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The repair of fractured membrane bones in the newly hatched chick.

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The Repair of Fractured Membrane Bones in the
Newly Hatched Chick
AND H. N. JACOBSON
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
B. K. HALL
ABSTRACT
Repair of a fractured membrane bone, the quadratojugal ( Q J ) ,
has been studied in the newly hatched chick. Complete open fractures never
united by bony fusion, even in birds maintained for six months post-fracture.
Extraperiosteal connective tissue invaded the fracture gap and formed thick
fibrous bundles which stabilised the fracture. Cartilage of two types formed on
these bones. One was derived from periosteal cells and the other from osteoblasts
or osteocytes. Considerably more cartilage formed in bones partially fractured
than in those completely fractured. The "periosteal" cartilage did not form if
the periosteum was removed at the time the bone was fractured. This was because, although the fibrous layer of the periosteum regenerated, the cambial
layer did not. Metaplastic cartilage did form in the absence of the periosteum.
Isolating fractured bones within polyethylene or glass tubes prevented accumulation of a blastema between the bony fragments. Cartilage did not form inside the tubes but did form where the ends of the tubes abutted onto the bones.
Large defects in the bones (4 mm gaps, 4 mm of bone in the place of the QJ)
healed via fibrous union with minimal osteogenesis and no chondrogenesis.
Severing M. depressor mandibulae at the time the bone was fractured inhibited
chondrogenesis, favoured osteogenesis and resulted in development of a pseudarthrosis.
The potential for differentiation of the cells of the QJ and the role of adjacent
tissues as they related to repair of the fracture was discussed, and the ability of
cells from membrane bones to become chondrogenic emphasized.
The repair of fractured bones has long
attracted the attention of clinicians, histologists, anatomists and orthopaedic surgeons. To the histologist the problems presented by the repair process are three-fold.
Firstly, to identify the types of tissues
which repair the fracture : whether bone,
cartilage, fibrous or connective tissue.
Secondly, to determine the source of the
cells which produce these tissues: whether
from the periosteum, endosteum, mature
bone, vascular system or extraskeletal connective tissue. Thirdly, to discover the microenvironmental factors responsible for
initiating a particular type of repair response : whether mechanical or electrical
factors, oxygen tension or degree of vascularity. Such studies have been reviewed on
a number of occasions during the past ten
years (Pritchard, '63, '65, '69; McLean and
Urist, '68; Hall, '70a; Ham and Harris, '71).
Almost all of this work on the repair of
ANAT. REC., 181: 55-70.
fractured bones has been carried out on
endochondral long bones. Comparatively
little attention has been paid to the repair
of membrane bones, although the repair of
fractures in the parietal bone of the rat
dermocranium has been extensively studied (Pritchard, '46; Girgis and Pritchard,
'58; Beresford, '69; Melcher, '69; Melcher
and Accursi, '71; Herold, Hurwitz and
Tadmor, '71; Herold et al., '71; Ritsila et
al., '72). Repair of the fractured 0s priapi
of the rat and of the rat and fish mandible
has also been investigated (Beresford, '70,
'72; Beasley, '72; Moss, '62). Repair of
fractures in avian membrane bones appears not to have been investigated.
The potential of membrane bones to
form cartilage during normal development
has been investigated and the studies
reviewed recently (Hall, '70a, '71). The
formation of such cartilage is of interest
Received Apr. 17, '74. Accepted July 3, '74.
55
56
B. K. HALL AND H. N . JACOBSON
because several authors in the past have
suggested that membrane bones would fail
to form cartilage when repairing a fracture,
arguing that as membrane bones do not go
through a cartilaginous stage during development, their cells would not have chondrogenic potential later in life. Cartilage
does form during repair of fractures in
mammalian membrane bones (Girgis and
Pritchard, ’58).
The purpose of the present study was
then to investigate repair of a membrane
bone, the quadratojugal ( Q J ) in the newlyhatched chick. We wished to determine
whether repair of the fracture would occur,
what type of tissue ( s ) would bridge the
fracture gap, the cellular origin of the
tissues formed, and the nature of the microenvironmental factors involved in the
reparative process.
leaving bone and periosteum intact on one
side (fig. lb). This was accomplished with
a fine dental burr mounted on a dental
drill. These animals were used to compare
the repair of a complete fracture of the
QJ with repair of a partial defect.
Another group of animals was used to
assess the cellular contribution from the
periosteum to the repair process. In the
control group the periosteum was removed
but the remainder of the bone was left
intact. In the experimental group the periostea were removed and the bones fractured. The periosteum was slit all around
the circumference of the QJ and then
peeled off. In those bones which were fractured care was taken to remove the periostea at least 1 cm on either side of the fracture (fig. l c ) .
