Some histological aspects of the Os Cordis in <italic>Bos taurus</italic>

PDF

Download

Open document

Flip pages

Download a page range

Download transcript

Copy asset link

Request this asset

Transcript (if available)

Content SOME HISTOLOGICAL ASPECTS
OF THE OS CORDIS IN BOS TAURUS
A Thesis
Presented to
the Faculty of the Department of Zoology
University of Southern California
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
by
Donald R. Perry
June 1939
UMI Number: bP67130
All rights reserved
INFORMATION TO ALL USERS
The quality of this reproduction is dependent upon the quality of the copy submitted.
In the unlikely event that the author did not send a complete manuscript
and there are missing pages, these will be noted. Also, if material had to be removed,
a note will indicate the deletion.
Disssîtatifârî P ubi sN rig
UMI EP67130
Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author.
Microform Edition © ProQuest LLC.
All rights reserved. This work is protected against
unauthorized copying under Title 17, United States Code
ProQuest LLC.
789 East Eisenhower Parkway
P.O. Box 1346
Ann Arbor, Ml 48106 - 1346
T h is thesis, w ritte n by
Donald R. Perry
under the direction of Ala.. Faculty Committee,
and appro ved by a ll its members, has been
presented to and accepted by the Council on
Graduate Study and Research in partial fu lfill
ment of the requirem ents fo r the degree of
2 - 0 9 0 K
Master of Science
Secretary
Date ■ r m ? . . . ! ? . ? . ? .
Faculty Committee
Chairman
PREFACE
This study has many aspects unsolved, but due to limitations
of time and material, only certain large topics of pressing interest
were studied. The writer wishes to thank, especially. Dr. B.M. Harrison
for his true interest and for giving so freely of his time for helpful
criticisms and suggestions. The writer also thanks Dr. Daniel B. MacCallum
and Dr. Paul E. Patek for interpreting experimental data and for reading
preliminary drafts. Experimental material, helpful information and en
couragement was greatly appreciated from Dr. A. Foster and other veter
inarians connected with the State and Federal Meat Inspection Department.
TABLE OF CONTENTS
CHAPTER PAGE
I. INTRODUCTION ... ......... .............. 1
II. REVIEW OF LITERATURE................. 2
III. MATERIALS AND METHODS................................. 5
IV. OBSERVATIONS AND DISCUSSION ........................... 9
V. SUMMARY ................ 31
BIBLIOGRAPHY.................................. 34
LIST OF FIGURES
FIGURE PAGE
1. General Representation of the Ox Ossa Cordis at Various
Ages . . . . » . . . . ........... 11
2* Cardiac Bones Eight to Twelve Years Old ........... 12
3. A Typical Os Cordis . ....... ............ 12
4. A Left Os Cordis ......... 13
5. Diagramatic Relationship of the Os Cordis in the Ox Heart 15
6. Photograph of the Os Cordis in Situ in Beef Heart ... 16
7. Photograph of Convex Face of Beef Os Cordis in Situ in
Right Ventricular Wall ..... .. ... .. .. 17
8. Cross-Section of Haversian System from Os Cordis Two to
Three Years of Age . . . . . . . . . . . . . . . . 18
9. Longitudinal Section of the Ox Os Cordis Six to Eight
Years of Age ................ 18
10. Cross-Section of Ox Os Cordis Showing Scallop Structure 20
11. Primitive Haversian Space in Cross-Section of Ox Os Cordis 20
12. Cross-Section of Two Months Ox Os Cordis Prior to
Ossification .......... ............ .. 22
13. Cross-Section of Eight to Twelve Weeks Old Ox Cordis at
the Time of Initiation of Ossification ...... 22
14* Logitudinal Section of the Ox Os Cordis Three Months after
Birth Showing Ossification Advancing Toward the
Extremety . ......... 24
FIGURE PAGE
15* Cross-Section of Ox Os Cordis Three Months after Birth
Demonstrating Endochondral Bone Formation 24
16. Part of a Longitudinal Section of the Developing Os
Cordis . . . . . . . . .......... ....• 25
17. Cross-Section of an Advance Stage of Ossification of Ox
Ox Cordis about Four Months after Birth ....... 25
IS. Part of a Longitudinal Section of Ox Os Cordis Four to
Five Months of Age . . . . . . . . . . . 2S
19. Marrow Elements from Ox Os Cordis Five to Six Months of
Age . .. . . ........ 2S
20. Gold Impregnation of Ox Os Cordis Six Months of Age. . . 30
CHAPTER I .
INTRODUCTION
The cardiac bones in the heart of the ox are little known or
understood. In fact many zoologists are unaware of their regular occur
rence in the ox heart and their occasional presence in certain other ani
mals listed later in this paper. Veterinary anatomy texts mention the
occurrence of the os cordis but give small indication of any proof to
satisfy the nomenclature, os cordis, which would indicate that these car
diac elements are bone. No literature could be found concerning the
type of bone or method of development of the os cordis and there is little
said concerning the significance of these ossa cordis in the ox heart.
Since calcification may occur in the human heart, information
about the os cordis in the cow may assist in the interpretation of the
problems confronting investigators on the pathogenic calcification in the
heart.
It is the purpose of this investigation, therefore, to (l)
determine the shape and the relationships of the ossa cordis, (2) to
ascertain the histological structure of the ossa cordis in Bos taurus
and (3) to investigate the progressive differentiation of the ossa cordis
