CHAPTER III.

         THE COLUMNS OF THE SPINAL CORD.
Having given a general sketch of the regions of the model and structures in
shown how its principal structures are related to the central fibre traced into the
                                                the spinal cord
mass, each of the structures of the spinal cord may next be traced Medul1a'
into the medulla oblongata.  Starting with the central canal its en-
tire course is not shown in any one plate, but it can be traced as
follows:-In Plate v the canal is shown within the cord.  In en-
tering the medulla oblongata it curves dorsalward along the border
of the medulla sheet unt.il it opens out into the fourth ventricle as
seen in Plate III.  The relation of the aqmeductus cerebri to the
third ventricle can be traced in Plate II.
A view of the lateral surface of the model gives the best idea of
its relations to the spinal cord (Plate II).  The ventral funiculus is
not seen, but the lateral and dorsal funiculi are plain.
On the distal edge of the model (Pl,ate II) is a shallow groove
which divides the lateral funiculus into two parts. This groove cor-
responds to the line' on Text-Fig. 1.  The ventral portion is the
fasciculus ventrolateralis, which, as the model will show, is sub-
divided in the medulla. oblongata into four definite bundles and
certain scattered fibres. The dorsal part, or funiculus lateralis,
is divided into two parts, (1) the fasciculus cerebellospinalis, or
direct cerebellar tract, which occupies the lateral surface at the
distal end of the model, and (2) a mass of fibres concealed from the
surface which enters into the formation of the formatio reticularis
area of the medulla oblongata.  The fasciculus cerebellospinalis
lies near the surface and joins with a bundle belonging to the
system of the dorsal funiculi to make the corpus restiforme
(Plate' 11).
The dorsal funiculi of the spinal cord are shown in Plates II to VII
(omitting VI).
In entering the medulla oblongata the fasciculi gracilis and cu-
neatus (Go11 and Burdach) slant dorsalward and spread out into a
nuclear capsule (Plate llj.  This capsule is continuous with the
corpus restiforme.  The nuclei of the dorsal funiculi can be seen
in Plates IV and VII.


36    VENTEOLATERAL COLUMN OF THE SPIKAL CORD

The dorsal horn is visible in the surface view in the model, for
the fasciculus of Lissauer has been removed.  At the beginning of
the medulla oblongata, the dorsal horn, swollen into a large sub-
stantia gelatinosa, becomes continuous with the nucleus of the
tractus spinalis nervi trigemini (Plates II and IV).  A full discus-
sion of the gray matter of the cord in relation to the model is left
for Chapters v and VI.

A.-VEWMtOLATERAL FUNICULI.

ventz;g;I  (a) Pars Ventralis of the Ventrolateral B'uniculi.-The separate
   . funiculi of the spinal cord will now be considered in detail, begin-
   ning with the ventrolateral fasciculus.  This column includes all

Direct cerebellar tract

Fro. I.-Transverse section of the Spinal Cord at the level of the distal end of the
model.

     of the white matter below the transverse line in Text-Fig. 1, for
     the pyramidal tracts are no,t yet medullated.  It will be clear that
     the ventrolateral column as seen in Text-Fig. I, is a cross-section
     of the trough at the distal end of the model (Plates v and VII).  As
     has been said, the walls of the trough are divided in the medulla
     into four definite bundles, and certain scattered fibres.
Fibres to poatefior  The first group includes the most medial and ventral fibres
long%% (Plates v and VI).  They have already been described as turning
     dorsalward along the border of the medulla sheet to make the
     fasciculus longitudinalis medialis.

In the transverse sections they are visible in Figs. 27 and 2S, (F. v. 1.
OF F. v. p.), both of which give a cross-section of the trough where it
is opening out onto the medulla sheet.  Fig. 20 shows these fibres in
longitudinal sections. The trough is lettered F. 1.


