ON THE ANATOMICAL RELATIONS OF THE NUCliEI OF RECEPTION OF THE COCHLEAR   &`*
              AND VESTIBULAR NERVES.

                       BY FLORENCE R. SABIN.

[From t116 Anatomical Laborat& of t?u Jdhns Bopkd Uniwra'ty.]

Since the investigations of Babinski,' v. Bechterew,9 Bumm,'
Cramer,' Flechsig," Fore],' Kirilzew,' v. Monakow," Onufro-
wicz," and Roller," much light has been thrown on the
central connections of the cochlear and vestibular nerves by
Ram& y Cajal,' Held," v. KGlliker," Martin" and Sala.`"
The exact topographical relations of these nuclei have, how-
ever, so far been only imperfectly described.
The material used in the present study was human tissue
and consisted of two superb sets of serial sections, transverse
and horizontal, through the medulla of the new-born babe,
prepared by Dr. John Hewetson at the Anatomical Laboratory
of the University of Leipzig.  Through the courtesy of Dr.
Hewetson these preparations have been made accessible for
study to research-workers in the Anatomical Laboratory of
the Johns Hopkins University.

A flat reconstruction on mil!imetre paper has been made
from the right-hand side of the sections of the transverse
series which show the nuclei in question. Reference to the
diagram (Fig. 1) will show the following points : At the lower
end of the diagram the zero point on the scale represents the
superior (anterior) limit of the decnssation of the pyramids, and
at the upper end the diagram extends nearly to the lower
border of the inferior colliculua of the corpora quadrigemina
The lines drawn across the diagram represent approximately
the planes of the sections having the corresponding numbers.*
The areas. occupied by the nuclei of the nervus hypoglossns
and nervus abducens are given to help in orientation. The
lines a-a represent the lateral boundary of the fourth ventricle,
which has been traced from the point at which the canalis
centralis opens out into the floor of the ventricle, through the
area of the recessus lateralis and forwards to the aqueductus
oerebri.  The line 6-b represents the lateral boundary of the
corpus restiforme.  The entrance of the corpus restiforme into
the cerebellum is not shown, but the line runs to its upper

*The planes of the sections are in reality slightly different from
those represented by the lines on the diagram, which are drawn at
right angles to the median line. The sections have been cut
slightly obliquely, the right side being struck at a higher plane
than the left.  The slight discrepancies between the drawings of the
sections and the diagrams are thus explaiced.

limit.  The motor and sensory nuclei of the nervus trigeminus
are shown with the exception of the nuclei minores (radicis
descendentis). The tractus spinalis nervi trigemini, together
with the adjacent substantia gelatinosa, is represented in out-
line from its beginning, at the entry zone of the nerve, down-
ward as far as the decussation of the pyramids.  Its course
further spinalwards is not given.  The entering root bundle
of the nervns trigeminus is also not illustrated, but the lowest
section which shows it corresponds to number 45 on the scale,
and as the nuclei of the nerve are inferior to the point where
it enters, the fibres can be traced farther upwards than the
diagram goes. The lines da and dr represent the surface
markings on the floor of the fonrth ventricle corresponding to
the ala oinere& The complete length of the nucleus alre
cinereae is not shown, but it can be traced from the inferior
end of the nucleus nervi hypoglossi to the point marked dl
on the diagram.  The line d,-ds, in which the two snlci meet,
corresponds to the portion of the ala cinerea which has been
pushed into the depth by the spreading of the nucleus nervi
vestibularis medialis dorsal to it over the floor of the ventricle.