in the cow.
CHAPTER II
REVIEW OF LITERATURE
R. Retzer (1912), in a paper on the anatomy of the elephant
heart, mentions that Camper (1802) found cartilage in calf heart six
weeks old. This statement checks with the work done by the writer on
calf hearts of the same age. It was impossible to secure the original
paper of Camper*
King, Burwell and White (1938) in a paper on the anatomy of
the elephant heart, state that Putter (1918) had written a comprehensive
and detailed study of the comparative anatomy of the heart. It was not
possible to procure this research paper, but the reference is included
in the bibliography as a possible source of information on the subject.
The reference to the works of Galen (1510), Owen (1868) and Retterer
and Lelievie are included in the bibliography for the same reason.
King, Burwell and White, in their review of literature on the
subject of the elephant heart give no histological description of the
08 cordis which would distinguish between true osseous tissue and simple
calcium deposit.
Retzer, and King, Burwell and White found no os cordis in the
elephant hearts examined and attributed it to the poor development of
the trogona fibrosa in the particular specimens. The latter point
out that this is in direct contrast to the regular finding of a bone in
the ox heart, and its occasional occurrence in the heart of the sheep
and deer. In this connection Qualn’s Anatomy (1929) "The Heart'* and
3
Chaveau’s "Comparative Anatomy” (1930) mention the occasional finding of
an os cordis in the sheep, pig, camel, deer, giraffe, horse and in old
age, man. Often, however, true cartilage is said to be found in place
of ossified tissue.
All of the references examined concerning the position of the
08 cordis were in agreement, although different descriptional terms were
used. Quain (1929) and Retzer (1912) defined the os cordis as being
situated in the trigonum fibrosum dextrum and sometimes a much smaller
bone in the left trigonum. Retzer found that the left and smaller
may occasionally connect with the larger right bone. Furthermore, the
trigona fibrosa in any animal are described as two masses of connective
tissue which lie between the orifices of the mitral valves. Retzer
states that the left is near the periphery of the heart and the right is
in the triangle bounded by the aorta anteriorly and mitral and tricus
pid ring on the left and right side respectively. Sisson (1930) de
scribes the os cordis in the ox as being appositioned with the atrio
ventricular rings and irregularly triangular in form and states that the
left os cordis is inconstant. Cunningham (1923) maintains that the os
cordis in the ox is situated in the triangle between the atrio-ventri-
cular ring and aortic orifices. Smith*s "Manual of Veterinary Physiology"
(1912) states that the os cordis is in the ring surrounding the aortic
opening in the ox. Chauveau (1930) and Strangeway (1917) describe the
ox OS cordis as situated at the point in the heart where the arterial
rings are approximated to the auriculo-ventricular zones.
It is of interest that in all references mentioning the os
4
cordis, that nothing is stated of its probable function. Its position
would indicate a support to the walls of the aorta and the semilunar and
mitral valves. There is little indication gained from a review of
literature of a histological differentiation between true bone formation
and simple calcification. The tendency, however, seems to favor the
presence of true bone.
In searching for literature on the subject of the histological
differentiation of the os cordis in Bos taurus, it was found that there
was little literature directly available. Finding few references
locally, the writer contacted the following sources of information:
American Veterinary Review, Washington, D.C.
Bureau of Animal Industry, Washington, D.C.
Carnegie Institute, Washington, D.C.
Cornell University, Division of Veterinary Medicine
Ithaca, New York
Kansas State College of Agriculture and Applied Science,
Manhattan, Kansas
Museum of Natural History, New York City, New York
State University of Iowa, Iowa City, Iowa
The general responses received from these institutions were
references to the standard veterinary anatomies, reviewed in this paper,
and reports that no histological or embryological studies or references
on the subject were on file.
CHAPTER III
MATERIALS AND METHODS
The Bos taurus hearts examined in this study were obtained
from the Merchants Packing Company, the Goldring Packing Company and
Cornelius Brothers Packing Company in Los Angeles. These specimens
ranged from animals one day to fourteen years old. A total of forty-
seven hearts were procured for examination. These heart bones appear
in both sexes.
The intact cardiac bones were removed from twenty-four of the
hearts of animals ranging in age from one to fourteen years. The flesh
was removed from the bones by boiling for a short time in a strong
sodium hydroxide solution. This procedure was followed by bleaching in
a purex solution containing sodium hypochlorite. Finally, the specimens
were set aside to dry and whiten for several days. The ages of the
hearts from which the cardiac bones were removed and the number of bones
so prepared are given below.
16-18 months 6 specimens
3-6 years 6 specimens
6-12 years 6 specimens
12-14 years 6 specimens
