Huygens Institute - Royal Netherlands Academy of Arts and Sciences (KNAW)
Citation:
S. de Boer, On the structure and covering of the trunk-dermatomes of the cat, in:
KNAW, Proceedings, 18 II, 1916, Amsterdam, 1916, pp. 1133-1146
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-1-
1133
.
,
Now, in the 'prebent investigation it has be,en proved that manganese
ions (MnOO) also act as a positive catalyst in the oXldation of tartaric
acid, lactic acid, malonic acid etc.
Thus light and manganese ions (MnOO) play tlle same role in these
oxidaiions with KMnÜ 4 •
Since numerous chemical actions have been shown to be markedly
accelerated by light, hence light rnay be I'egarded as (l po"litive
catalyst of great generality.
Pl'esiclency College Calcutta. lmpe7'ial
Co~lege
of Science, Lonclon.
Physiology.
" On the structw'e and cove7'il1g of the tl'unkclermatomes of thp cat". By Dr. S. DE BOEIt. (Commumcated
by Prof. G,
.
VAN RIJNBHRK),
(CommuOlcated"in the meeting of December 18, 1915) .
The investigations of EOKHAHD' haye al ready pl'oved that two
adJoming dermatomeb partly cover each other. Tbe meaSlll'e, iJl
WlllCh this covermg takes place, conld up to the present moment
only be ascertained by ca!rulatlOn It was not yet pObslble to do so
experimentally, becatlse with OTle and the same al1lmal two adjoming
del'matomes had nevel' yet been determined by physiologlcal methods
of' invesligatlon, The method of iso!ation, lllthel'to most followf'd,
by whlch towar(b the bead and the tall of one hind root two
we re cut, excluiled, as a matter of cóu;L'se, the posslbihty of determming two adjoining del'matomes. In 1911 howevel' DUSSER DIn B \RENNI!.
invented a new method for the deteL'luination of dermatomes. Tlus
method is fOl1ndeu on the fact (hat wlth local poisol1lng of tbe spmal
cOld on the spot wh ere one !lllld-root entel's, the del'matome belongmg
to it, shows a syndrome consistmg of three sorts of phenomena, to
which belongs a, o. also hypel'l'etIexlOn. DUSSER DE BARFNNE moislened
the spot where it entel's with a piece of cotton wool dl'enchecl 111 a
colonred Rolution of strychnine (L % ) that had pl'evlOnsly been
sqneezed out. He cOllld then easily limit (he hypel'l'eflectol'J tield
of Rkin. Accol'ding to this method BAHI~NKlt. detel'milled a.o. the
dermatomes of the hind leg with the dog, anel found in tlus wa)'
fields of skin, cOl'l'esponding with tl}e dermatornes il\ tlle same kind
of animal, e1etermined by WINKI,I~R anc! VAN RWm:ERK according to
the isolation methoc!. KU~SSENS e1etel'lnined the clel'matomes wltll cais
chiefly according to lbe strychnine-isolation-method. He applied the
strychnine-method of DUSSEH DE BAÏU,NNE combined with the isolationmethod. On both sicles of the mOlstened root he cut Ol1e Ol' two
roots .. In this way he determined in a cat the root-field of thoracalis
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-5-
---------1137
This figul'e makes us_ already sUl'mise tbat part of each dermatome
can be covel'ed br more than one. Fo!' this reason I have dete!'mined
1'0WS of -adjoining' dermatomes with different cats. I found then, that
three dermatomes from the thoraco-Iumbal l'egion have a l'ather
large strip of skin in common; this strip which is ra ther narrow
at the dorsal mediau Hne, ventrally increases in width.