The contribution to the repair process
from cells of the extraperiosteal connective
MATERIALS A N D METHODS
and vascular tissue was assessed in anOne to two week-old chicks (Gallus other experiment. The QJs were isolated
domesticus) were used as the experimental within glass or polyethylene tubes after
animals. They were fed Purina chick standard fractures had been created. The
starter and water ad libitum.
fracture occupied the centre of the tube
The quadratojugal ( Q J ) is a splint-like and the tube extended at least 1 cm on
bone lying immediately below the skin, on either side of the fracture (fig. Id). The
the lateral aspect of the head, ventral to the site of the fracture was thus effectively isoorbit. It articulates posteriorly with a con- lated from the cells outside the tube. As a
dyle on the quadrate and anteriorly has an control group, tubes through which holes
overlapping articulation with the jugal had been drilled were inserted over frac(figs. l a , 2). Its proximity to the skin, tured bones, thereby allowing ingrowth of
elongate form and lack of association with extraperiosteal cells to the fracture site.
major blood vessels or nerves made it ideal
Two experiments were carried out to
for experimental manipulation.
explore the healing of large defects in the
Chicks were operated on under ether QJ. In one, 4 mm, of the bone was reanaesthesia. In all animals the left QJ was moved. In the other almost all of the QJ
fractured or manipulated experimentally was removed, leaving only an anterior and
as described below. The right QJ served as a posterior stump of bone and a 2 to 3 cm
an internal control. To create standard gap between the stumps (fig. I f ) .
open fractures the skin and underlying
The role of growth pressures from other
loose connective tissue overlying the QJ surrounding tissues was assessed in two
were slit over a distance of 5 mm. This ex- ways. In one group the QJ was removed
posed the bone and a simple transverse cut and a 4 mm piece of bone placed back
with scissors gave a clean fracture (fig. into the resultant space. This graft therela). The wound in the skin was sealed fore lacked the normal connections to the
with spray-on antiseptic dressing and the muscles, ligaments and connective tissues
animals kept for up to six months, These (fig. l e ) . In another experiment the QJ
animals provided the base line for repair was severed, both anteriorly and posteriof a simple transverse fracture of the bone. orly, and left “free-floating’’ in situ. (fig.
A number of other manipulations were l g ) . These bones thus had two fractures to
carried out to answer specific questions repair, neither of which was subject to norrelating to the repair process. In one set of mal growth and muscle pressures.
animals the QJ was only partially cut,
To specifically study the role of muscle
57
REPAIR OF MEMBRANE BONE
e
C
d
h
w*.
Fig. 1 Membrane bones, black; endochondral bones, stippled; muscle, dashed. a. The
anatomy of the postero.lateral area of the chick skull. The splint-like quadratojugal ( Q J )
lies above the surangulzu and below the orbit and articulates posteriorly with the quadrate.
M. depressor mandibulae runs from the squamosal (top left) to the articular and M. adductor mandibulae externus runs from the squamosal to the surangular.
b-h The various experimental manipulations of the QJ are shown in b-h. b. The QJ
was partially sawn through with a dental drill. c. The QJ was factured and the periosteum
surrounding the fractuie removed. d. The QJ was fractured and a polyethylene or glass
tube placed over the fracture site. e. The QJ was removed and a 4 mm piece transplanted
back into the pocket. f. A large segment of the QJ was removed leaving a n anterior and a
posterior stump. g. The QJ was fractured both anteriorly and posteriorly and the shaft left
“free-floating” in situ. h. The QJ was fractured and M. depressor mandibulae sectioned
near its insertion onto the articular.
tension and normal bone movement in the
repair process the QJ was fractured and
the M. depressor mandibulae (M. dep.
mand.) sectioned at its insertion with the
articular process of Meckel’s cartilage (fig.
Ih). M. dep. mand. runs from the articular process of Meckel’s cartilage to the
squampsal (fig. l a ) and is the major muscle responsible for depressing the mandible. In the last experiment M. dep. mand.
was sectioned as above and a 4 mm piece
of bone removed from the QJ.
The experimental animals were killed at
the following time post-fracture: 1, 3, 5,
7, 9, 11, 14, 18 and 22 days. In addition
animals given standard fractures without
other experimental treatments were killed
at 30, 45, 60, 90, 120 and 180 days postfracture. A total of 93 fractured bones were
used for the histological study. These
58
B. K. HALL AND H. N. JACOBSON
bones were removed from the birds, fixed
in cold 80% ethanol, upgraded to absolute
ethanol, cleared in xylene, and embedded
in 54"m.p. Peel-a-way antistatic paraffin.
