Freiburger historische Bestände - digital

FOR INFORMATION.*)

*

Two errors of a peculiar kincl had, for a long time, m-
terfered with our ideas about the morbid processes in the
cranial cavity, viz: the supposition that the nerve substance
of the brain was »incompressible«, and the Suggestion that
the skull was »impermeable«.

In those cases in which morbid products of a certain
extent used to develop in the interior of the cranial cavity
it was generally supposed that the nerve substance — which
was believed to be incompressible — did not interfere with
such processes, and that only the liquid which was situated
between the brain and the skull — the so-called liquor
cerebrospinalis — became affected. It was taken for granted
that the liquid under consicleration was removed by the intracranial
morbid products, that it was compressed to a smaller
space, and thus placed under a higher pressure.

This increased pressure of the cerebro-spinal liquid was
called the »cerebral pressure«. — It was supposed that this
liquid was, particularly, exerting a pressure towards the sur-
face of the brain, and — as the cerebral surface was per-
vaded by the blood-capillaries which supplied the brain with
blood — the further supposition was that this pressure gave
origin to anaemia o f the brain. Finally, this cerebral
anaemia was looked upon as being the cause of the so-
called »Symptoms of the cerebral pressure«.

The fact, however, is that neither the nerve substance
of the brain is »incompressible«, nor is the skull »impermeable
«, nor are the »Symptoms of the cerebral pressure
« the result of cerebral anaemia.

The »Symptoms of the cerebral pressure« can be pro-
duced by any irritation of the brain.

As to the nerve substance of the brain, I was able to
compress it to the fourth part of its size, and even still
more, by means of a soaking compressing sponge which I iri-
troducecl into the cranial cavity of rabbits, without dama-
ging its Functions in the least.

The cranial bone, on the other side, represents a po-
rous plate provided with innumerable delicate Channels which
allow all possible currents to take their exit from the interior
of the skull and vice-versa.

With reference to the cerebral anaemia it must be
stated that in the case of intracranial diminution of Space
it cannot be produced for quite particular reasons.

When the diminution of Space is produced by a cir-
cumscribed focus — by a tumour — which is pressing itself
into the cerebral substance like into a soft mass of wax.
The blood-vessels, however, which run in the region of
the compressed part, are found far from being reduced,
but to the contrary dilated, owing to a certain reaction
which is peculiar to the walls of the blood-vessels.

When the intracranial diminution of space is a ge-
neral one, such as is produced by a pathological effusion
of liquid into the cranial cavity, cerebral anaemia can
not occur in such a case for the followino- reasons:

In the interior of the skull there are three Systems of
blood-vessels, and each of them is possessing a clifferent degree
of tension: the arteries with an average-pressure (in the
human subject) of 200 millimetres Hg.; the capillaries with

a much inferior degree of tension, which, however, was
rather near to that of the arteries, about 100 millimetres
Hg., and the cranial veins with the proportionally quite
extraordinarily low pressure of about from 1 o to 15 millimetres
H20.

It is quite elementary physical forces which cause a
liquid to flow towards the place which is under the lowest
pressure.

A pathological effusion of liquid into the cranial cavity
must thus first dischar£-e itself into the veins of the skull,
and this already occurs when the intracranial effusion has the
degree of tension of from 1 o— 15 millimetres HaO. — When
this tension is increased only a little, a State of overflowing
of the cranial veins must necessarily occur, and this is atten-
ded with two results which endanger life. On one side,
blood-serum escapes from the turgescent veins and penetrates
into the substance of the brain owing to which the so-called
»oedema of the brain« comes on, which, is known, to be a
fatal affection. On the other side, the increased afflux of blood
towards the veins over-fills the right ventricle of the heart,
Stretches its walls, and thus produces a mechanical obstacle
for its contractions, and owing to this severe derangement
in the very centre of the blood-circulation itself, death occurrs
also for this second cause.

The death which occurs on account of a double reason
is already certain when the pressure in the skull exceeds
but little the number of from ioto.15 millimetres H20, sud-
denly checks the development of a higher tension in the skull,
and thus it hinders the development of a cerebral pressure
which would produce an occlusion of the blood-capillaries of
the brain.

Thus the ancient doctrine ofthe »cerebral pressure« has
lost its ground, and has been replaced by the doctrine of
changfes which the substance of the brain sustains when com-
pressed owing to an intracranial focus, the pathology of the
compression of the brain.

We can distinguish three degrees of compression.

The firs.t degree comprises that compression which
the brain can support without any disturbance of function,
which has, clinically, a latent course. This degree is only
characterized by cha.nges of a material character. These
changes consist in, that the compressed nerve-elements ap-
proach to each other and are diminished owing to con-
densation of their substance. I have designated these changes
by the term of »condensation«. It is the evident expres-
sion of the compressibility of the nerve substance and the
evident refutation of the ancient view of the »incompres-
sibility« of the nerve tissue.

The third degree of compression is that owing to which
the nerve-elements are crushed, and destroyecl. The compression
in this case has the same effect as any other traumatic lesion.
The third degree of compression contains nothing particular
with reference to the pressure itself.

Between these two effects of pressure lies that of the
second degree. This pressure is too great not to influence
the nerve elements also functionally, and yet not strong
enough to crush these elements.

*) Lecture held in the Academy of Sciences of Vienna, on the 8th of Octobre 1891, on the occasion of the demonstration of the following tables bearing on the

rapid information over the surface of the brain in the living human subject. — Being an aid in surgical Operations and clinical lectures.
**) Adamkiewicz: Die Lehre vom Hirndruck und die Pathologie der Hirncompression. Sitzungsberichte der kais. Akademie der Wissenschaften zu Wien.
T. 88. 1883.

Gehirndruck in Eulenburg: Realencyklopädie der gesammten Heilkunde. 2. edition.
***) The same: Ueber das Wesen des vermeintlichen »Hirndruckes« und die Principien der Behandlung der sogenannten »Hirndrucksymptome«. Wiener akad.
Sitzungsberichte. T. 99. 1890.