In this w~.Y I determined of the cat, repre~ented from the dOl'sal
side in Fig. 2 and from the ventral side' in Fig.?, the de~'matomes
of th'oracalis 12 and 13 and lumbalis 1, 2, 3 and .,1: I obtained
the.se six dermatomes, by always cutting the hind-root of the
indicated dermatome and then determining the adjoining dermatome
according to the stl'ychnine-method. So I obtained a se'rÏes of lines
on 'the skin' as bOllndal'ies of the del'matomes in such, a way that
every time' both the antel'ior and the postel'ior boundary of each
del'matome moved a little farther. At the ventral side (Fig. 3) I
have made white a part that is cover~d by J dermatomes. ,In order
to elncidate these figures .I haye made au onÜr~ly ·fin~~h.ed preparation of that pal't of the skin on which these del'matomes oCCU!', and
made a, sketch of the extended figul'e of the skin. This sketch is
,repl'esented in Fig 4. I have indicated the anteriOl: and.the posteriol'
boundary of each dermato~e on the di)J'sal si~e by thè 'figures that
indieate the roots. If now we examioe the eovering' of. the field, of
lumbalis 1, we finu the part that is "indicated by tl'ansversal dashès
covel'ed by lumbalis 2 ,and 'thoracalis 12 an~ 13. The'piéce indicated
by longitudinal dashes is only covered by thoracalis 1~., The othei'
part of the dermatoI!-le of lumbalis 1 is partI)' covered' by one,
,partly by two del'matomes.
We see likewise in this represenlation, that the dei'matom'~s
lumbaiis 3 ~nd 4 deviate especially in the ventral part considel'ably
in a pQst€ll'ior dir'ection. fIer:e wè receive :indeed' :the '!mpl:~ssiQn as
if 'tlll'ough the developrnent of the hindlegs these dermatomes have
been dl:awn . backward .. (SHERIUNGToN). 1'he anterio~' 't>Ollndary of
111l~bal.isr' 3 c'ûts', eonseqtielitly"the posteI'~Ol' boundaries' of l' mid 2 ..
It is to be attl'ibuted to' Wis fact, tliat these two: del'matorriës cover
in ,fIle vent1'al' part those lying~ in front óf them less completeI)':
Moreovel' I fOllnd, that in the middle of the trunk the covering
of the venti'al side is strongest. We see' ü; titis' figtll'e thát th'oracalis
12'·and,lunibalis 2 ,have 'one' strip in' eommon beg'inning' at 'rhe
laterai si de 'and" widening"' 'vEmtl'alwal'd. It' ap'pears 'éonsequeiltIy
that' dermatomes' not :covel'ing ·èach 'other dorsally' earl do so io th'e
ventral', :side. MeasUl:em'ents'
the" rrÏ.ütllal eovering" ·.or' these 6' root.,
fields' taught me that· at thé dOl:sa( m'edianline:,
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1138
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Fig. 4.
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the field of thoracalis 13 covers th at
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At tlle ventral medianline the eoyering 1'01' the fir'st 3 fields was
certainly mnch greater, not however fol' the 2 last fields. These two
fields run in a strongly backward direction, as I commullicated
already previoJ,.lsly. At tbe yentral side these two fields are neither
entil'ely complete. The strychnine fields namely often show themselves imperfectly at the ventral side. Jt seems to me that the so
-7-
1139
much stronger outgrow of the dermatomes at the venh'al side of
the body has a special signification, and cannot be explained onIy
by the differences in length of the dOl'sal and the ventral medianline
I
of the body.
I think I must find the signification of tbis fa~t in the physiological relations existing in the ventral ,side of the body In opposition
to the dOl'sal one. It is certamly clear, that each animal receives
more stimula from the outside world at the ventral side than at
the dorsalone. The most primitive functions of life as roition and
buckling of animals occasion irritation at the ventral side.
"Umklammerungsreflex" can during a certain period be easlly
bl'ought about with the male frog by a blunt irritation of the
sternal part of the skin. Resplration gives rise to oscillation
of the thorax to the front; the intestines of the abdomen stretch
the skin here and in this way reflectorICally give rise to atension
of the abdommal muscles. The two extremities of the tractus intestinalit, are at the ventral side. Consequently it IS clenr that exactly
at the ventl'al side of tlle body the usual, normal physiological
functions take place.