The line B represents the continuation of the lateral snlcns
over the area occupied by the nucleus nervi abducentis.  The
sulcus is here further lateral, corresponding to the position of
the nucleus nervi abducentis, which is further from the
median line than the nucleus nervi hypoglossi.
N'w vsstibzcli.  The area of entrauce of the root bundle
of the vestibular nerve is shown in the diagram.  The well
known fact that the vestibular root bundle is farther forwards
(cerebralwards) than the cochlear root bundle is well illns-
trated.  The reconstruction shows clearly the generally
recognized fact that the four principal vestibular nuclei are
continuous with one another.  (See X, L., 8., and R. d. IZ. ve.
in the diagram.)  These nuclei can be distinguished in part
by position and in part by the character of the cells within
them.  The relation of the nucleus nervi vestibnlaris medialis
tc the nucleus of the descending tract of the vestibular nerve
is very striking.  Ram6n y Cajal has already pointed out their
close connection.  The lowest sections in which descending
vestibnlar fibres can be distinctly made out show cells
between the fibres (sections between 15 and 17 on the
scale).  These cells higher up make an oval mass which lies


JOHNS' BOPKINS BOSPITAL BULLETIN.

lateral to the ala cinerea and extends dorsal- and medial to the
descending vestibular fibres.  As the ala cinema recedes into
the depth, and the nucleus nervi hypoglossi disappears, these
cells spread to very near the middle line.  The large area N,
together with the dark area Y, represents the nucleus nervi
vestibularis medialis; it can easily be seen that any division
between this nucleus and the nucleus of the descending vesti-
bular tract, throughout their whole extent, must be merely an
arbitrary one. It is extremely di5cult, too, to determine
exactly the medial border of the nucleus nervi vestibuli
medialis ; it goes over insensibly into the central gray matter
surrounding the ventricle.  In general the nucleus nervi
vestibularis medialis begins from 2& to 3 mm. below the
superior end of the nucleus nervi hypoglossi and extends in
the floor of the fourth ventricle as far forward as the nucleus
nervi abducentis. Its anterior extremity (Yin the diagram)
passes forward some distance further lateral to the nucleus of
the sixth nerve. *The descending tract of the nervus vesti-
buli begins at the entry zone of the vestibular root fibres in
the regiou of the nucleus nervi vestibularis superior (Bech-
terew), and of the nucleus nervi vestibularis lateralis (Deiters).
It is made up of the descending branches of the root fibres
and lies dorsal to the tractus spinalis nervi trigemini, at first
at a distance. of 1.3 mm. from the floor of the ventricle
(Fig. 3).  Farther posterior it approaches the floor, and the
isolated bundles of fibres of which it is made up occupy a very
characteristic oval area, the long diameter of which lies in the
dorso-ventral direction (Fig. 2).  A reference to the diagram
will show that it extends downward from its origin in a
straight line as far as the level of the superior (anterior) end
of the nucleus nervi hypoglossi.  From this point it curvea
medialwards, giving place to the nucleus funiculi cuneati.  It
can be traced downwards to a plane a little superior to the
middle of the nucleus nervi hypoglossi.  The ascending
branches of the vestibular fibres are not represented in the
diagram, but they are shown in figs. 3 and 4.*

At the extreme superior and lateral angle of the nucleus
nervi vestibularis medialis is situated a large group of cells, in
part capping the descending tract of the vestibular nerve
(Fig. 3, NT.L y).  It is oval in shape and is distinctly visible in
section just below the floor of the fourth ventricle,  As will
be seen in the diagram (Fig. 1, Y), it lies adjaoent to the
nucleus nervi vestibularis lateralis, to the nucleus nervi vesti-
bularis medialis, aud to the nucleus nervi vestibularis spinalis
(Radix descendens). This nucleus, however, is worthy of a
special description in that it is peculiar: (1) in the size of
the cells, they being much larger than those of that part of
the nucleus nervi vestibularis medialis marked M in the
diagram, but smaller than' those of the nucleus nervi. vesti-
bularis lateralis; (2) by the staining capacity of the mass,
which on the whole stains in Weigert-Pal preparations of the
new-born babe much darker than Deiters' nucleus of the

*The so-called cerebellar acoustic nucleus of Ram& y Cajal, the
cells of which accompany these fibres, is not represented. ho
attempt WSB made to locate in the diagram the gray masses in the
roof of the cerebellum, with which the ascending branches of the
vestibular nerve undoubtedly come into relation.