Younger bones were also obtained varying in age from one day
to twelve months. These specimens were prepared for histological exam
ination as given subsequently. Prior to two months of age only cartilage
tissue was in evidence but ossification processes were evident in
specimens from two to six months of age. For this reason, two to six
month old tissue was emphasized. The number and ages of the specimens
examined histologically are given below.
4-6 weeks 3
specimens
6-8 weeks 5
specimens
2-3 months 5 specimens
3-4 months 5
specimens
4-6 months 5
specimens
All 08 cordis regions in hearts over six months of age contain
ed too much dense bone tissue to section without décalcification.
The microscopic slides for study were prepared in the following
manner:
Fixing agent:
Dehydration:
Clearing:
Infiltration:
The regions of the hearts containing the os
cordis were removed immediately after each
animal was killed and placed in Bouin* s
killing smd fixing solution.
All specimens were dehydrated in 24 hour
changes of ethyl alcohol varying in success
ive percentages as follows: 35, 50 and 70
per cent. The tissues were stored in the
latter. Tissue to be cleared, infiltrated
and sectioned was dehydrated in 24 hour
changes of 70, 80, 95 per cent and finally
absolute ethyl alcohol.
Before embedding in paraffin the tissue was
cleared from absolute ethyl alcohol as
follows: 50 per cent absolute ethyl alcohol
and 50 per cent xylol for 2 hours.
After clearing in pure xylol, the tissues
were placed in a 50 per cent bayberry-
paraffin (9 parts paraffin and 1 part bay-
berry wax) and 50 per cent xylol, for 6 to
12 hours, as all of the tissue was dense.
This procedure was followed ty 2 to 4
successive baths in the same mixture as above.
Embedding: All tissue was embedded in a one-ninth bay-
berry paraffin mixture.
Sectioning: Sections were cut from paraffin blocks at
thicknesses ranging from 6 to 20 microns.
Staining: The sections were stained with either of the
following:
1. Delafield* s haematoxylin, counterstained
with eosin.
2. Mallory’s triple connective tissue stain.
Mounting: All slides were mounted in Canada balsam.
Several longitudinal and cross sections of bleached cardiac
bone were prepared by grinding to a transluscent thinness on sand paper.
This was followed by finishing on a fine carborundum stone. Some of the
bone sections cut from the os cordis were embedded in plaster of paris
to facilitate grinding as the sections were small and difficult to handle.
Small sections may also be fastened to adhesive tape to keep delicate
tissue intact while grinding. The thin bone was mounted dry under a
clean coverslip held in place by a gurnned label.
A special technique was followed with some success from
McClung’s "Microscopic Technique" (1937) to demonstrate the processes
of young osteoblasts in the growing area of bone.
Briefly, this procedure was as follows;
Thin slices of os cordis regions four to six months of
age were fixed in 5 per cent formalin and treated in the
following manner:
1. Place in a 4 per cent solution of citric acid in dis
tilled water for twenty to thirty minutes in the dark.
2. Rinse in distilled water for several minutes.
8
3. Transfer to a one per cent gold chloride distilled
water solution for 20 to 30 minutes in the dark.
4. Place in a 33 per cent solution of formic acid in the
dark for 48 hours.
5. Rinse in distilled water.
6. Preserve in glycerin.
•The tissue prepared as outlined above was placed in a
freezing mixture, frozen with carbon dioxide gas and section-
ized with a freezing microtome at 6 miera.
The freezing mixture was prepared by dissolving 60 grams of
gum acacia in 80 c.c. of distilled water. These frozen sections were
mounted and stained with Delafield’s haematoxylin and eosin and set in
balsam.
The common procedure in investigating this problem was to mount
every tenth section cut So as to obtain a fair representation of the
tissue in the region of the ossa cordis. Both longitudinal and cross
sections were collected and studied.
CHAPTER IV
OBSERVATION AND DISCUSSION
Cardiac bones were found in all of the adult male and female
Bos taurus hearts examined. The general location of the bones does not
vary, but there are many variations in shape and development, as shown
in Figure 1. In most cases, however, the roughly triangular pattern is
maintained. The oldest specimens have the longest processes on the
posterior portion and the greatest thickness. Some of the specimens
from eight to twelve year old hearts appear vacuolated on the right con
vex surface thus showing signs of degeneration (Fig. 2). The marrow
cavity with its bony network may be seen by carefully examining the
vacuolated areas. The cardiac bones can be classed as irregular bone
and consist of a spongy interior covered externally ly a very thin layer
of a compact bone.
The ossa cordis are two small bones which develop in the
fibrous aortic ring on the left side of the heart. The right os cordis
is the larger bone and is roughly triangular in shape. Strangeway (1917)
designates the apex of the triangle formed as anterior and the base of
the triangle which bears two projections separated by a notch as pos
terior. Figure 3 represents a bone selected as being typical in re
presenting the structure and relations as found by the writer. The
left face is concave and the right face is convex. The left bone is