VENTROLATEXAL COLUMK OF THE SPINAL CORD     37

The second bundle leaves the lateral funiculus a little farther Fibres to medial
cerebralward (Plate v, Fasciculus lateralis [a]). It passes obliquely lemni*cus'
toward the midline and is represented in the model as stopping
abruptly against the root of the N. hypoglossus.  In reality the
fibres pass on between the root bundles of the nerve adjacent to t,he
medial lemniscus (Fig. 19, F. 1.). In so,me of the sections it is
possible to trace the fibres of this bundle through the parts of the
medial accessory olive into the lemniscus medialis.  Other fibres
pass out into the proximal lobe of the nucleus olivaris inferior, the
wall of which they do not appear to penetrate.

The shape of this second bundle in the model is peculiar, for the
dorsal fibres do not appear to come from the lateral funiculus at all.
They represent a little group of fibres which come from the forma-
tio reticularis and pass with the bundle in question toward the area
of the medial lemniscus.  As the bundle is crossing from the lateral
funiculus toward the middle line a small group of fibres becomes
separated from the mesial surface of the main mass, passes parallel
to it for a short distance and then joins with it again.  It cannot be
seen in the lateral views given in the plates, but it shows in Figs.
19 and 28.  It is not. labeled in either section but is a small bundle
of fibres within the trough.  (In Fig. 19 the line F. a. i. passes
through it.)  Its meaning I do not know.  To return to the main
bundle, the model shows the following points: (1) The bundle is
connected with the lateral funiculus of the cord; (2) it does not
decussate in the medulla oblongata; (3) it runs parallel to the
medial lemniscus at the level of the inferior olive; (4) its fibres
appear to join the lemniscus in part and in part to turn toward the
olive, beyond which they cannot be traced in these preparations.
If this bundle joins the lemniscus medialis it may represent, a sen-
sory path from the lateral funiculi which does not decussate in the
medulla oblongata.

The t,svo bundles just described receive the medial and ventral
fibres of the fasciculus ventrolateralis (Text-Fig. 1).  The lateral
fibres pass onward to a point opposite the distal end of the inferior
olive, where the bundle divides into tivo parts (Plates IV and v). Fibresfrom

Deiter's nucleus

This statement is made without regard to the direction of the to the spinal cord.
axones of the fibrea.  The larger and medial of these two bundles
extends between the lateral funiculus of the cord and the lemniscus
lateralis (Plates IV and v).  It does not join the lemniscus, but


38    VENTROLATERAL COLUMN OF THE SPINAL CORD

rather passes beyond the point of meeting; its fibres, however,
could not be traced farther in the longitudinal series.  The lateral
lemniscus leaves the trapezo,id body just dorsal to the nucleus
olivaris superior which lies embedded within the trapezoid body.
The bundle connected with the cord touches the lemniscus lateralis
just dorsal to the medial border of the superior olive.  The two
bundles make a slight angle in which lies the nucleus of the facial
nerve. The bundle will be traced spinalward inasmuch as this
is the direction taken by at least a port,ion of the axones of its
constituent fibres.  Starting from the point where it touches the
lemniscus, it passes at once ventralward, lateralward and spinal-
ward.  The bundle spreads out in its course and sweeps around the
surface of the inferior olive to join the lateral funiculus of the
cord (Plates IT and v).

This bundle must be studied carefully in both series of sections. In
the longitudinal series, a considerable portion of the bundle can be seen
in one section (Fig. 13, Tr. fr. Nu. D.).  Its approach to the fasciculus
lateralis of the spinal cord can be seen in Fig. 16.  I wish to emphasize
two points shown in Fig. 13: (1) that though the bundle adjoins the
lateral lemniscus, its fibres are cut at a different angle, that is, more
obliquely (compare Plate v), (2) that the bundle can be recognized
from its relation to the nucleus of the facial nerve.
Turning to the transverse series the bundle is determined readily by
this relation.  In Fig. 38 the bundle corresponds with the tract described
as passing from Deiters' nucleus to the spinal cord. It can be seen in
Figs. 36 to 38, in which its fibres are passing dorsalward through the
formatio reticularis.  These sections include the area between the pars
prima and pars secunda of the N. facialis (Plate v); hence the bundle
scatters in its dorsal course so that it is not strange to lose it in the
longitudinal sections, in which its fibres must be cut across. Even in
the transverse series I cannot demonstrate the connection of the bundle
with Deiters' nucleus.'