same section ; (3) by the fact that the cells are closely packed
together, which brings it into marked contrast with the more
scattered cells of the nucleus nervi vestibularis lateralis ; (4)
by its distinct outline in ~~11 stnined preparations, which
makes this group of cells easier to differentiate than any of
the other vestibular nuclei.  A refereuce to Figs. 3 and 4, and
to the diagram, Fig. 1, will show the position of the nucleus.
This nucleus evidently corresponds to a part of the gaflglicn
domate p+,ici of v. Kblli ker (Haupti$ern of Sch walbe.)  It is
continuous posteriorly with the nucleus of the descending
root, and laterally (in its posterior part) with the rest of the
nucleus nervi vestibuli medialis.  It is not so easy to lecate it
definitely in series in which the gray masses are not particu-
larly well differentiated, but even in such a series, after having
defined it easily in Dr. Hewetson's seotions,`its limits have
been recognized <without much difficulty; Until attention
can be paid to the course of the axones of these cells and a
comparison can be iustituted between its constituent neurones
and those of the other vestibular nuclei, I prefer to give the
group a distinct place in the diagram and to refer to it as
nucleus y.

It may further be seen in the diagram that the nucleus
nervi vestibularis lateralis and the nucleus nervi vestibularis
superior are in the region of the entry zone of the vestibular
nerve.  The lateral nucleus appears to be separated into two
portions by the root fibres of the nerve. One part (Zt in
Fig. 1, and A%. n. v. 2, in Fig. 3) is further inferior (posterior)
and-lateral, and it lies also further ventral than the other part
(Z in Fig. 1, and Nu. 12. v. I in Fig. 4).  Z1 lies between the
entry zone of the vestibalar root fibres and the corpus resti-
forme. Its cells are rather smaller than those of Z. The
part of Deiters' nucleus marked L lies in its npper part
almost in the floor of the fourth ventricle and is continuous
laterally with Bechterew's nuclens, from which it can be
easily distinguished, however, by the size of the cells.  In the
longitudinal series these two parts of Deiters' nuclei L and ZI
are seen to be in reality continuous ; a few scattered cells
joining them can be seen between the fibres of *the nerve.
They are seen with the high power not to be such separate
entities as the diagram would make them appear. In his
articles on the medulla oblongata Ramon y Cajal describes the
nucleus nervi vestibularis lateralis in the white mouse as a
crescent-shaped mass, convex on its dorsal border, and show-
ing two sorts of cells, the larger being further ventral, the
smaller more dorsal and lateral.  In human tissue I find that
the nucleus. is convex on the yentral border, and to be so
inclined that on the whole the smaller cells are further
ventral as well as lateral. Fig. 3 shows the lateral portion
(~511 of the nucleus nervi vestibularis lateralis, while Fig. 4,
which represents a section .6 mm. further forward, shows the
medial portion (I;).

The nucleus nervi vestibularis superior (Bechterew) lies in
the floor and lateral wall of the fourth ventricle, OccuPYing
its lateral angle. In the diagram, Fig. 1, it is marked 8 and
is given a heavy outline. It lies in a plane dorsal to that of
the nucleus nervi vestibularis medialis, and its inferior
(posterior) extremity corresponds about to the inferior
(posterior) end of Deiters' nucleus.  As seen in the diagram


DECEMBER, 1897.1

JOHNS HOPKINS HOSPIT AL BULLETIN.