flattened on each side, much smaller than the right os cordis and has
the same general triangular form (Fig. 4)* The left bone is inconstant
10
and was found in only three of the older hearts ranging in age from eight
to fourteen years. They varied in length from one to two millimeters.
The right ossa cordis were three and one half to seven millimeters in
length, one to two millimeters in width and one tenth to three tenths
of a millimeter in thickness.
The right os cordis is located at the point of origin of the
aortic fiber, or as Sisson (1930) ‘ describes it, at a point where the
arterial ring is approximated to the auriculo-ventricular zones. The
anterior concave left face curves to the right and gives attachment to
the right posterior cusp of the aortic valves. The right surface of the
os cordis is pressed against the auriculo-ventricular opening and the
left surface is incorporated in the right wall of the dorsal aorta at
its origin in the left ventricle. The base or posterior portion is
directed upwards and in curving around the aortic opening, supports
the right half of the left bicuspid valve at its base in the auriculo-
ventricular zone^(Fig. 5 and 6). The right convex face of the os
cordis is shown by Figure 7 as seen when a portion of the wall is removed
from the right ventricle. When the left os cordis is present it supports
the left posterior cusp of the aortic valve.
Thin sections of os cordis made translucent by grinding
reveal that these cardiac elements in the Bos taurus are true bone. All
of the histological characteristics necessary to demonstrate true com
pact bone are in evidence.
Figure S illustrates a cross-section of the right os cordis
Figure 1
General Representations of Ox Ossa
Cordis at Various Ages.
(one-third natural size)
(1) Right Ossa Cordis 16-18 months
(2) Right Ossa Cordia 2-3 years
(3) Right Ossa Cordia 6-8 years
(4) Right Ossa Cordis 8-12 years
(a-b) left ossa cordis in relationship
with bone on right in each case.
F , 9urG.
Figure 2
. Cardiac Bones 8-12 years old
(natural size)
1. This bone shows vacuolated area on right convex
surface. The spongy interior structure is visible.
2. This bone shows signs of degeneration by its
vacuolated right convex surface and slender pro
cesses.
3. This specimen demonstrates advance signs of de
generation because of its small size and general
weakness of structure.
Figure 3
A Typical Os Cordis 2-3 years old
(natural size)
A. A typical os cordis
1. Anterior or apex
2. Posterior or base
3. Concave ];ight surface
B. This specimen is the same age as A but is atypical
in shape.
Ag ure 2 .
W I I V ^ I X -~J I I
UNIVE
Af g u re >5
Figure 4
A Left Os Cordis
(twice natural size)
1. Base or posterior portion
2. Apex or anterior portion
3. Convex face
e
s
i J H E T f
]T( fiiii
14
which shows an enlarged view of a Haversian system. The central black
area is a Haversian canal and grouped around it are the positions of
the bone cells represented by the lacunae. Between these circles re
presented by the lacunae are the lamellae or calcified ground substance.
A longitudinal section of the os cordis. Figure 9, demonstrates
a longitudinal portion of a true Haversian canal as represented by the
concentric circles of bone cells. The diverging tubes at each end are
the Volkmann’s canals which penetrate the Haversian systems and open to
the free surface of the bone or into the bone marrow cavity. Maximow
(1930) says that these Volkmann’s canals may pass over or connect into
Haversian canals and may be distinguished by the lack of walls of con
centrically arranged lamellar plates. It is possible to trace these
Volkmann canals to the inner or outer surface of the cardiac bone.
In a cross section of the os cordis under low power, it is
possible to demonstrate the basic lamellae (Fig. 10). The external
basic lamellae run parallel to the long axis of the bone. The internal
basic lamellae demonstrate the characteristic "scollop" structure present
in the os cordis. These "scollops" are the connecting structures of the
outer compact bone with the spongy bone trabeculae in the marrow portion.
These bone trabeculae can be seen macroscopically in the older heart
bones. A primitive Haversan space may also be seen in Figure 10.
Here, according to Maximow, osteoclasts have hollowed out a space in the
bone already present, and the area will become filled with bone marrow
and blood vessels. Later, he says, osteoblasts will move in from the
Figure 5
Diagramatic Relationship
of the Os Cordis in the Ox Heart
(one-third natural size)
1. Dorsal aorta
2. Left mitral valve folded back over left atrium
3* Left and right posterior semi-lunar valves
4. respectively
$• Right mitral valve
6. Left auricle
7. Ventricular wall
8. Chordae Tendineae
(Black area represents right Os Cordis)
i
Figure 6
Photograph of Os Cordis in Situ in Beef Heart
(one-third natural size)
1. Right mitral valve
2. Chordae tendineae
3* Left mitral valve folded back
4-* Remaining portion of auricle removed
in taking heart from the ox
5* Thick wall of left ventricle
6. Fat on outer portion of heart
7. Right 08 cordis in situ
Fi^oire. 6
Figure 7
Photograph of Convex Face of Beef Os Cordis
in Situ in Right Ventricular Wall
(one-half natural size)
1* Convex face of right os cordis as
seen from the right ventricle.
2. Tricuspid valve.

