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Studies in the wave mechanics of muscleVI. The areas of cohnheim are transverse sections of the cross striations of the striated muscle fiber

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1-1. T H E AKEAS O F C O H R ’ I I E I M ARE TRANSVERSE SECTIONS O F T H E
CROSS STRIATIOKS O F T H E STRIATED MUSCLE FIBER
EEEN J. CAREY A N D WALTER ZEIT
Oepurtnrent of dnnfoiny, ,Vat q i i e t t e F i e t z w s ~ t ySchool of Xcdzcine
THREE TEXT FIOCRES 4KD T W O P L A T h B (B’OIJR F I G C R E S )
KO tissue has been studied microscoy?ically more than cross
striated muscle yet there is inore confusion in our knowledge
of the constitution of’ the striated muscle fiber than any other
histologic structure. Every textbook on histology states that
the areas of Cohnheim wliich one observes i n transvcrsc sections, a r e cross sections of bundles of myofilrils separated
by irrcgular clear lanes of sarcoplasm. The striated muscle
fiber is evidently, according to current teaching, an cntirely
different thing in cross section than i t is in loiigitudinal scction. What happens to the alternate dark a n d light places
of the cross striations when a transverse section is made
through the striated muscle fiber? From textbook descriptiom they evidently disappear.
unchecked iiiterprctation
is then given which was origiiially prcsented 113- Kolliker
(1867).
After completing this study and coming t o certain conclusions, independently, we wcrc snrprisecl to firid that the
interpretation of the so-called areas of Colmheim, prcsciitcd
in this paper, is the one proposccl originally by Cohnhciin
(1865 a ) .
* T h e ohserrations reported 711 this p a p r constituted part of a demonstration
at the annual meeting of the American Association of Anatomists, Wasliiilgton
Cniversity, St. Louis, April, 1933.
343
344
EBEN J. CAREY A N D WALTER ZEIT
Nichts kaiiii in cler That niihcr licgeii, ais eiiiestheils die matte
uncl dunlilere, starker lichtbreclieiide Substane, welche auf
dem Querschnitt die Mosaik erzeugt, rnit der aiiisotropen
Briickc ’s, dcr Hauptsubstaiiz Rollett ’s zu iclentificiren, die in
cler Liingsrichtung der Faser die dunklere, stiirlrer lichtbrechencle Alantelzoiw bewirkt, aiiderritheils die durchsichligc,
gliiiizende, gitterfiirmige Zwischensubstanz cles Qaerschnittes
der isotropen Briicke’s, der Zwischensubstanz Roiiet ’s a n die
Seite zu stellen, die in der Liingsriclitnng die helleren uiicl
schwacher lichtbrechenden Zone11 erzeugt.
Colinheim (1865 b) denies the existelice of fibrils i n living
muscle p r o l o l h s m i n the following stateiiieiit :
Dass inan den Versuch maclieii werde, das Rild des RIuskelquerschnittes, wie es obeii geschildert ist, in Eiiiklang zu
setzcn niit dcr Lelire von clcr Znsamineiisetzung der Muskclfaser aus sogenarinten F i b d e n , das f iirchte ich iiicht. Icli
will hier iiicht iioch einrviai die Frage aufwerfen, die schoii
so oft urid iiiit so vie1 Recht deli Aiihiiiigern der Fibrilieiitheorie eiitgegengehalten ist, wem ist es namlich bis heutc
gelungen, aus einer lebenden Muskelf aser eine Fibrillc darziistellen ; halten wir uns lediglich a n den Qnerschnitt.
Coliiilieirn recognized the dark areas a s aiiisotropic substance
and the light areas as isotropic substance. His diagrammatic
figures, howcmr, i n 110 way conform to tile photomicrographs
presented in this paper. The original iiiterpretatioii, of the
significance of the pattern of the cross section of a striated
muscle fiber, proposed by Cohiilieirn, lias beeii lost because
of the adoption of the interpretation advanced b;v Kollilier
(1889).