But there is stIp more. The animal that attacks its prey or enemy
jumps upon them with the ventral side, the mother animal encloses
her young ones with the ven/ral side of the body. All vital functlOns are performed at the ventral side of the body, the dOl'sal sIde
is of no account.
Stimulants consequently always react onlyon tbis side of the body.
For this reason the nervous and orgamc (l'eceptol'icaD tissue develops
Itself here more ener~eticalJy, and we find here a greater extension
of the dermatomes than at the dOl'sal side. The stronger anatomical
development is here consequently a result of the increased physiological function.
In order to be able to apply the method indicated b,r. me for
the determination with one experimental animal ot sevel'al adjoining
dermatomes, we must be qnite certain that the strychnine method
is in every respect reliable. It might indeed be that the number of
dermatomes obtained is too great, because the poison has, not
remained local, aud an adjoining dermatome has for this re as on become
entirely or partially involved In the hyperreflexion. The fact that the
strychnine-dermatomes formd by DUSSER DE BARENNE for the hindleg
of the dog corresponded with those of WINKIJER and VAN RIJN.BERK,
found accol'ding to the isolation-method,' speaks strongly for the
filet (hat the influence of tlle strychnine remains local.
-8-
11411
I I",,·e >Iill "'0"· "'·,·"rfuel) I'ullli"col ,J.~ '·Ali.lil.'" or lhi,:",cohoo.
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1141
This' is thérefore of gréat interest l;>ecause in this way the factor of
vaJ'iability is excluded, which' certainly plays u. part, when we -use
the separate del'matomes' .of different animals for it. We can also
1
apply this method to ascertain w hether there is any connection
between the. pigmentation of the skin and the. dermatome-covel'ing,
and . what cOllnj3ction there exists 'between these. The selection of
snch animals as are fit for this purpose, must, in my ovinion, lead
to areliabie s6lution. T4e connertion that might exist betwe~n the
lines of LANGELo\AN and tlle arrangement of the dermatomes can
now be studied mOl'e directly. 1\1y experiments prove with certainty
what was al ready demollstrated by KLESSENS fol' one case viz. that
not only two adjoining dermatomes cover each othel', but that there
exists also covering between two that ,are sepa1'ated, from each other
by a third o~e. I found even also a~ Jhe venh'al side co~eril1g of
four derrnatomes. Now the question rises whelher these covering~pots of more ~han two dermatomes rorrespond with thqse' parts, of
the skin, wher~ under normal eonditions hyper~lgesy. ex~sts .
. . This problem can now likewise be mo~'e dirertly studied ..
. Fig, 5 gives a representation 'of the mutl!-al covering of the 1'oot~elds in the thoracal region.
,
The spinal-cord in the thora~al region of this cat was first
laid bare to a large extent. First I moistened the spinal-cord behind the
13 th thoracal root with a solntion of slllf. strychnine,(1 % )' The
liyper~'eflectory field ,that I discove~ed, is fou:gd bet ween the lines 1
and 4. Then I cut the 13 th thot'acal-root through and determined
the field of thoracalis 12 in ·the·samë way. I now cnt every time
the root of the determined fiE'ld' ~nd, look~d for the field, that follows
immediately in a fl'ontal direction accol'ding to the strychn~ne lllethod.
In th is war I found the field of _
•
l
thoracalis, 13 betweell lines 1 and 4
12
6
2.
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"
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" 8
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Two fields viz. those of thoracalis ,1.1 and
~re re'presented h81'e
with the covering of the adjoining !ields: Let us now malte 'a close
inspection of thé field of thol'acalis 11. lts posterior boundary is
constituted by line. 3, the anterior boundary by line 8, Line 4 is
the anterior bou'ndal'Y ,
of thoraéalis
13 and line
.