Figure 8
Cross-Section of Haversian System
from Os Cordis 2-3 Years of Age
(X256)
1. Haversian canal
2. Concentric lamella
3. Lacunae
Figure 9
Longitudinal Sections of
Os Cordis 6-8 Years of Age
(X50)
1-4 Volkmann* s canals
5. Haversian canal with concentric
rings of lacunae a and b
%
F ur e <3
. , ,
••- '4;. ,
m
19
periphery toward the center, become arranged in concentric layers or
lamellae around the vascular elements and a new Haversian system is formed,
The process is said to be continuous and serves to adjust the bone to
stresses and strains put upon it* Figure 11 is jÆiotomicrograiài showing
a primitive Haversian space with bone and bone marrow elements within*,
Longitudinal and transverse sections of the os cordis stained
with Haemoto^lin and Eosin or Mallory’s Triple Connective Tissue stain
demonstrate the presence of hyaline cartilage in all of the ossa cordis
taken from hearts five to eight weeks old* Os cordis areas from hearts
two to three months of age show definite signs of endochondral or car
tilaginous ossification* Sections made from tissue ranging up to six
months of age demonstrate the progressive development of the primitive
os cordis by replacement of hyaline cartilage with bone*
All of the os cordis specimens from hearts eight to twelve
weeks of age give histological evidence of the beginning of endochondral
bone formation* Some of the hearts were more advanced in the cartilage
replacement than others, but this is . consistent with the individual
differences and vsiriations found in the adult cardiac bones from animals
of the same approximate age. The fact that the ages could only be
approximated as the hearts were chosen during slaughter, may account for
some of the differences mentioned above*
Schafer (1929) describes endochondral ossification as occurring
in three stages:
In the first stage the central cells of the cartilaginous area
become enlarged and radially arranged in rows emanating from the center
Figure 10
Cross-Section of Ox Os Cordis
Showing Scallop Structure
(X50)
1 and 1*• Internal lamellae forming characteristic
scallop structure*
2* External lamellae
3* Primitive Haversian space*
4* Haversian system in intermediate lamellae.
Figure 11
Primitive Haversian Space in
Cross-Section of Ox Os Cordis
(X50)
1* Primitive Haversian space
2* Marrow elements
3* Bone cell in lamellar ring of new
Haversian system.
FigutG lO
Figure dd.
21
with fine granules of calcareous matter being deposited here in the matrix,
At the same time osteoblast cells underneath the periosteum are said to
deposit layers of fibrous material upon the cartilage and this material
becomes calcified. Furthermore^ as these layers are formed, some of the
osteoblasts are included between them and become bone cells.
Figure 13 shows a part of a cross section of the os cordis
taken from an animal eight to twelve weeks of age. The cells in the
middle of the cartilage are enlarged and the cartilage matrix between
cells in the lower portion of the photomicrograph is calcified. Osteo
blasts have deposited a bony layer just under the periosteum and in this
particular illustration some of the vascular subperiosteal tissue has
eaten its way through this bony layer into the calcified cartilage cells
leaving consequent marrow spaces. Thin layers of bone are in evidence
in some of the primitive marrow spaces.
The clear hyaline cartilage found in the region of the os
cordis at two months of age is shown in figure 12. The ossification
process has not been initiated in this illustration.
Schafer describes the beginning of the second stage of endochon
dral bone formation with the vasculated subperiosteal tissue eating its
way through the newly formed layer of bone into the center of the calci
fied cartilage. This same process is demonstrated in the os cordis as
seen in Figure 14-. The calcified cartilage is absorbed in front of this
invading tissue so that there are large spaces now occupied by embryonic
connective tissue, osteoblasts and many sinus-like blood vessels which
Figure 12
Cross-Section of Two Months Old Ox
Os Cordis Prior to Ossific^ion
(X62)
1. Connective tissue
2. Perichondrium
3* Hyaline cartilage
Figure 13
Cross-Section of 8-12 Weeks Old Ox
Os Cordis at the Time of Commencing of Ossification
(X50)
1* Connective tissue
2. Periosteum
3* Layer of bone deposited underneath
periosteum
4. Acidophilic layer of bone
5* Primitive bone marrow elements
6. Nests of enlarged basophilic calcified
cartilage cells.
Ï
Fi^ ore. dZ.
# k
. ' r
i .
' D "V " ,
V
X
:û
FicMure. iJ
23
have grown in from the outside* Osteoclasts are in evidence just pos
terior to the invading marrow elements and appear to be attached to the
various islands of calcified cartilage and newly deposited bone* Maximow
(1930) and Dodds (1932) maintain that the primary evacuation process is
accomplished by histolytic ferments produced by the elements in the
primitive bone marrow. Figure 15 is an photomicrograph of em area in
the primitive os cordis at about three months of age. The darkly stained
portions are basophilic remains of calcified cartilage. The lighter
staining acidophilic areas are newly deposited spongy bone. Osteoblasts
are those small darkly nucleated cells lining the newly ossified area.
In the interstices of this spongy bone material are the vascular and primi