Decalcification of the specimens was usually avoided so that histochemical tests for
Ca++ and for alkaline phosphatase could
be applied to them. The following histological and histochemical tests were routinely used on serial sections cut at 10 p ;
Alcian Blue 8G, Chlorantine Fast Red 5B
and Haematoxylin (Lison, '54), to differentiate cartilage (bright blue) from bone
(bright red). Masson's trichrome (Pantin,
'60) was used as a general connective
tissue stain and to distinguish areas of collagen deposition. Ethanol-stable metachromasia after 0.01% toluidine blue (Ham
and Harris, '50) was used to visualise
sulphated acid mucopolysaccharides and
the early stages of chondrogenesis. Alkaline phosphatase was visualised with the
Gomori method and sites of calcification
with the von Kossa or alizarin Red S methods (Barka and Anderson, '65).
days were seen to have originated in the
cambial layer of the periosteum. Several
nodules of such cartilage, each associated
with spicules of bone, were found in each
specimen. In some specimens the osteocytes immediately adjacent to the fracture
surface had undergone metaplasia to
hypertrophic chondrocytes (fig. 5). They
were surrounded by prominent extralacunar capsules which stained with alcian
blue and which were metachromatic after
toluidine blue (indicative of the acid mucopolysaccharide nature of the capsules). No
extralacunar cartilage matrix was present.
Like the newly deposited osteoid at the cut
bone surface, the cartilage cells were alkaline phosphatase positive, whereas the
cartilage in the periosteum, which had not
undergone hypertrophy was alkaline phosphatase negative.
By eleven days collagen fibres from the
fibrous periosteum covered the cut ends of
the quadratojugal isolating it and its covering of periosteal cells from the now collagenous blastema between the fragments.
New bone formation was occurring only
RESULTS
slowly at the fracture site.
This same pattern of predominant colThe elongate form of the quadratojugal,
its overlapping articulation with the jugal lagenous repair was seen in the specimens
and the soft tissues separating the two examined from two to four weeks postbones from one another are shown in fig- fracture. Nodules of periosteal cartilage,
some quite large, were seen in many of the
ure 2.
specimens, and metaplastic cartilage was
Repair of complete fractures
seen within the bone itself (figs. 5, 6 ) . By
Three days post-fracture the gap be- six weeks thick fibrous tissue united the
tween the bone fragments was filled with two bone fragments. The only evidence of
connective tissue and fat cells derived from the metaplastic cartilage nodules was the
the extra-periosteal connective tissue (fig. cellular nature of the bone near the cut
3). This blastema was alkaline phosphatase surface and the occasional hypertrophic
negative and contained few collagen fibers. chondrocyte imbedded in the bone, alNo encapsulation of the blastema by the though at the edges of the fractured bones
fibrous periosteum had occurred. Cells cartilage was still proliferating in the camfrom the cambial layer of the periosteum bial layer of the periosteum.
had migrated over the stumps of the cut
At six months post-fracture (the latest
bones and had accumulated. No osteoid stage examined) bony fusion of the two
was seen at the cut bone surfaces.
fragments still had not occurred. Instead
By nine days post-fracture a prominent the interfragmental fibrous tissue had
mound-like connective tissue blastema formed thick fibre bundles over and beunited the fractured ends of the bone. The tween the bone pieces binding them toblastema was considerably more fibrous gether. The bone fragments were still quite
than at three days and was encapsulated far apart in many specimens (fig. 4).
Thus the normal repair process was
by fibres from the fibrous layer of the periosteum. Cartilage had differentiated among characterized by predominant connective
the cells which had accumulated at the cut tissue repair between the bone fragments,
surface of the bone and which at three some osteogenesis and the formation of
REPAIR OF MEMBRANE BONE
foci of cartilage which were subsequently
replaced by (converted jnto?) bone. The
major source of cells in the final repair of
the quadratojugal appeared to be from the
extraskeletal connective tissue which produced the connective tissue blastema, in
which the thick “ligaments” developed.
Bony fusion was not observed in any specimens although in some the bones were
close together and joined by fibrous tissue.
Repair of partial defects
Because the bones which were partially
cut were not completely separated from
one another and because the periosteum
was intact on one side the bony fragments
remained much closer together than did
the fragments in the cornpletely fractured
bones. Within two to three days the fibrous
periosteum had encapsulated the fracture
site, isolating it from the cells of the extraperiosteal connective tissue. Cells from the
cambial layer of the periosteum migrated
over the ends of the fragments, accumulated and initiated osteogenesis. Cartilage
was found among these periosteal cells
overlying the bone fragments several days
post-fracture and was present in much
greater amounts than after complete fracture of the bone. By five days post-fracture
the cartilage was being replaced by bone
through endochondral ossification. In most
specimens cartilage was not seen after 18
days post-fracture, its place having been
taken by bone (figs. 7, 8 ) . The bony fragments were approximating one another
but had not fused three weeks after the
fracture was made. The extensive fibrous
union seen in the completely fractured
bones was not seen in these partially cut
specimens.