. 6 th at of thoracalis 12.
I
- 10 -
10
1142
The lines 5 and 7 constitute
in the same way the posterior
boundaries of thoracalis 10 and
9. Th~ scheme of fig. 6 is to
l'epresent this dermatome with
the coverings. The anterior
boundaries of thoracalis 13 and
12 and the posterior boundaries
of 10 and 9 are indicated by
the ordinal figure of these
dermatomes.
Now we find; that the derc, e, cl, is covered
matome-part
I·'lg. 6.
by 13 and 12, likewise b, g.j
(Dermatome of 'l'horacalis 11).
by 10 and 12 a, It, k by 9 and
10. Tbese 3 strips are consequently innerved along three hind-roots.
Between those are two strips of innervation by 2 hind-root!).
We found wIth tbe dermatome of thoraealis 12 equal relations.
A dermatome of the th'oracal region contains consequently 3 strips
that are innerved along th ree hind·roots. Two of these are found at
the edges, whilst the third is on the ('entre of the dermatome.
The nllmber of &trips that are jnnerved by 3 hind-roots is however
equal to the number of dermatomes, for each of the covering strips
of 3 fields lies on the centre of a dermatome, but likewise at the
edges of two adjoinmg dermatomes. So the strip b, g, j, th at is
innerved from the hind-roots 10. 11, and 12; in the centre of rootfield 11, at the anteriol' edge of field 12 and at the posterior edge
of field 10.
The dermatomes determined here have most likely not appeared
eompletely at the ventral side. At least I did not find here anywhel'e
4 dermatomes covel'ing eaeh othel'. Often the strychnine-fields are less
sharp and dlstinet at the ventral side. In many othel' determinations I did
find tbis co vering of'.J: tields ventrally. If this had here also been ,
tbe case, c, e would have cut the line b,j and g, b the line a, h.
Before'l had found the method of determining the covering of'
the l'oot-fields desCt'ibed above, I had all'eady reflected on another
method which bas only a theoretic~\i value. lf namely the skin is
irntated on a detinite spot, action-clU'rents must flow to the central
nervous system along more than one hind-root, in case there is
covel'ing. Now we ought to registrate these action-currents by means
of two string galmnometers. If now, when irritating on one definitè
spot, we ean deduct action-currents from 2 sllccessive hind-roots;
h§
te
- 11 -
1143
toe' cqvering would likewise be demonstrated experimen1ally. This
,however lias only v~lne as a theoretical method and could not
experimentally be applied. For the action-currents flowing from one
spot of the skin to tbe centra} nervous-system are certainly much
too weak to be conducted to the string galvanometer.
I have bowéver obviously proved by a circuitons way in my
experiments dest!ribed abo\"e, that aftel' irritation of one part of the
skin, action-currents mmt flow from each part of the skin to the
central ner,'ous-system at least along two hind roots. For if I have
determined with the cat of Fig. :1 t11e root-field of thoraealis IX,
the hyperreflectory field disappears, aftel' tbe bind-root of tboracalis
IX bas been cut. If tb en I moisten the spinal cord behind bind-root
X part of the root-field of thoracalis IX becomes again hyperreflectory
(this part has been hatched in tbe figure). Consequently action-currents
will flow to the central nervous system from this hatcbed skin-field
both along the bind-root of thoracalis IX 'and that of thoracalis X.
'* * *
If we isolate adermatome PJ', cutting on elther si de two or th ree
hind-roots, how is then the division of the separate radicularia of
whieh each bind-root consif1ts over tbe dermatome belonging to it.
WINKJ,ER and VAN RIJNBERK found with regal'd to the hind-roots,
that, if one bun die had remained intact, the sensibility continued
over a field, that as 10 form and extent could not be distinguished
from the field that had been fonnd aftel' isolation of the enth'e root.