Von den Restaiidtheilcn dcr Aluskelfasern sincl die B’ibrillen
und die Zwischensubstaiiz zuerst im Allgerncirieii zu besprecheii. Eine jede Muskelfaser besteht der €Iaupti$asse
nach aus eiiieni Biiiidei von feinen Fiiserchen, It-eiche als die
einzigen verkiirzuiigsf iiliigen Eleniente aueh physiologisch als
der michtigste Restaiidtheil derselhen erscheinen. Diese
Fibrillen bilclcii jedoch iiicht clurch die ganze Muslielfaser ciii
zusammenhangendes Riindel, vielmelir werden sic durch cine
in ziemlicher Mcnge vovhandene Zwischensuhstanz in unteiageordriete Eundcl eingctheilt. deneii ich den Nainen niluskeisaiilcheii, Columnae musculares, gab. J e iiach der Menge der
SIGNIFICANCE OF AREAS OF COHNHEIM
345
Zwischensubstanz und dem Reichthume derselben an interstitiellen Kornchen erscheinen diese Saulchen verschieden
gross und verschieden scharf begrenzt, doch stellen dieselben
im Allgemeinen rundlich eckige, bei Saugern 1, 3-2, 5 p, beim
Frosche 2-5 p breite Biindel dar, welche auf dem Querschnitte
frischer mit Kochsalz von *% behandelter Muskelfasern eine
mehr weniger deutliche feine Mosaikzeichnung erzeugen, die
von Cohnheim zuerst genauer beschrieben wurde, und auch
an Langsansichten besonders Gngsstreifiger Muskelfasern
meist bestimmt zu erkennen ist. Diese Fascikel und ihre
Querschnitte, die sogenannten Cohnheim’schen Felder, sind
bei allen cylindrischen Muskelfasern regelmassige, in der
ganzen Lange derselben verlauf ende Bildungen und dasselbe
gilt in diesem Falle auch von den Fibrillen ; bei spindel- oder
kegelformigen, dann bei verastelten Muskelfasern dagegen,
bei denen an den frei auslaufenden Enden je liinger um so
weniger Fibrillen und Saulchen sich finden, miissen beiderlei
Elemente im Innern der Muskelfasern in verschiedenen Hohen
enden, Verhiiltnisse, die jedoch an Langsansichten der Beobachtung sich entziehen, an Querschnitten dagegen aus der
Abnahme der Zahl der Saulchen und der Durchmesser einzelner derselben sich ergeben.
There will be no opportunity to correlate muscle form and
function, which was one of the first anatomic and physiologic
problems ever studied, and still remains unsolved, as long as
our ideas of muscular structure are inaccurate. The study
of the structure of the striated muscle fiber needs more
positive histologic evidence and less descriptive words and
alphabetic symbols. When this is done others may draw
their own conclusions.
The purpose of this paper is to present photomicrographic
evidence for the summary and conclusions of this paper.
Acknowledgment is made to Leo Massopust with thanks for
aid with the illustrations. All of the tissues for microscopic
section were fixed in Bouin’s solution, sectioned at 8j1 and
stained with iron hematoxylin and eosin. The photomicrographs were taken on Eastman’s infra-red plates.
THE A N A M M I O U REOORD, VOL. 64, NO.
3
346
EBEN J. CAREY AND WALTER ZEIT
OBJECTIVE DESCRIPTION
When muscular tissue of the crane-fly larva (Tipula wisconsinensis) is observed on longitudinal section (fig. 4), the
cross striations form irregular frozen waves of dark, anisotropic and light isotropic places. From one Z plate to the
next one is 18 p (average measurement). These Z plates are
evident in cross striations that have considerable length from
Z to Z line but are not visible in short ones, especially in those
of I to 3 p long. The Z plate in these very short cross striations is 0.1 to 0.3 p thick. This is near the range of the visible
limits of the microscope.
When muscular tissue is observed in cross section (fig. 5),
the irregularity and variability of the patterns of the dark
( Q ) and light (J) places are due to the transverse plane of
section through ripple-like cross striations observed in longitudinal sections. When these cross striations are observed
in longitudinal section by focusing at different depths in the
muscular fiber there may be a left or a right lateral shift or
alternate combinations of lateral shifts. Many irregularities
such as indentations forming pockets or grooves, and elevations forming conical protuberances and ridges are observed.