tive bone marrow elements.
Schafer describes the third stage of endochondral ossification
as a gradual advance of ossification towards the extremities of the carti
lage. At the same time, he says, fresh layers of bone tissue are de
posited on the walls or septa of the marrow spaces and on the surface of
the new bone under the periosteum. Figure 16 is a photomicrograph which
demonstrates the above stage in endochondral ossification of the os cordis.
Schafer (1929) states that the advancement of ordinary carti-
loginous bone into cartilage always takes place by a repetition of the
same changes: the cartilage cells first enlarging and becoming arranged
in longitudinal rows, the matrix nearest ilie already formed osseous tissue
becoming calcified, and then the calcified cartilage being excavated from
behind the invading vascular tissue so as to form new marrow spaces.
Figure 14
Longitudinal Section of Ox Os Cordis
Three Months of Âge Showing Ossification Advancing from the Center
(X50)
1 and 1’. Marrow elements in primitive spaces.
2. Bone ^ *
3. Calcified cartilage
4. Nest of calcified cartilage cells
Figure 15
Cross-Section of Ox Os Cordis Three Months
of Age Demonstrating the Endochondral Bone Formation
(XlOO)
1. Primitive marrow elements
2. Newly deposited bone
3. Calcified cartilage
4. Sub-periosteal bone deposit
5. Layer of osteoblasts
6. Fibrous layers of the periosteum
7. Connective tissue
Fiqote. dS"
26
The septa, at first covered by only a thin layer of bone, becomes thick
ened by layers of bone deposited by osteoblasts. The advance condition
of endochondral bone formation in the os cordis is shown in Figure 17.
The cartilage cells enlarge, but instead of forming in rows of single
cells, form little clusters or nests of cells with small amounts of
cartilage matrix between adjacent cells which may or may not show evidence
of calcification. Dodds (1932) favors the view that in skeletal bones,
there is no calcification between cartilage cells in nests or in longi
tudinal rows, but that the matrix in between the cell groups is calci
fied and as this resists evacuation by the primitive marrow elements, it
is left as calcified cartilage islands that are later destroyed by
osteoclasts; the cellular elements having no calcium are easily dissolved
by the marrow elements. Maximow (1930) says that this distribution of
cartilage in clusters or nests is the result of their multiplication dur
ing the last jdiases of cartilage development. Hé says further that this
is due to rapid division of cartilage cells with little expansion or in
crease of matrix material and that each group arises from one original
cell. Dodds maintains that nests of cartilage cells are typical of
areas where growth is not extensive or of terminal ends of ossifying
tissue. Maximow and Dodds agree that the-absorption of calcified carti
lage matrix is affected by giant multi-nucleated cells contained in the
primitive bone marrow. Osteoblasts are said to originate at the same time
and from the same source as these giant cells which are cells are called
Osteoclasts.
27
Kie endochondral bone formation was present in Bos taurus
hearts six months of age. There was very little cartilage left and
if the groups of cartilage cells are indication of the last phases of
cartilage development as Maximow (1930) maintains, then the endochondral
formation will be terminated in a short time. A bone construction pro
cess does continue into adult life as the os cordis bones present at
sixteen to eighteen months of age are much smaller than those two and
three years old (Fig. l). Dodds (1932) points out that bone cannot
grow by interstitial growth and therefore retains proper form by deposition
of bone tissue at one point and removal of bone from another. Cross-
sections of adult bone two to three years old demonstrates primitive
Haversian spaces that have presumably been destroyed and digested by
osteoclasts. Maximow says that the tearing down and reconstruction of
bone is based entirely on the activity of osteoblasts and osteoclasts.
He says further, that bone reconstruction is always coordinated with local
mechanical conditions existing at the time and guarantees the greatest
possible rigidity of the corresponding part of the skeleton.
The bone first formed in the os cordis is spongy bone contain
ing irregular lamellae and no Haversisin systems (Fig. 14 and 1$). Figure
18 shows the marrow cavity in a cardiac bone about four months old. The
bony and cartilaginous tissue in the marrow cavity has been absorbed.
Along the outer sides a beginning of true compact bone is in evidence
with a central Haversian canal and lamellae about it. Osteoblasts can
be seen lined up outside the newly formed bone. Primitive marrow
Figure 16
Part of a Longitudinal Section
of the Developing Ox Os Cordis
#
(XlOO)
1. Primitive marrow elements
2. New bone
3. Calcified cartilage
4. Enleirged nests of calcified cartilage
cells
Figure 17
Cross-Section of Advance Stage of
Ossification of Ox Os Cordis of about Four Months of Age
(XlOO)
1* Primitive marrow elements
2. Nests of cartilage cells
3. Calcified cartilage matrix
m f É
M R #
c V ^ f
Fi ^ u re. i6
IF
1^ >
' V ' ■
Fi q u t - e. dT
Figure 18
Longi-U^inal Section of Ox
Os Cordis Four to Five Months of Age
1. Bone marrow elements