DUSBER m~ BARENNE mqislened tbe spot of entrance of' two fila radicularia of one dorsal root with a solution of strychnine (1%) and
obtained then tbe complete strycbnine-dermatome.
1 have stlldied this problem again for the strychmne-dermatomes.
If we try to solve this question, we must dit'ect our investigations
to root-fields th at äppear in thei1' full extent, and in the second
place we must be sure that the stimulant applied can be applied
strictly locally. The strychnine-isolation can, satisfy these two demands
as mucb as possible. I pl'oceeded hereby first in a diffel'ent way trom
that of DUSSER DE BARENNE and arranged my investigations into this
subject in the following manner: Aftel' I had laid bare the spinalcord for a suffieient length and opened the duraJ I cut cranially and
caudally from one hind-root two or three hind-roots. rrhen I de ter_
mined according to the strychnine-method the root-field of the isolated
root. When I had then obtained a shal'ply limited field, J cut at the
anterior or the posterior side of this hind-root either some radicularia
or all ,but one Ol' two. The result w~s then such, that a strip of the
74
Pl'oceedings Royal Acad. Amsterdam. Vol. XVIlI,
/
- 12 -
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- 13 -
-----------------
-- ----_.------
1145
the adjoining ones do not take part in it. Indeed if every rootbun dIe occupies t11e entire field of the dermatome, how can we
then imagine, that by trauma of the spinal-cord or the hind-root the
del'matome partly does not appeal'. Trauma of part of the spinal-cord
or the hind-root would not be injul'ious, as the unimrt parls were
sufficient to supply an entire dermatome.
I am of opinion ~hat tbe advantage of my method hes in the fact
that by the strychnine-method 1 obtain dermatomes that are most
likely complete alld that by touching tlle hairs with a pencil I can
entirely localise the stimulants. These two conditions must be sa.tisfied
in order to obtain any certainty of the division of fhe radicularia
in the dermatome.
Aften'Val'ds I followed tbe method of DE BAHENNg, bnt then first
I moistened that part of the bpinal; cOl'd that ,was lying behind the
anterior or posteriol' fil. ra"dicnlal'e of a root, aftel' which the spinal cord
behind the whole root was moistened. Pl'eviously towal'ds the head
and the tail :l, 2, or 3 adJoining roots had been cnt. Ab an example
I give here fig. 8. I moisiened wUh the cat of this figure of
Thol'acalis 13 the spimtl cOId behind the anteriol' fil. radiculare with
1 0 / 0 sulf. strychnine .. The hyperreflectory field that I obtained lies
between the lines 1 and 3. Therellpoll I moistened the spinal cord
behind the whole root. The field then extended posterionsly as far
as line 4. '1'he field I 'obtained had noV\'" become 11/3 times as large.
Thereupon I cut all the radiculal'ia but one, I left tile most posterior
one un,toncheci. The tield that I obtained now, is enclosed by the
lineb 2 and 4. Oonsequently the central zone would here be between
the lines 2 alld 3 and the edge-zones between 1 and 2 and between
3 and 4. From this it appeal's distinctly that one exterior fil. radiculare
covers a great part of a l'oot-field, and that the field that is occupied
'by the central radicularia is mnch smaller.
One condition that must be satisfied with the'le experiments, 1S
certainly this, that we make our experiment on complete dermatomes.
For even with the strJchnine-dermatomes we are not always fully
certain of this completeness. Oaricature-formation often occurs here
likewise. At the ven Lral side e. g. these dermatomes often appeal'
imperfectly, and the edg,e-zone is vers of ten incomplete or absent.
And it is exactly this edge-zol1e in which thc difference of extension
is to be found between the field of the entire root and the mosi
extel'ior radicl1lal'ia.
At all events the results ()f my expel'iments seem to justify the
conclusion that the dermatome is not a unity but that it is composed of separate l'egions of 1'00i-bundles, arranged in a cranio-
74'1<
- 14 -
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- 15 -