These specimens were than characterized by rapid isolation of the fracture from
the surrounding connective tissue by encapsulation from the fitnous layer of the
periosteum; early and m,assive initiation of
chondrogenesis and rapid replacement of
the cartilage by endochandral bone.
The role of the periosteum
The cellular contribution from the periosteum to the reparative process was assessed by removing the periosteum, with
or without fracture of the quadratojugal
(fig. l c ) . Histological examination of un-
59
fractured bones immediately after stripping off the periosteum confirmed that all
of the outer fibrous layer and the majority
of the inner cambial layer had been removed. A few isolated cells on the periosteal surface were all that remained of the
cambial layer. The wound over the bone
rapidly healed so that several days after
the operation a unified epithelium covered
the injured connective tissue. Fibres produced by cells from the extraskeletal connective tissue rapidly encapsulated the
bones at their cut faces and renewed the
fibrous periosteum indicating that in normal development it is probably renewed
in a similar manner. The occasional
spindle-shaped cell between this layer and
the periosteal bone surface was the only
indication of a cambial periosteal layer,
indicating its failure to regenerate. No
chondrogenesis was seen in any specimens
from which the periosteum had been removed. Very little, if any, osteoid was deposited on the periosteal bone surface,
even several weeks after removing the
periosteum. Thus the fibrous layer of the
periosteum may be renewed from extraskeletal connective tissue cells but the cambial layer may not and cells from the
cambial layer are required before osteoid
formation and osteogenesis can recommence.
In those bones whose periostea were removed and which were also fractured the
fibrous layer of the periosteum was regenerated within several days. By seven days
post-fracture the fibrous periosteum had
encapsulated the stump of bone, isolating
the stumps from extraperiosteal cells of
the blastema which had formed between
the two cut faces. In some of the specimens examined at seven or 14 days postfracture, nodules of metaplastic cartilage
had formed near the cut surface of the
bone. These were always separated from
the periosteal surface by a layer of calcified bone and so were presumed not to
have arisen from cells at the surface. These
cells were hypertrophic, contained alkaline
phosphatase and were surrounded by capsules of uncalcified acid mucopolysaccharide material. Periosteal cartilage was
not seen in any of these specimens whose
periostea had been removed.
By twenty-one days post-fracture some
60
B. K. HALL AND H. N . JACOBSON
new bone was seen at the fracture site in
some specimens and the blastema had become collagenous.
Thus the essential difference between
these specimens and those repairing fractures in the presence of the periosteum was
the lack of accumulation of cells over the
cut surface of the bone and the absence of
periosteal cartilage, arguing that both the
cells and the cartilage were normally derived from the cambial layer of the periosteum, a layer which failed to regenerate
after removal of the periosteum. Metaplastic cartilage in the bone on the other hand
was unaffected by removal of the periosteum, arguing that i t is not derived from
cells of the cambial layer but from cells
within the bone.
The role of extraskeletal
Connective tissue
Bone were fractured in the standard
manner and then a glass or a polyethylene
tube placed over the two cut ends of the
bone sealing the fracture gap (fig. Id). A
connective tissue covering rapidly formed
over the tube and by seven days had become very fibrous. The cells immediately
adjacent to the tubes accumulated acid
mucopolysaccharide within two to three
days of implanting the tube and so provided “lubricating surface,” between the
tube and the adjacent connective tissue.
Cartilage was consistently found at the
ends of the tubes from five days onwards.
It was always associated with bone and
formed where the bone abutted onto the
end of the tube (fig. 9 ) . A gradation from
small prechondroblasts, to chondroblasts,
hypertrophic chondrocytes, and finally calcified cartilage against the tube was seen.
The bone inside the tube remained
viable. The osteoid and osteoblasts were
both positive for alkaline phosphatase.
Only a few collagen fibres were found in
the gap between the two bone pieces, indicating that this component of the blastema
was indeed primarily derived from extraskeletal connective tissue. No bony union
was seen and no cartilage was ever found
inside the tubes (fig. 10).
In a second series of experiments holes
were drilled into the tubes before placing
them over the fractured bones. The holes
rapidly became filled with connective tissue
and connective tissue blastema were produced between the bone fragments within
the tubes (fig. 11). The blastemata were
not collagenous but contained considerable
amounts of mucopolysaccharide. No cartilage formation or bony union was observed
in these specimens.