255

it extends even further laterally than does the nucleus nervi
vestibularis lateralis of Deiters. A reference to Figs. 3 and 4
will show that it is bounded laterally in a part of its course by
the corpus restiforme. ,Ae the nucleus extends upwards (cere-
bralwards) it lies more and more dorsally, ao that it comes to lie
between the lateral wall of the ventricle and the brachium
conjunctivum. It is interesting to note how far it can be
traced at its cephalic extremity into the region of the nuclei
of the nervus trigeminus. It is travereed by the ascending
branches of the root fibres of the vestibular nerve.
There seem8 to be a general agreement that the root fibres
of the vestibular nerve bifurcate.  The descending limbs pass
into the descending root, many of the ascending go up i&o
the cerebellum. Recent investigations make it probable that
axones also run in the opposite direction from the cerebellum
to the nucleus nervi vestibularis lateralis.  Fig. 4 show8 two
distinct set8 of fibres extending between the cerebellum and
Deiters' nucleus; one running between the brachium con-
junctivum and the corpus restiforme and lying in the plane
of the transverse section for a considerable distance, the other
being more medial and going actually through the nucleus
nervi vestibularis superior and the brachium conjunctivum.
The latter fibres are so inclined that they do not run far in
the plane of any one section, but by following the series
downward (caudalwards) from the region of Deiters' nucleus,
scattered fibres show in the brachium'conjunctivum, lying in
' a plane perpendicular to the fibres of the latter, and 80 con-
trasting strongly with them.  These fibres are farther dorsal
in each succeeding section downward as far as the nucleus
fastigii, dorsal to which a well marked decussation is visible
(Figs. 3 and 2).

Fig. 5 represent8 a.longitndinal section taken through the
area of the vestibular nuclei.  The lines 66 on the transverse
sections represent approximately the plane of this section.
.--All of the vestibtllar nuclei, the nucleus nervi vestibularis
medialis (with the part of it which I have designated nucleus
Y), the nucleus of the descending vestibular root, the nucleus
nervi vestibularis lateralia and nucleus nervi vestibularis
superior, are shown.
Very little of the nucleus nervi vestibularis superior shows,
however, in.asmuch as this nucleus lies for the most part dorsal
to the plane of this section.  It will be seen that there is a
well marked group of fibrea B running obliquely forward8
from the region of the nucleus nervi vestibularis euperior.
These fibres have been traced on both series, and the area they
occupy is represented in the general diagram (Fig. 1, z).
They extend between the nuclei of the nervus trigeminus and
the raphe. Toward the floor of the ventricle they pa88
through the nucleus nervi vestibularis superior, a8 is shown
in the diagram. They decussate in the raphe dorsal to the
fasciculus longitudinalis medialis.  A8 to their further course
it is impossible to say from these sections.

XWVUS Coc?hlecB. The areas corresponding to the nuclei
of the nervus cochlea are illustrated in Fig. 1.  It is inter-
esting to note that the nUCleU8 nervi cochlearis dorsalis is
continuous with the nucleus nervi cochlearis ventralis and that
the transition from the one to the other is very rapid. Figure
6 represent8 a reconstruction to show the relations of the

cochlear nuclei to the corpus trapezoideum and the complex
of the nucleus olivaris superior.  The nucleus nervi cochlearis
dorsalis begins just above (anterior to) the nucleus nervi
hypoglossi. It is in the dorso-ventral direction a long, narrow
nucleus, the apparent breadth of the area representing it in
the diagram being due to the fact that it curves somewhat
around the corpus restiforme.  Its size and general character
are illustrated in Fig. 2.  Both the section and the diagram
show how far lateral it lies, though it by no means extend8
80 far lateral a8 the nucleus nervi cochlearis ventralis, a point
which is in disagreement with many of the figures in the text-
books. It ha8 comparatively few medullated axones in it, and
these run parallel to the !ong axis of the nucleus a8 seen in
transverse section. The division into three zones, a mesial,
middle and lateral, is clearly shown in Fig. 2.  This division
ha8 already been described by von KGlliker and by Sala.  The
mesial and ,lateral zones are rich in medullated flbres.*

In Fig. 6 is represented a flat reconstruction of the mesial
and lateral bundle8 of medullated flbres `of the nucleus nervi
cochlearis dorsalis.  The mesial bundle is marked m, and the
lateral 1. It may be seen that the areas corresponding to both
bundles run toward the middle line.