Undetebmm~ed  The last and smallest of the four bundles from the ventral part
   * of the lateral funiculus maintains a lateral position throughout its
        course.  It passes along the surface through the entire length of
    the medulla oblongata and joins the trapezoid body midway be-
    tween its dorsal and ventral aspects (Plate v).  In the trapezoid
    body it is wholly lost from view.

The bundle is horizontal, so its complete course can be seen in one
section (Fig. 17).  It can be followed as readily in the transverse series

1 The position of the bundle corresponds with RamBn y Cajal's descrip-
tion.  Ram& y Cajal, 5. Beitrag zur Studium der Medulla oblongata, des
Eleinhirns und des Ursprung der Gehirnnerven. Deutsche Uebersetz.
von Bresler, Leipzig (1896), S. 71.


DIRECT CEREBELLAE TRACT OF THE SPINAL CORD    39

(Figs. 30 to 35) (F. 1.).  This bundle is labeled the fasciculus anterior by
Edinger?

It may correspond to v. Bechterew's 2 aberrant bundle. As regards
Gowers' tract the section in Taf. IX of Hoche's article: shows the fibres
of Gowers' tract just ventral to the tractus spinalis N. trigemini.  The
section is taken opposite the middle of the inferior olive proximal to the
passage of the fasciculus cerebellospinalis into the corpus restiforme.
In the series I have studied, a corresponding section has this area as a
non-medullated space, while ventral to it lies the bundle shown in the
model. A second section in my series, taken to correspond with Fig. `7,
Taf. IX of Hoche's paper, will show still more clearly the non-medulla-
tion of the fibres of Gowers' bundle as described by Hoche (Fig. 38).
At this level Gowers' tract cuts across the pars secunda of the facial
nerve, just as it plunges into the corpus trapezoideum and this area in
my series is non-medullated. At the level of Fig. 38, the fourth bundle
of the model is no longer visible.

These four bundles in the medulla oblongata. contain all of the
fibres of the fasciculus ventrolateralis, medullated at this stage,
with the exception of certain fibres of the formatio reticularis.
These come from the mesial part of the lateral wall of the trough
(Plate VII).  They spread out in the medulla oblongata and consti-
tute the ventral bundle of the formatio reticularis.'  This bundle is
much smaller than the dorsal bundle of the formatio reticula&

(b) Pars Dorsalis of the Funiculus Lateral&.-Turning now to Do& 6im of
the dorsal part of the lateral funiculus of the cord, the section lateral "iumn.
in Text-Fig. 1, shows that it contains two fibre masses; one lateral,
the fasciculus cerebellospinalis, or direct cerebellar tract, and one
more medial, a part of the fasciculus lateralis proprius (Flechsigi),
or the so-called lateral ground bundle.

At the distal edge, of the model the direct cerebellar tract forms pz;;t cerebellar
a band or ribbon on the surface of the spinal cord (Plate II and Text-    *
Fig. 1). In approaching the medulla oblongata the fibres con-
verge to form a compact bundle (Fig. 28). In this bundle the fibres

* Edinger, L., Vorlesungen iiber den Bau der nerviisen Centralorgane,
Leipzig (1893), S. 186.
2 Barker, L. F., op. cit.
x Hoche, A., Ueber secundlre Degeneration, specie11 des Gowers' . . .
schen Biindels, nebst Bemerkungen iiber das Verhalten der Reflexe bei
Compression des Riickenmarkes.  Arch. f. Psychiat. u. Nervenkr., Berl.,
Bd. XXVIII (X396), S. 510-543.

4 This is a part of the vordere gemisclhte b'eitenstrangxone of Flechsig.
Flechsig, P., Die Leitungsbahnen im Gehirn und Riickenmark, Leipzig
(1876), s. 305.