Healing large defects
A number of experiments were carried
out to test the healing of large defects in
the quadratojugal. In the first, a 4 mm gap
was made in the bone. Within three days
the large gap had been filled in with collagenous connective tissue, the fibres being
thickest in a central strand. Fibres from
the fibrous layer of the periosteum encapsulated each cut bone but not the blastema
so that no capsule united the two bone
fragment across the blastema. Little osteogenesis was initiated at the cut faces of the
quadratojugal and cartilage was not seen
in any of these specimens.
In the second experiment in this set the
quadratojugal was severed at its anterior
articulation with the jugal and at its posterior articulation with the quadrate and
removed. A 4 mm piece of bone was then
placed back into the connective tissue, well
away from each stump (fig. l e ) . These
pieces became encapsulated by fibrous connective tissue and the ends sealed off with
fibrous periostea. No cartilage was seen at
either cut end and minimal osteogenesis
was initiated.
In a third experiment approximately
90% of the quadratojugal was removed
and the repair of the stumps studied (fig.
I f ) . Again fibrous wound healing and
encapsulation of the bone predominated.
No cartilage was seen,
In a fourth experiment the QJ was cut
at each end but left free-floating in situ. A
connective tissue blastema joined each cut
end to its stump and became fibrous. The
blastema at the posterior end in all specimens produced cartilage (fig. 12). Bony
union of the body of the QJ with the
stumps was not observed.
The role of muscle tension
Two experiments were carried out to test
the role of muscle tension on the QJ and
its relationship to the types of tissues forming during repair of a standard fracture or
REPAIR OF MEMBRANE BONE
of a large ( 4 mm) defect. The M. depressor mandibulae (M.d.m.) was cut close to
its insertion onto Meckel’s cartilage, and
either a standard fracture or a 4 mm gap
made in the QJ (fig. l h ) .
The repair of the standard fractures
accompanied by severing M.d.m. differed
from repair of standard fractures alone in
three ways: ( 1 ) no periosteal cartilage was
found but small nodules of metaplastic
cartilage within the bone and close to the
fracture were produced; ( 2 ) the blastema
between the fragments was less collagenous; ( 3 ) more unca1c:ified osteoid was
deposited at the fracture face. These differences were observed by 14 days post-fracture. By 21 days the two bony fragments
had been united by fibrous tissue and an
articular cavity had formed (fig. 13). This
was an interesting finding for the tissue
forming the articular pads was fibrous and
it was derived from two sources. Against
the bone ends fibres froin the fibrous periosteum contributed to the articular tissue.
Toward the articular cavity the fibres
were derived from extraskeletal connective
tissue which had formed the blastema. The
cells immediately adjacent to the articular
cavity were imbedded jn acid mucopolysaccharide. Such a fibrous articular pad
was not seen in specimens whose M.d.m.
was intact or in those specimens where
M.d.m. was cut and where a 4 mm gap was
made in the QJ. In these latter specimens
fibrous tissue encapsulated the ends of the
bones but the bones never approximated
one another and fibrous union was not
seen. Cartilage was not seen in any specimens whose M.d.m. was severed, irrespective of the size of the defect in the QJ.
Thus the release of the fractured QJ
from the tension normally exerted by
M.d.m. was accompanied by failure of
chondrogenesis, and if the gap was small
by fibrous union and the formation of an
articulation between the two cut ends of
the bone.
DISCUSSION
In one sense the qu(adratojugal in the
newly hatched chick docs not heal an open
fracture, The wound between the cut ends
of the bone heals through infiltration of
connective tissue, which becomes fibrous
and ultimately ligameiitous, but this is
61
repair of the soft tissues, Several months
after fracturing, fibrous union of the bony
fragments occurs but bony fusion and
restoration of a single bony QJ is never
seen, despite the fact that both cartilage
and bone are produced at the fracture site.
The repair of the QJ was really effected
through repair of the adjacent connective
tissue which by six months post-fracture
had formed a tough ligamentous connection between the two bone fragments. The
faiIure of bony union may also be related to the small amount of cartilage
which forms at the fracture site in these
bones, In repair of endochondral bones a
large cartilaginous callus rapidly bridges
the defect as a short-term repair mechanism, Subsequently this callus is replaced
by bone. The short-term response in the
quadratojugal is formation of fibrous
tissue which by becoming ligamentous also
serves for long term repair.
The cells which contributed to the repair
which did occur came from a number of
sources. New bone was formed froin periosteal osteoblasts as occurs in repair of
fractured endochondral bone (Cooley and
Goss, ’58). These same cells from the cambial layer of the periosteum also produced
cartilage at the fractured ends of the bones.