The fact that the root bundle of the cochlear nerve enters
the nucleus nervi cochlearis ventralis has been observed by
Held and Sala. It is interesting to note in Fig. 6 that the
area of the entering root bundle of the nervu8 cochles is
considerably superior (anterior) to that of the nucleus nervi
cochles dorsalis.  Both Held and von Kiilliker have described
the bifurcation of the cochlear root fibres. Ram6n y Cajal
baa observed the bifurcation both in the new-born mouse and
in the rabbit and says that it takes place in the nucleus nervi
cocblearis ventralis.

The two branches are, be states, usually equal in calibre, but
the ascending branches are short and end in the nucleus
nervi cochlearis ventralis.  On the other hand the descending
branches are longer and can be traced in a definite bundle to
the inferior part of the nucleus nervi cocblearis ventralis and
the nucleus nervi cocblearis dorsalis. He says that in the
mouse these fibres, at first scattered, 8oon form a definite
bundle, which can be traced to the inferior part of the
nucleus nervi oochlearis dorsalis. A bundle of medullated
fibres, apparently correspotiding to the bundle of axones
described by Ram6n y Cajal, has been easily traced in the
sections I have studied, and is shown in the figure (Fig. 6, h).
Near the entry zone of the cochlear nerve it consists of scat-
tered fibres, but it soon forms a compact bundle on the mesial
border of the ventral nucleus.  The bundle runs spinalwards
and at the same time so rapidly dorsalwards that in cross
section it8 fibree are cut almost longitudinally. The recon-
struction brings out the fact that it is connected with the
mesial zone of the nucleus nervi cochlearis dorsalis corres-
ponding to the area of medullated fibres m (Fig. 6).

The arrangement of the fibres of the nucleus nervi cochlearis
dOrsali in parallel lines ha8 already be& mentioned (Fig. 2).
In strong contrast to this is the appearance of the nucleus

I

*According to Sals the cells of the medal layer and the middle
zone give rise to the strife acusticse.


JOHNS HOPKINS HOSPITAL BULLETIN.

[No. 81.

aervi. cochlearis ventralis (Fig. 3).  The arrangement of the
cells and Gbres of the ventral nucleus in the form of a bssket-
work has already been described by Held, von K8lliker and
Ramon y Cajal. The latter divides the nucleus nervi cochlearis
ventralis into two regions, an inferior (tail) and a superior
(head).  In the hnman tissue which I have studied it is the
inferior part that is characterized by the basketwork.  In the
superior portion the cells are fewer and more scattered.
Indeed, the cells are so scattered and there are so many fibres
running to the corpus trapezoideum in this region that it is very
difficult to determine exactly in Weigert-Pal preparations the
superior limit of the nucleus. The area C. t. (Fig. 6) represents
the corpus trapezoideum.  Tt may be noticed that the lateral
boundary of the corpus trapezoideum is continuous with that of
the lemniscus lateralis.  In both series of sections a continuous
line of cells can be traced from the nucleus olivaris superior
to the nucleus of the lemniscus lateralis, so that it is impossible
to say where the nucleus of the lemniscus lateralis begins.  A
description, of the auditorv neurones of the second order can-
not be entered into at this time. The diagram shows very
clearly, howeger, the intimate connection of the nucleus
nervi cochlearis ventralis with the corpus trapezoideum and
superior olivary complex.  An examination of Fig. 2 shows
how few fibres are medullated at this period in the nucleus
nervi cochlearis dorsalis.  They are so scattered after leaving
the nucleus that it is very difficult to follow them far.  The
long distance between the nucleus olivaris superior and the
antesior extremity of the dorsal cochlear nucleus is another
striking feature of the diagram.

This study was undertaken at the suggestion of Dr. Mall
and Dr. Barker. I wish to thank them for constant advice
and suggestion. ,

BIBLIOOFUPHY.