These cause the lateral shifts of the cross striations when
observed at different depths of focus. A transverse section
through such an irregular structure will reveal irregular,
variable patterns of its dark and light places which extend
throughout the transverse direction of the fiber. Figure 1
is a diagram representing longitudinal sections and corresponding cross sections through a striated muscular fiber
which has three patterns of the cross striations. A, convex to
the left, B, oblique plane and C, concave to the left. There is
no evidence of the stereotyped islands or areas of transverse
sections of myofibrillae, or sarcostyles called Cohnheim’s
areas described in textbooks of histology as constituents of
muscular fibers when studied in transverse sections. I n figure 4 certain cross striations are similar to longitudinal sections through a helicoidal pattern.
SIGNIFICANCE OF AREAS OF COHNHEIM
347
Heidenhain (’18) refers to the vernier appearance of the
striations of heart muscle interpreted as a spiral cut in longitudinal section. Tiegs (’35) concludes that the striae in
vertebrate muscles are single or double helicoids and not
transverse discs. The vernier appearance of Heidenhain may
be the result of a localized helicoidal structure or of a pyramidal formation of the propagated waves from the motor nerve
ending. These pressure waves are propagated ordinarily
first from the location of the motor nerve ending and spread
to the opposite side of the muscular fiber and toward the ends.
The waves on the side of the motor nerve ending or any place
where changes occur in the muscle fiber may be slightly in
advance of those travelling on the opposite side of the muscle
fiber. A slight shift in the change of the wave length or in
the time of propagation will produce patterns where the cross
striations are not in alignment. These designs of cross striations are continuously changing during life, comparable to
the shifting construction of the surface and surf waves along
the shore of the sea.
The pattern of the distribution of the dark and light substances of the cross striations is highly variable and irregular
with no aggregations of the so-called Cohnheim’s areas as
aggregations of transverse sections of myofibrillae. There
are denser places of high viscosity where the liquid protoplasm, resembling drawn out egg albumen, is lineated in longitudinal lines. These more viscid lines of protoplasm (fig. 6)
are in direct continuity with the rest of the protoplasmic fluid
and are not isolated, insulated filaments within a cable. The
patterns of dark and light places in transverse section are
directly due to the dark and light places in longitudinal section of the cross striations. These dark and light places are
alternate differences in the density of the liquid protoplasm
which extends transversely, produced by short fixed waves
of pressure within the muscular fiber.
Some additional possibilities in the distribution of the dark
and light substance of the cross striations are shown in figures 2 and 3. Figure 2 is a diagram representing a longitudinal section and corresponding cross section through the
348
EBEN J. CAREY AND WALTER ZEIT
cross striations of a striated muscular fiber. These have an
oblique, irregular wave-like pattern. A transverse section
would cut through different cross striations and through the
same cross striation in different places. The dark anisotropic
SCHEMA O F SIGNIFICANUE O F PROTOPLASMIC
PATTERNS I N TRANSVERSE SECTIONS
OF A MUSCLE FIBER
1.Longitudinal
section
2. longitudinal
section
Trmswrse section
w
rigures 1, 2 and 3
patches above the lines 3, 5 and 8 represent transverse sections through a conical protuberance on the fixed wave fronts,
corresponding to the numbered lines 3, 5 and 8.
Figure 3 is a diagram representing longitudinal sections of
wave-like and perpendicular anisotropic zones of cross striations and corresponding cross sections. In A, the cross section extends through the conical tips of the elevations on the
SIGNIFICANCE O F AZZEAS O F OOHNHEIM
349
fixed wave front of the Q substance. In cross sections these
would appear as irregularly rounded, oblong, dark areas of
anisotropic substance surrounded by the light lanes of isotropic substance. In B, a diagram of the cross section of
curved cross striations. The pattern of concentric circles of
the dark substance is produced by cutting through different
cross striations and through the same cross striation in different places. I n C the diagram of a transverse section,
includes only one Q plate. There is a tendency of uniform
stippling produced by transverse sections through the viscid
protoplasm h e a t e d by stretch.
The patterns shown in figures 5 and 7 are direct evidence
that the arrangement of the dark and light places of transverse sections is determined by the relationship of the anisotropic and isotropic places of the cross striations seen in
longitudinal seetions.
These observations on the structure of the striated muscular fibers of the crane-fly larva (Tipula wisconsinensis) have
been confirmed by corresponding observations on the striated
muscular fibers of vertebrates.
