinyin of the winiderasl ver: 
mater which dips into the cord and subdivides the posterior — tebra; Lv of the 2nd lumbar 
‘ fs vertebra. 
column into an outer part, termed the funiculus cuneatus 
or the column of Burdach, and an inner portion, which receives the name of the 
funiculus gracilis or the column of Goll, 
Tae AA 
DVx 
Lumbar swelling_ 
he 