40    LATERAL GROUND BUNDLE OF THE SPINAL COED

    pass on to a point opposite the distal end of the inferior olivary
    nucleus where the entire bundle turns dorsalward at almost a right
    angle' (Plates II and v with Fig. 30).  The lines in Plate II of the
    model showing this dorsal course are perhaps a little' too abrupt.
    They should follow the course of the lines of t,he transverse sec-
    tions shown on Fig. 52.  The fibres extend dorsalward beyond the
    level of the tractus spinalis nervi trigemini; here they turn cere-
    bralward again and join with the dorsal external arcuate fibres to
    enter the corpus restiforme.  This arcuate bundle shows in the
    model as the direct continuation of the capsule of the nuclei of the
    dorsal funiculi (Plate II).  The line in which the direct cerebellar
    tract meets this arcuate bundle forms an arch, beneath which the
    tractus spinalis nervi trigemini and its nucleus can be seen.  The
    corpus restiforme passes cerebralward, and at the same time
    slightly lateralward, to a point opposite the level of the nucleus
     N. abducentis.  Here it turns dorsalward to enter the cerebellum
     and hence is cut off in the model.
Lateralb~$y~d  To return to the cross-section of the spinal cord shown in Text-
   ' Fig. 1, all of the medullated fibres of the lateral funiculus have
    been traced save the ground bundle, for at t.his stage the lateral
    pyramidal tract is non-medullated. The model shows that the
    ground bundle of the lateral funiculus has only to turn slightly
    dorsalward, in agreement with the cervical curve in order to enter
    the formatio reticularis of the medulla oblongata.  (See the cross-
    section of the cord in Plate v.)  This formatio reticularis region
    extends throughout the length of the medulla.  It lies dorsal to the
     nucleus olivaris inferior and lateral to the medulla sheet.

B.-FUNICULUS DORSALIS.

Dorsal columns.  The dorsal funiculi of the spinal cord form a wedge-shaped mass
    as seen in the cross-section (Text-Fig. 1). Each funiculus runs
    to the beginning of the medulla oblongata without change of form
    save that the groove between the fasciculus gracilis (Goll) and the
    fasciculus cuneatus (Burdach) deepens (Plates II and III). At
    about the junction of the spinal cord and medulla oblongat,a, the
    fasciculus gracilis becomes hollowed out to make a capsule for
     its nucleus and a little farther cerebralward the fasciculus cuneatus
    shows the same change.  This capsule can be best understood after
      the nucleus has been described.


DO~AL COLUMES OF THE SPINAL CORD       41

The nucleus of the dorsal funiculus of the cord is seen best after Nuclei of the
removing the fibre capsule (Plates IV and VII). It is an irregular doFsa1 columns.
mass of cells, which is divisible into three parts; moreover, this divis-
ion, made from form alone is strengthened by the mode of dis-
tribution of the fibres.  In general the distal portion of the nucleus
has a long diameter in a dorsoventral plane (Plate VII) at right
angles with the long axis of the proximal portion (Plate IV).  The
three divisions, as seen from a lateral view, are (1) a distal, (2) a
middle and (3) a proximal part.  The middle portion does n'ot ex-
tend to the mesial surface of the nuclear mass and so may well be
called the lateral. portion.  (Kucleus funiculi cuneati lateralis,
Plate' IV.)

The distal part or nucleus funiculi gracilis consists of a column
of cells placed in a dorsoventral direct,ion.  Its distal margin is
straight but the dorsal margin is curved and raised above the rest
of the nuclear mass (Plate IV).  It is separated from the middle
nucleus by a deep groove but its surface is smooth, thereby contrast-
ing with the proximal portion.  The rest of the mass has been
called the nucleus funiculi cuneati, but Blumenau has shown that
it consists of two distinct parts.  The middle part, or nucleus of
Blumenau is a mass of cells projecting from the lateral surface
(P1at.e IV. Nucleus funiculi cuneati lateralis). It. is separated from
the distal nucleus by a deep groove but fades gradually into the
proximal nucleus.  Its distal border is about opposite the middle
of the nucleus funiculi gracilis, while its proximal limit is opposite
the lower part of the nucleus olivaris inferior, and the distal end of
the radix descendens nervi vestibuli.