2 m Space between bone marrow and sub
periosteal bone.
3* Layers of osteoblasts
4» Subperiosteal bone
5* Beginning of Haversian system
6. Periosteum
7. Connective tissue
Figure 19
Marrow Elements from
Os Cordis Five to Six Months of Age
( X 3 5 0 )
1. Reticular network
2. Marrow cellular elements
m #
m :
s
Fi^uire. i&
i
# »
' v V i * .
I f
« »
» *
Figure, i.9
29
elements in a four to five months os cordis are shown in figure 19.
Figure 20 is a gold impregnation of cardiac bone about six months of
age. The black areas are bone, but some bone portions not so heavily-
impregnated show the lacunae with the canalicular processes.
In this comparison of the endochondral ossification of the
08 cordis with that of normal long bone formation, it is at once evident
that there is very little difference between the two processes. Some
sections of a os cordis, however, indicate that ossification starts in
the central portions of the cartilage, but advances toward one extreme
faster than the bone replacement process in the opposite direction. Cross-
sections of specimens five and six months of age show one end completely
ossified while the opposite end is nearing completion. In all stages the
nest formation of the cartilage cells is in evidence. This nest
formation is common in small bones of the skeletal system. The endo
chondral bone formation of the os cordis, however, is entirely post-natal
while portion, at least of long bone formation is foetal. Maximow (1930)
states that in short bones which are formed in cartilage a central point
of endochondral ossification may appear and progress from the center to
the outside. This is said to continue until only a thin cartilage layer
remains and when cartilage no longer regenerates and is completely used
up, the periosteum begins to deposit upon the exterior of the endochondral
spongy bone layer of periosteal bone. This is said to become compact
bone. The above process is not in evidence in -the ossification of the os
cordis, although it is a small bone. Osteoblasts appear on the interior
portions of the bone as well as the exterior even before the endochondral
Figure 20
Gold Impregnation of
Ox Os Cordis Six Months of Age
(XlOO)
1. Compact bone showing lacunae
2. Spongy bone densely impregnated with
gold
Ft ^ UlrG. Z O
31
replacement processes are terminated at either extremity (Fig. 18).
The ossa cordis in the Bos taurus has been found in all of the
cattle hearts examined and there may be two bony elements present, one
right and one left. The right os cordis is the larger bone and is lo
cated at the base of the aorta and strengthens the right wall of the aorta
at its entrance into the left ventricle as well as acting as a support
to the right and small portion of the left posterior semilunar valve and
right portion of the left mitral valve1 Both bones are roughly tri
angular in shape but the left bone is much smaller, very inconstant and
may or may not be attached to the right os cordis. When present the left
os cordis acts as a support to the left posterior semilunar valve.
The adult right cardiac bone is a true bone as evidenced
such histological characteristics as Haversian systems, Volkmann’s canals,
primitive Haversian spaces and basic and intermediate lamellae*
The right os cordis seems to progress through a regular cycle
of development in each animal and undergoes degenerative changes in old
age. Minor individual differences are in evidence and support Maximow
(1930) who states that bone reconstruction is coordinated with existing
mechanical conditions. These conditions would of course vary somewhat
in different animals.
The 08 cordis area in five to eight week old hearts is composed
of hyaline cartilage. All of the hearts estimated to be eight to
twelve weeks of age give evidence of endochondral bone formation. The
central portion of the cartilage of the developing os cordis is replaced
3^
first with bone and this process progresses toward both extremeties.
The cartilage is first calcified, then is excavated by primitive marrow
elements and finally bone is laid down on the remnants of calcified
cartilage between the nests of cartilage cells, typical of the primitive
08 cordis regions. This central mass of calcified cartilage with thin
layers of bone is removed presumably by osteoclasts in the primitive bone
marrow while compact bone is formed around the periphery of the bone. The
formation of Haversian systems is noted in the external portion of the os
cordis at a very early stage, even before cartilage replacement is com
pleted. The process of endochondral bone formation gives evidence of
completion at about six months after birth but the ossa cordis undergo
reconstruction and enlargement according to their needs throughout adult
life by a tearing down and rebuilding process, as evidenced by the
primitive spaces in adult bone.
The study of the os cordis has several interesting aspects that
could no doubt be profitably followed by research workers in the future.
A comparative study of the occurrence of the os cordis would undoubtedly
be promising in that some light might be shed upon its phylogenetic signi
ficance. Information of the os cordis in the cow and other animals
should assist in the interpretation of problems confronting investigators