This conclusion was based on the interpretation of static histological sections and on
the fact that when the periosteum was
removed, the cambial layer failed to regenerate and the cartilage failed to form. Autoradiographic evidence indicates that cartilage also arises from periosteal cells in
repair of fractured mouse and rat endochondral bones. (Tonna and Pentel, ’72;
Kernek and Wray, ’73).
The fact that, in the present study, such
cartilage failed to form at fracture sites
enclosed within glass or polyethylene
tubes, but did form where the end of the
tube rubbed against the bone or in partial
fractures; that no cartilage formed when
large defects were made in the bone or
when the M. depressor mandibulae was
cut, argues for, but does not prove, that
local mechanical stresses were responsible
for “inducing” such cartilage formation.
A number of authors (McLean and Urist,
’68; Herold, Hurwitz and Tadmor, ’71;
Herold et al., ’71) have maintained that
membrane bones, not having been through
62
B. K. HALL AND H. N. JACOBSON
a cartilaginous stage during their development, cannot form cartilage when repairing a fracture. However cartilage forms
during normal development on the articulating surfaces of avian and mammalian
membrane bones (Pritchard et al., '56;
Moss, '58; Hall, '68a,b, '70b); during repair
of skull bones in the rat (Pritchard, '46;
Eggers et al., '49; Girgis and Pritchard, '58;
Beresford, '69); during repair of the rat
dentary, penile bone (part of which develops intramembraneously ) and zygomatic
arch of the dog (Sarnat and Schour, '44;
Richman and Laskin, '64; Beresford, '70).
These and other secondary cartilages which
develop in the periosteum of membrane
bones have been discussed extensively
elsewhere (Beresford, '70; Hall, '70a).
The hypertrophic chondrocytes which
formed inside the bone adjacent to the fracture surface, which were separated from
the cambial layer of the periosteum by a
layer of bone, located in osseous rather
than cartilaginous matrix, formed after removal of the periosteum, and in which no
cell division or cytological sequence from
immature to hypertrophic chondrocytes
could be detected, were interpreted as
metaplastic chondrocytes which had arisen
from osteoblasts or osteocytes. Such examples of metaplasia of bone into cartilage
have been reviewed recently (Hall, '70a,
'72) and so will not be discussed extensively here. The fact that this cartilage was
not seen when large defects were made in
the bone, when M. depressor mandibulae
was cut, or when fractured quadratojugals
were enclosed within tubes argues, that
metaplastic cartilage, like the periosteal
cartilage, arises in response to local
mechanical stresses. Similar cartilage was
seen where ligaments or tendons inserted
onto membrane bones in newly hatched
chicks and was interpreted as a local response of osteoblasts to mechanical stress
(Hall, '68b).
The fact that quadratojugals isolated
within glass or polyethylene tubes produced minimal blastema uniting the bony
fragments, and that blastemata formed
after removal of the periosteum, indicated
that these cells were derived from the
extraskeletal connective tissue. These cells
made no contribution to the formation of
periosteal cartilage or to bone formation
although they may produce such tissues in
the repair of fractures of endochondral
bones (Murray, '54; McLean and Urist,
'68; Ham and Harris, '71; Kernek and
Wray, '73; Tonna and Pentel, '72; Pritchard, '69).
The experiments where the periostea
were removed indicated a dual origin for
the two layers of the periosteum. The outer
fibrous layer was replaced by cells from
the adjacent connective tissue and is presumed to be so replaced in normal development and growth. The inner cambial
layer failed to regenerate indicating that
it is normally not derived from the fibrous
layer or from extraperiosteal connective
tissue cells and that it apparently cannot
be regenerated by superficial periosteal
osteocytes.
Damage to the fibrous periosteum is sufficient to elicit an osteogenic response
from the remaining periosteal cells as
when the fibrous layer is stripped off the
mandible in the rat or off the tibia in the
rabbit (Beasley, '72; KCry, '72), or when
the periosteum is divided (Crilly, '72).
Application of periosteal grafts to bone
fractures, damage to a "distant" part of
the bone, or evaculation of the medullary
cavity all enhance periosteal osteogenesis
(Melcher, '69, '71; Melcher and Accursi,
'71, '72; Ritsila and Alhopuro, '72; Ritsila
et al., '72; Danckwardt-Lilliestrom et al.,
'72).
The creation of large defects in the QJ,
as when a 4 mm piece, or 90% of the QJ
was removed, or when a 4 mm piece was
grafted into the pocket made after removal
of the QJ, resulted in predominant fibrous
union with little osteogenesis and no chondrogenesis. Large gaps in fractured endochondral bones normally do not repair
unless bridged with bone or with other
tissue (Linghorne, '60; Banic, '65; Narang
et al., '71; Ham and Harris, '71). Apparently the rapid infiltration of the extraskeletal connective tissue into the gap between the fragments of the QJ and the
fact that this blastema became fibrous
within a few days post-fracture, provided
sufficient support and sufficiently delayed
cell accumulation and osteoblast formation
that osteogenesis could only proceed slowly.