In the model, the nucleus cannot be traced as far cerebralward
as Blumenau was able to trace. it from histological details.  Blum-
enau 1 places the proximal limit opposite the lowest plane of en-
trance of the fibres of the N. acusticus.  The sections of both my
deries show small, scattered masses of cells in the corpus restiforme,
and these can be traced even into the cerebellum itself.  They are
considered by Blumenau to be part of the nucleus which bears his
name.  As has been said, the nucleus of Blumenau does not reach
the me&al surface of the nuclear mass.  The thin mesial zone con-

`Blumenau, L., Ueber den Zusseren Kern des Keilstranges im verlh-
gerten Mark. Neurol. Cent,ralbl., Leipz., Bd. x (1891), S. 229.


42            SENSORY DECU~SATIOX

sists (1) of a small column of cells projecting parallel to the nucleus
funiculi gracilis, and (2) a layer of cells associated with the prox-
imal nucleus.  This mill be explained in connection with the course
of the fibres from these cells.

     The proximal portion of t,he mass is oblong in shape.  It is char-
    acterized by the irregularity of its lateral surface which is broken
    by fibre bundles.  One deep depression is to be seen near its ventral
      surface.

Internal arcuate
   flbres and  Further evidence of the division of this nucleus into three parts
  decussatio is seen in the course of the fibres from it.
lemniscorum.                         In Plate VII it will be
    noted that, while both the distal and proximal divisions give bun-
    dles of fibres that run toward the raphe, no such bundle comes
      from the lateral nucleus.  These two bundles of internal arcuate
    fibres, distal and proximal, are wholly distinct from one another
    in the longitudinal series.  In the transverse series, on the other
     hand, it can be made out that the thin medial border of the middle
    zone makes a transition between the distal and proximal bundles.

The distal bundle leads to the decussatio lemniscorum.  It is a
small, compact bundle, which comes (1) fromm the distal third of the
nuclear mass, the nucleus funiculi gracilis, and (2) from the distal
part of the thin middle zone of the mass, the nucleus funiculi cune-
ati.  The bundle leaves the proximal border of the nucleus funi-
culus gracilis and hence appears in transverse section to arise wholly
from the nucleus funiculi cuneati (Fig. 2s).  It is found in the
distal part of the medulla oblongata, distal to the olive and oppo-
site the proximal end of the decussatio pyramidum.'  The bundle
passes along th,e border of the central gray matter, to a point ven-
tral to the central canal, where it decussates in mass between the
medulla sheets of the two sides and joins the stratum interolivare
lemnisci (Plate VII).

The proximal bundle of internal arcuate fibres, on the other
hand, is different both in position and in form.  It is related to the
proximal part of the nuclear mass and forms a broad band which
appears as a direct continuation of the entire proximal third of the
nucleus into a fibre bundle (Plates IV and VII). This bundle
smceps across the medulla in a curve, dorsal to the olive, pierces t'he
medulla sheet, turns ventralward to decussate in the raphe, and

`Ramh y Cajal, op. cit., S. 52.


~CTJATE FIBRES               43

joins the stratum interolivare lemnisci of the opposite side.  This
bundle contrasta with the distal arcuate bundle: (1) in position, for
it lies opposite the middle of the nucleus olivaris inferior, while the
latter is distal to it; (2) in course, for its fibres arise far lateralward
and pass through the formatio reticularis instead of bordering upon
the eentrai canal; and (3) in the arrangement of its fibres into a
broad band instead of a compact bundle (Figs. 28 and 31, F. a. i.).
According to v. Bechterew 1 the fibres from the fasciculi of Go11
and Burdach can be distinguished from each other throughout the
pans.  The mesial border of the middle zone gives off a few fine
arcuate fibres which make a transition between the distal and prox-
imal bundles. At first they lie near the central gray matter after
the type of the distal bundle, but they gradually pass farther to the
side until the proximal bundie is reached.