1. Baginski: Ueber den Ursprung und den centralen Ver-
lauf des Nervus acusticus des Kaninchena Virchow's Archiv,
Bd. 105, H. 1, S. 28.-Ueber den Ursprung und den centralen
Verlauf de8 Nervus acusticus des Kaninchens und der Katze.
Virchow's Archiv, Bd. 119, H. 1, S. 81.

2. Von Bechterew, W.: Ueber die innere Abtheilung des
Strickkiirpers und den achten Hirnnerven. Neurol. Cen-
tralbl., Bd. IV (1885), S. 145.-Zur Frage iiber den Ursprung
der Hornerven. Neurol. Centralbl., Bd. VI (1887), 8. 193.-
Zur Frage'fiber die Striae medullares des verlgngerten Markee.
Neurol. Centralbl., Bd. XI, 1892, 8. 297.-Der hintere Zwei-
huge1 als Centrum fiir das Gehijr, die Stimme und die Reflex-
bewegungen.  Neurol. Centralbl., Bd. XIV (1895), S. 706.
3. Bumm: Experimenteller Beitrag zur Kenntniss des Her-

nervenursprungs beim Kaninchen. Allgem. Zeitschrift f.
Psych., Bd. 45, S. 568. -Experimentelle Untersuchungen iiber
das Corpus trapezoides und den HSrnerven der Katze.  Fe&
schr. zur 150 jiihr. Stiftungsfeier der Univ. Erlangen, Wies-
baden, 1893; Abstract Neur. Centralbl., Bd. XIII (1894), S. 448.

4. Cajal, Ramhn y S.: Beitrag zum Studium der. Medulla
oblongata des Kleinhnns und des Ursprungs der Gehirnner-
ven. Deut. Uebersetz. von Bresler. Leipzig, 1896.
5. Cramer, A.: Beitrage zur feineren Anatomie der Medulla
oblongata und der Briicke mit besonderer Beriicksichtigung
des 3.-12. Hirnuerven. Jena, 1894.

6. Flechsig, P.: Zur Lehre vom centralen Verlauf der Sin-
nesnerven. Neural. Centralbl., Bd. V (1886), No. 23.-Wei-
tere Mittheilungen iiber die Beziehungen des unteren Vierhu-
gels zum HBrnerven.  Neurol. Centralbl., Bd. IX, 1890, S. 98,
7. Forel: Vorhiuflge Mittheilung iiber den Ursprung des

Nervus acusticus. Neurol. Centralbl., Bd. IV, 1886, S. 101.
8. Held, H.: Die centralen Bahnen des Nervus acusticus bei
der Katze. Arch. f. Anat. und Phys., Anat. Abth., 1891.-
Die Endigungsweise der sensiblen Nerves im Gehirn.  Arch,
f. Anat. U. Phys., Anat. Abth., 1892.-Die centrale Gehorlei-
tung. Arch. f. Anat. u. Phys., Anat. Abth., 1893.-Ueber
eine directe acustische Rindenbahn und den Ursprnng des
Vbrderstrangrestes beim Menschen. Arch. f. Anat, u. Phy-
siol., Anat. Abth., 1892.

9. Kirilzew : Zur Lehre vom Ursprung und centralen Ver-
lauf der Gehornerveu. Vorlilufige Mitth., Neural. Centralbl.,
Bd. XI (1892), S. 669.

10. Von Kiilliker : Der feinere Bau des verlangerten Markes.
Anat. Anzeiger, Bd. VI (1891), S. 427-431; Handbuch der
Gewebelehre des Mensohen, 6 Auli., II. Bd. 1893.

11. Martin, P.: Zur Endigung des Nervus acusticus im
Gehirn der Katze.  Anat. Anzeiger, Bd. IX (1894), S. 181.
12. Von Monakow : Ueber den Ursprung und den centralen

Verlauf des Nervus acusticus.  Correspondenzblatt f. Schwei-
zer Aerzte, 1887, No. 5; Abstract in Neurolog. Centralblatt,
Bd. VI, 1887, S. 20l.LStriae acusticae uud untere Schleife.
Arch. f. Psych. u. Nervenkr., Bd. XXII, S. 1.