A similar situation is seen in the repair of
REPAIR OF MEMBRANE BONE
the fractured penile bone in the rat (Beresford, ’70).
ACKNOWLEDGMENTS
Financial support from the National Research Council of Canadax (grant A5056 to
BKH) is gratefully acknowledged. HNJ
held a Dalhousie University Graduate
award during the tenure of the work. We
thank Dr. William A. Ber(3sford (University
of West Virginia) for his critical review of
the ms.
LITERATURE CITED
Banic, J. 1965 Experimen telle Untersuchunger
iiber die Knoch-entransplantation beim Hund.
Zentral Veterinarmed. Reilie, 12: 807-840.
Barka, T., and P. J. Anderson 1965 Histochemistry, Theory, Practice and Bibliography.
Harper and Row, New York.
Beasley, J. D., I11 1972 Induced bone formation in rat mandibles. Oral Surg., Oral Med.,
Oral Pathol., 32: 840-849.
Beresford, W. A. 1969 Vitamin A-deficiency
and cartilage in healing skull fractures of rats.
Experientia, 25: 383-384.
1970 Healing in the experimentally fractured 0 s priapi of the rat. Acta Orthop. Scand.,
41: 134-149.
1972 The influence of castration on
fracture repair in the perrile bone of the rat.
J. Anat., 112: 19-26.
Cooley, L. M., and R. J. Gosr, 1958 The effects
of transplantation and x-irradiation on the repair of fractured bone. Am. J. Anat., 102: 167181.
Crilly, R. G. 1972 Longitudinal overgrowth of
chicken radius. J. Anat., 1.12: 11-18.
Danckwardt-Lilliestrom, G . , S. Grevsten, H. Johansson and S. Olerud 1!372 Periosteal bone
formation on medullary evaculation: a bone
formation model. Upsala J. Med. Sci., 77:
57-61.
Eggers, G. W. N., T. 0. Shindler and C. M.
Pomerat 1949 The influence of the contactcompression factor on osteogenesis i n surgical
fractures. J. Bone Jt. Surg. 31A: 693-716.
Girgis, F. G., and J. J. Pritchard 1958 Experimental production of cartilage during the repair of fractures of the skull vault in rats.
J. Bone Joint Surg., 40B: 274-281.
Hall, B. K. 1968a In vitro studies on the mechanical evocation of adventitious cartilage in
the chick. J. Exp. Zool., 168: 283-306.
196813 The fate of adventitious and
embryonic articular cartilage in the skull of the
common fowl, Gullus domesticus. (Aves:
Phasianidae). Aust. J. Zool., 16: 795-806.
1970a Cellular differentiation in skeletal tissues. Biol. Rev. Camb. Phil. SOC.,45: 455484.
1970b Differentiation of cartilage and
bone from common germinal cells. 1. The role
of acid mucopolys&charide
and collagen.
J. EXP. ZOO^., 173: 383-394.
63
1971 Histogenesis and morphogenesis
of bone. Clin. Orthop. and rel. res., 74: 249268.
1972 Immobilisation and cartilage transformation into bone in the embryonic chick.
Anat. Rec., 173: 391-404.
Ham, A. W., and W. R. Harris 1950 Histological techniques for the study of bone and some
notes on the staining of cartilage in: Handbook of Microscopical Techniques, R. McC.
Jones, ed. Hoeber, New York, pp. 269-284.
1971 Repair and transplantation of
bone. In: “The Biochemistry and Physiology of
Bone.” G. H. Bourne, ed. 2nd Ed. Academic
Press, New York, 111: 338-400.
Herold, H. Z., A. Hurwitz and A. Tadmor 1971
The effect of growth hormone on the healing
of experimental bone defects. Acta Orthop.
Scand., 42: 377-384.
Herold, H. Z., A. Hurwitz, L. Lup. and A. Tadmor
1971 Influence of cartilage extracts on the
osteoblastic response in calvarial defects in
rats. Isr. J. Med. Sci., 7: 1164-1170.
Kernek, C. B., and J. B. Wray 1973 Cellular
proliferation in the formation of fracture callus
in the rat tibia. Clin. Orthop. and rel. res., 91:
197-209.
KCry, L. 1972 Effect of periosteal stripping and
incision of cortical bone on the longitudinal
growth of long bones: an experimental study.
Acta Chirurg. Acad. Sci. Hung., 13: 133-140.
Linghorne, W.J. 1960 The sequence of events
in osteogenesis as studied in polyethylene tubes.