in the pathogenic calcification of the human heart.
CHAPTER V
SUMMARY
1. The hearts of forty-seven cattle, ranging from one day to
fourteen years old were examined. Evidence of ossa cordis was found
in all over four weeks old.
2. The position of these cardiac bones is constant in that they
form the base for the attachment of the dorsal aorta to the wall of the
left ventricle and are cpnfluent with the auriculo-ventricular region.
3- The ossa cordis function as supports to the semilunar valves
and right portion of the left mitral valve; as well as strengthening the
aortic wall at its origin in the left ventricle.
4# The ossa cordis are irregular bones with an outer portion consist
ing of compact bone fend an inner portion consisting of spongy bone elements.
5. The right os cordis is a true bone as evidenced by the presence
of Haversian systems, basic and intermediate lamellae and Volkmann's canal.
6. The os cordis is pre-formed in cartilage, replaced by spongy
bone elements and later peripheral compact bone is formed.
7. The endochondral ossification is initiated at approximately
eight to twelve weeks after birth.
8. These cardiac bones reach their maximum development in cows
six to eight years old, and show evidence of degeneration in all older
specimens.
BIBLIOGRAPHY
Addison, W.H.F., 1936, Piersol^s Normal Histology. Philadelphia,
J.B. Lippincott Company.
Arey, L.B., 1917, "The origin and fate of osteoclasts." Anatomical
Record. 2:319-322.
Baker, R.J., Cytological Technique. London, Methuen and Company Ltd.
Bremer, J.L., 1927, A Textbook of Histology. Philadelphia, P. Blakiston’s
Son and Company.
Camper, P., 1902, Description anatomique d*un elephant mala. Paris,
Publie par son fils, A.G. Camper.
Conn, H.J., 1936, Biological Stains. New York, Published by the Commission,
Cowdry, E.V., 193S, 2nd edition. Textbook of Histology. Philadelphia,
Lea and Febiger.
Cowdry, E.V., 1935, Special Cytology. New York, Paul B. Boeber. 2 vols.
Cunningham, D.J., 1923, Cunningham*s Textbook of Anatomy (Edited by Arthur
Robinson) 5th edition. Baltimore, William Wood and Company.
Dodds, G.S., 1932, "Osteoclast and cartilage removal in endochondral
ossification of certain mammals." Journal of Anatomy, 50:97-116.
Galen, C.D., (1550), Anatomicus Adminstrationibus. Book 7. Latin
translation by Lyon*s. 1:295*
Galigher, A.E., 1932, Essentials of Practical Microtechnique. Berkeley,
Laboratory of Microtechnique, Albert Galigher, Inc.
Gray, J., 1931, Experimental Cytology. Cambridge at University Press.
Guyer, M.F., 1936, Animal Micrology. Chicago, University of Chicago Press.
Hartridge, H., and Haynes, F., 1932. Histology for Medical Students.
London, Oxford University Press.
Jordan, H.E., 1921, A Textbook of Histology. New York, D. Appleton and
Company.
__________, 1927, "Further evidence concerning the functions of osteo
clasts." Anatomical Record. 2:319-322.
^35
Jordan, H.E., 1925, "Varieties and significance of giant cells." Anatomi
cal Record. 31:51-6A.
King, R., Burwell, S. and White, P., 193S, "Some notes on the anatomy of
the elephant heart." American Heart Journal. l6:735-7^3•
Kingsley, J.C,, 1920, The Vertebrate Skeleton. Philadelphia, P. Blaki-
ston*s Son and Company, Inc.
Lee, B., 1937, Microtechnique. Vade Mecum. Philadelphia, P. Blakiston* s
Son and Company, Inc.
Maximow, A.A., 1930, Textbook of Histology. (Compiled and edited by
W. Bloom) Philadelphia, W.B. Saunders.
McClung, G.E., 1937, Microscopical Technique. New York, Paul B. Hoeber,
Inc.
Owen, R., 1868, Anatomy of Vertebrates. London.
Putter, A., 19^8, "Studien uber Physiologische Ahnlichkeit." Arch. _f. d.
ses. Physiol.. 172:396.
Quain, A., 1929, Ouain*s Anatomy. Vol. IV Part III. New York, Longmans,
Green and Co.
Retterer and Lelievre, "Structure du myocarde de quelques vertebries
inférieurs." Compt. Rend. Soc. Biol., T 66 et T 72.
Retzer, R., 1912, "The anatomy of the heart of the Indian elephant."
Anatomical Record. 6:75#
Schafer, E.S., 1929, Essentials of Histology. New York, Lea and Febiger.
Smith, A., 1912, Manual of Veterinary Physiology. New York, D. Appleton
and Company.
Sisson, S. and Grossman, J.D., 1938, The Anatomy of Domestic Animals.
Philadelphia, W.B. Saunders Company.
Thomas, I., Dry, W.B., Fredrich, A, and Williams, D., "Calcareous
diseases of the aortic valve." American Heart Journal. 17:138, 1939#
Vaughn, 1917, Strangeway* s Veterinary Anatomy. Chicago, Chicago
Medical Book Company.
White, P.D., and Kerr, W.V., 1917, "The heart of the sperm whale with
especial references to the A-V conduction system." Heart. 6:207-209.

Asset Metadata

Creator Perry, D. R. (author)

Core Title Some histological aspects of the Os Cordis in Bos taurus

Contributor Digitized by ProQuest (provenance)

Degree Master of Science

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag Biological Sciences,OAI-PMH Harvest

Format application/pdf (imt)

Language English

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c39-256548

Unique identifier UC11315712

Identifier EP67130.pdf (filename),usctheses-c39-256548 (legacy record id)

Legacy Identifier EP67130.pdf

Dmrecord 256548

Document Type Thesis

Format application/pdf (imt)

Rights Perry, D. R.

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA

Linked assets

University of Southern California Dissertations and Theses