13. Onufrowicz, B.: Experimenteller Beitrag zur Kenntniss
des Ursprungs des Nervus acusticus des Kaninchens.  Arch.
f. Psych. und Nervenkr., Bd. XVI, S. 711.

14. Roller : Die cerebralen und cerebellaren Verbindungen
des 3.-12. Hirnnervenpaares. Die spinalen Wurzeln der cere-
bralen Sinnesnerven. Allgem. Zeitsch. f. Psych., Bd. XXXVIII
(1882), S. 228.

15. Sala, L.: Sur l'origine du nerf acoustique.  Arch. ital.
de biol., t. XVI, 1891, p. 196; also in Monitore zoologico
italiano, Florence, Ann. II (1891), and in Neurol. Centralbl.,
Bd. XI, 1892, S. 200.

LEGENDS FOR FIGURES.

fig. 1. Diagram representing flat reconstruction of the
nuclei of reception of the cochlear and vestibular nerves.
The line a, a represents the lateral wall of the ventricle; the
line b corresponds to the lateral outline of the corpus resti-
forme ; the line d, to d4, dl to ds, and the line 8, e, e correspond
to sulci in the floor of the fourth ventricle ; C. d., nucleus nervi
cochlearis dorsalis ; C. 2r., nucleus nervi cochlearis ventralis ;
the graduated line corresponds to the middle line of the floor
of the ventricle. Floe., Aocculus ; K. l?II, knee of nervus faci-
alis; L., medial portion of nucleus uervi vestibuli lateralis
(Deiters); L1, lateral portion of nucleus nervi vestibuli later-
alis (Deiters); ,l! together with y, nucleus' nervi vestibuli
medialis (Sch walbe) ; Nzcc. XII, nucleus nervi hypoglossi ;
Nut. l?L nucleus nervi abduceutis ; P. f., pedunculus flocculi ;
N; 7x.p. V., nucleus motorius princeps nervi trigemini ; N. 0.
s., nucleus olivaris superior ; iV. s. V., nucleus nervi trigemini
(sensory) ; N; c., root bundle of nervus cochleae ; .A? ug& root
bundle of nervus vestibuli; R. d. 12. ve., radix descendens nervl


15
   i





10







5 ~

FIG. 1.

Fro. 2.

v       .                ,
           FIG. 3.


258            JOHNS HOPKINS HOSPITAL BULLETIN.

vestibuli ; S., n.ucleus nervi vestibuli superior (Bechterew)
(area enclosed in the broad black line); Tr. s. n. t., tractus
spinalis nervi trigemini ; Y, nucleus y, antero-lateral portion
of nucleus nervi vestibuli medialis; z, decuasatio nervi
trigemini.

eralis (Gowersi); F. 1. m., fasciculus longitudinalis medialis;
A? XII, root bundles of the nervus hypoglossus; h'u. d.,
nucleus dentatus cerebelli ; A%. n. c. d., nucleus nervi cochlearis
dorsalis ; A? o. i., nucleus olivaris inferior ; iVu. n. v. m.; nucleus
nervi vestibularis medialis ; Nu. t. s., nucleus tractus solitarius ;
Py., pyramis ; R. d. n. vest., radix- descendens nervi vestibuli.

[No. 81.

NU.ll.KS
NUl.Kl.
k2f.

Fxo. 5.

Fig. 2 (corresponds approximately to line 3 on the diagram,
Fig. 1).  C. T., corpus restiforme; F. Q., fasciculns ventro-lat-

               FIG. 6.
Fig. 3 (corresponds approximately to line 4 on the diag. Fig.