The model shows that the lateral nucleus of Blumenau ' is in the
axact position to send its fibres lateralward to the cerebellum rather
than medialward to the medial lemniscus on its way to the cerebrum.
This will appear clear by comparing Plates II, III and IV.
The capsule of the nuclei of the dorsal funiculi of the cord is
continued directly into the corpus restiforme.  This connection is
made by means of dorsal external arcuate fibres.  These arcuatea
come from two sources, (1) from the dorsal funiculi of the cord,
(2) from the nucleus of Blumenau."

' v. Bechterew, W., Ueber die Schleifenschicht auf Grund der Resultate
von nach der entwickelungsgeschichtlichen Methode ausgefiihrten
Untersuchungen. Arch. f. Anat. u. Phys., Anat. Abth., Leipz. (1895),
s. 379-395.
*Blumenau, op. cit., S. 226.
`In regard to the literature on this subject, Edinger, Flechsig, Hoche
and v. Monakow say that fibres of the dorsal funiculi pass directly to
the corpus restiforme. Vejas on the ground of experimental degenera-
tion says that the dorsal funiculi and the corpus restiforme are con-
nected only by mediation of a nucleus.
(1). von Monakow, C., Arch. f. Psychiat. u. Nervenkr., Berl., Bd. XIV
(1883).
(2). Edinger, L., Neurol. Centralbl., Leipz., Bd. III (1885), S. 73-76.
(3). Flechsig, P., Neural. Centralbl., Leipz. (1885), No. 5.
(4). Vejas, P., Arch. f. Psychiat. u. Nervenkr., Berl., Bd. XVI (1885),
S. 200-214.

(5). Barker, L. F., Op. cit., p. 560 and p. 575.
Flechsig calls these fibres, " Fibrae transversales." Die Leitungsbah-
nen im Gehirn und Riickenmark des Menschen, Leipzig, 1876.


44      DORSAL COLUMNS OF THE SPINAL CORD

Dorsal columns
of cord and their
nuclei in sections.

The transverse series will be used fjrst to illustrate the points of the
model (Figs. 25 to 31). Fig. 25 shows that the nucleus funiculi gracilis
is well developed at a level in which only the ventral part of the nucleus
funiculi cuneati is visible.  Fig. 28 shows both the nuclei of the fasciculi
of Go11 and Burdach, together with the nuclear capsules and the distal
bundle of internal arcuate fibres.  The capsule of the nuclei of Bur-
dach's fasciculus is dense, while that of the nucleus of Gall's fasciculus
is delicate. The characteristics of the distal internal arcuate bundle
are evident in Fig. 28.  The proximal bundle on the other hand is shown
in Fig. 31, while the transition between the two is represented by Fig.
29. Figs. 29 and 30 show the lateral nucleus of Blumenau (Nu. f. c. 1.).
In the second section its close connection with the fibre capsule and
the contrast of its cellular arrangement with that of the proximal
nucleus is evident.

The relative positions of the three parts of the nuclear mass are more
clearly made out in the longitudinal series (Figs. 5 to 1'7).  The sections
in Figs. 5 to 7 illustrate these relations.  The nucleus funiculi gracilis
and a small part of the nucleus funiculi cuneati form a common mass
that gives rise to the distal internal arcuate bundle. The middle, lat-
eral portion is the nucleus of Blumenau (Nu. f. c. l., Fig. 5). At the
level of Fig. 7 it is separated from the proximal third by a band of
fibres entering the nucleus from the capsule. All three sections pass
through the corpus restiforme.  The fibre bundle opposite the nucleus
of Elumenau is much broken, due to the entrance and exit of the fibres
of the capsule.
In passing ventralward the internal arcuate fibres can be traced to
their decussations. On Fig. 9 the proximal third of the nucleus seems
to have been transformed into fibres. These fibres can be traced
through Figs. 12, 13 and 15.  The distal bundle which lies farther ventral
is seen first on Fig. 15 and is traced to the decussatio lemniscorum in
Figs. 17 and 19.