SUMMARY A N D CONCLUSION
1. The so-called areas of Cohnheim are transverse sections
through the alternate dark and light places, of alternate differences of density, of the cross striations. These cross
striations extend across the mature fiber observed in the
longitudinal aspect of the striated muscular fiber. The transverse section of the striated muscular fiber extends through
different cross striations or through the same cross striation
in different places. The fixed wave fronts of the transversely
placed cross striations, which are directed toward the end of
the striated muscular fiber, may have smooth, straight, convex, concave or oblique contours; or they may be highly
wavering with conical elevations, ridges and depressions.
The cross striations in longitudinal section have a highly
variable pattern in the slame and in neighboring striated
muscular fibers. They may have a complex intercrossing
350
EBEN J. CAREY AND WALTER ZEIT
pattern or in places resemble a helix. There is therefore no
uniform pattern of the dark and light places of the cross
striations when longitudinal and transverse sections of the
striated muscular fibers are studied. All of the geometrically arranged areas of Cohnheim of transverse sections of
striated muscular fibers we have seen illustrated are schematic
diagrams, comparable to those inaccurately conceived originally by Kolliker (1853, 1867, 1889).
LITERATURE CITED
COHNHEIY,J. 3
'
. 1865 Uber den feineren Bau der quergestreiften Muskelfaser.
Arch. f, Path. Anat. u. Physiol. u. f. Klin. Med. (Virchow), Bd. 34,
8. 615.
1865a Ibid., Bd. 34, 5. 617.
HEIDENHAIN,
VON MARTIN1918 Die Entdeckung der Noniusfelder in der quergestreiften Muskelfaser. Anat. Am., Bd. 51, S. 49-53.
KOLLIKER,R. A. VON 1853 Manual of Histology, vol. I, p. 243. Printed for
the Sydenham SOC.London, Translated by George Busk and Thomas
Huxley.
1867 Handbuch der Gewebelehre des Menschen. 5 Aufl., S. 297.
Leipzig.
1889 Handbuch der Gewebelehre des Menschen. 6 Aufl., S. 357358. Leipzig.
TWS, 0. W. 1935 Observations on the structure of striated muscle fiber.
Proc. Roy. Soe., London, Series B, Biological Sciences, vol. 116, p. 53.
PLATES
351
PLATE 1
EXPLANATION QB'
FIGURES
4 Photomicrograph (untouched), longitudinal section, striated muscular fiber,
crane-fly larva (Tipula wiseonsinensis). X 550. At the right of the figure, the
vertical edge, corresponds to a transverse section which cuts through fifteen Q
and thirty J plates of fifteen different cross striations separated by fifteen 2
plates.
5 Photomicrograph (untouched), cross sections, striated muscle flber, crane-fly
larva (Tipula wiseonsinensis). X 550. The irregularity and variability of the
patterns of the dark (8) and light (J) places are due to the transverse plane
of seetion through ripple-like cross striations observed in longitudinal sections.
352
S l G N I F I C A N C E O F AREAS O F C O H N H E I X
E B l N J. CAXRY A6T) U-ATA’ER ZRIT
353
T H E A N A T O X I C A L RECORD, VOL.
64,NO. 3
PLATE 2
EX€'LAiTA'iTOV
OF FIGTJRES
6 Photomicrograph (untouched), part of a longitudinal section and a n ciitire
neighboring cram section of striated muscular fibcrs, wane-fly lama (Tipula
misconsinensis). X 950. The pattern of the distribution of the daik and light
substance of the cross striations is Iiighlp variable a i d irregular with no aggregations o f so-called Cohiiheim 's areas as aggregations of trwnwersp sections of
i m yofi bri 1 he.
7 I'hotonricrograph (natonchrd) cross sectinn o f striated muscle fiber, cranefly larva (Tipula wiscoiisineiiais). X 970. l'liis is as near a transverse section
as it is possible t o obtain near the end of the muscle fiher. The transverse
liiieation of dark 2nd light places is what would be predicted of a transversc
section tlirouglr difierent croes striatioils seen in longitudinal sections nhic-h are
inclined in iclatiori t o one another.
354
STGXTFICANCE O F AREAS O F C O I I N I I E I I I
E B F S J. CAREY AND WALTER ZEIT
PLATE 3
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