1). Br. Conj., brachium conjunctivum; 17. T., corpus resti-
forme; F. 8., fasciculus ventro-lateralis (Gowersi) ; F. 2. m.,
fasciculue longitudinalis .medialis; N. c., nervug cochles ; N.
IX and X, nervu8 glossopharyngeus et vagus ; N%. n. c. v.,
nucleue nervi cochlearis ventralis; Nu. n. v. l., nucleus nervi
vestibularis lateralis (Deiters) ; .,A%. n. V. m., nucleus nervi
vestibularis medialis (Schwalbe) ; i%. n. v. s., nucleus nervi ves-
tibularis superior (Bechterew); Nzc. 0. i., nucleus olivaris in-
ferior; Nu. y., nucleus y (anterior-lateral portion of nucleus
nervi vestibularis medialis) ; P. f., pedunculus flocculi ; PY..
pyramis; R. d. n. vest., radix descendens nervi vestibuli; St. i. &
strstum interolivare lemnisci.

fig. 4 (corresponds approximately to line 5 on the diagram,
Fig. 1). Br. Uonj, bra&urn conjunctivum ; C! T., corpus
restiforme; F. 2. m., fasciculus longitudinalis medialis; F. Y.P
fibrse pontis ; N; c., nervus cochlem ; N; VIY, nervus facialis ;


DECEMBER, 1897.]

JOHNS HOPKINS H0SPIT.L BULLETIN.

259

I

N; vest., nervus vestibuli; Nu. ?t. VI, nucleus nervi abdu-
cent& ; Na. n. VII, nucleus nervi facialis ; Nu. n. c. v., nucleus
nervi cochlearis ventralis ; Na. o. i., nucleus olivaris inferior ;
Pg., pyramis ; S. g., subatantia gelatinosa; St. i. l., stratum
interolivare lemnisci ; Tr. s. n. t., tractus spinalis nervi tri-
gemini.

Fig. 5. (section 66, horizontal series). a, fibres extending
between lateral lemniscus and brachium conjunctivum; Aq. c.,
aqueductus cerebri ; ,8, decussating fibres of nervus trigemi-
nus ; C. i., colliculus inferior ; 0. r., corpus restiforme; C. s.,
colliculus superior; 1'. c., fasciculus cuneatus ; F. g., fasciculus
gracilis ; L. Z., lemuiscus lateralis ; A? IV, root fibres of nervus
trochlearis ; A%. a. c., nucleus alas cinereae; NW. n. c. d., nuc-
leus nervi cochlearis dorsalis; Nu. f. c., nucleus funiculi cune-
ati ; Nu. f. g., nucleus funiculi gracilis ; A%. n. v. Z., nucleus
nervi vestibularis lateralis (pars medialis) ; A%. n. v. II, nucleus
nervi vestibularis lateralis (pars lateralis); Nu. II. v. nz., nuc-

lens nervi vestibularis medialis ; iI%. 7t. v. s., nucleus nervi
vestibularis superior (Bechterew) ; Nu. n. XII, nucleus nervi
hypoglossi; iI%. VI, nucleus nervi abducentis; iVu. Y, nuc-
leus y (an&o-lateral portion of nucleus nervi vestibularis
medialis) ; R. d. a. t., radix descendens nervi trigemini ; R. d. 11.
vest., radix descendens nervi vestibuli ; Tr. s., tractus solitarius.

fig. 6.  Diagram representing flat reconstruction of nuclei
nervi cochlearis and corpus trapezoideum.  C. d , nucleus nervi
cochlearis dorsalis ; C. t., corpus trapezoideum; C. v., nucleus
nervi cochlearis ventralis; jb., portion of root bundle of cochlear
nerve running past the ventral cochlear nucleus to the region
of the dorsal cochlear nucleus ; Z., area occupied by medullated
fibres of lateral portion of dorsal cochlear nucleus ; 9n., area
occupied by medullated fibres in the medial portion of the
dorsal cochlear nucleus ; L. I?., region of lemniscus lateralis;
A? c., nervus cochleae ; AT o. s., complex of nucleus olivaris
superior.