Annals N. Y. Acad. Sci., 85: 445-460.
Lison, L. 1954 Alcian Blue 8G with chlorantine
fast red 5B: a technic for selective staining of
mucopolysaccharides. Stain. Technol., 29: 131138.
Melcher, A. H. 1969 Role of the periosteum fn
repair of wounds of the parietal bone of the
rat. Arch. Oral Biol., 14: 1101-1109.
1971 Wound healing in monkey (Mucaca irus) mandible: effect of elevating periosteum on formation of subperiosteal callus.
Arch. Oral Biol., 16: 461464.
Melcher, A. H., and G. E. Accursi 1971 Osteogenic capacity of periosteal and osteoperiosteal
flaps elevated from the parietal bone of the rat.
Arch, Oral Biol., 16: 573-580.
1972 Transmission of a n “osteogenic
message” through intact bone after wounding.
Anat. Rec., 173: 265-276.
Moss, M. L. 1958 Fusion of the frontal suture
in the rat. Am. J. Anat., 102: 141-166.
1962 Studies of the acellular bone of
teleost fish. 111. Response to fracture under
normal and acalcemic conditions. Acta. Anat.,
48: 46-60.
Murray, P. D. F. 1954 The fusion of parallel
long bones and the formation of secondary
cartilage. Aust. J. Zool., 2: 364-380.
McLean, F. C., and M. R. Urist 1968 Bone.
Fundamentals of the Physiology of the Skeletal
Tissue. 3rd ed. University of Chicago Press,
Chicago.
Narane. R., W. Lloyd and H. Wells 1971 Grafts
of decalcified dlogenic bone matrix promote
64
B. K. HALL AND H. N. JACOBSON
the healing of fibular fracture gaps in rats.
Clin. Orthop. and rel. res., 80: 174-180.
Pantin, C. F. A. 1960 Notes on Microscopial
Techniques for Zoologists. Cambridge University Press, Cambridge.
Pritchard, J. J. 1946 Repair of fractures of t h e
parietal bone in rats. J. Anat., 80: 55-60.
1963 Bone Healing. The Scientific
Bases of Medicine Annual Reviews., pp. 286301.
1965 Comparison of tendon and bone
repair. In “Studies in Physiology,” SpringerVerlag, Berlin. pp. 232-238.
1969 Bone. In “Tissue Repair.” R. H.
McMinn. Academic Press, New York, pp. 148168.
Pritchard, J. J., J. H. Scott and F. G. Girgis 1956
The structure and development of cranial and
facial sutures. J. Anat., 90: 73-86.
Richman, P. T., and D. M. Laskin 1964 The
healing of experimentally produced fractures of
the zygomatico-maxillary complex. Oral Surg.,
17: 701-711.
Ritsila, V. and S. Alhopuro 1972 Experimental
studies on the repair of bone defects and
tracheal cartilage defect with free periosteum.
Scand. J. Clin. Lab. Invest., 29, suppl., 122: 51.
Ritsila, V., Alhopuro, S. and A. Rintala 1972
Bone formation with free periosteum: an experimental study. Scand. J. Reconst. Surg., 6:
51-56.
Sarnat, B. G., and Schour 1944 Effect of experimental fracture of bone, dentin and enamel:
study of the mandible and incisor in the rat.
Arch. Surg., 49: 23-38.
Tonna, E. A,, and L. Pentel 1972 Chondrogenic
cell formation via osteogenic cell progeny transformation. Lab. Invest., 27: 418-426.
Note added in proof: Recently Craft et al. (’74),Plastic & Reconst. Surg., 53:
321-325, have shown that both cartilage and chondroid form in the fractured mandible and zygomatic arch of the rabbit, and that the cellular
layer of the periosteum was the origin of the cartilage.
Abbreviations
ABCR, Alcian Blue, Chlorantine Fast Red
PLATE 1
EXPLANATION OF FIGURES
2
A longitudinal section of the overlapping articulation (solid arrows)
of the splint-like quadratojugal (right) with the jugal (left). Note
the splint-like nature of the bones and the extraperiosteal f a t cells
(arrow). Gomori method for alkaline phosphatase (undecalcified).
x 560.
3
The quadratojugal five days post-fracture. Note the separation of the
bony fragments by a fibrous blastema ( b ) and the isolation of the
blastema from the connective tissue by re-establishment of the fibrous
periosteum (arrow). ABCR. x 140.
4
The quadratojugal six months post-fracture. Note the fibrous (ligamentous) tissue in and around the fracture gap ( f ) ; failure of the
bony fragments to approximate one another (c.f. fig. 3); little evidence
of remodelling of bone. Alizarin Red S. X 140.
5
Hypertrophic chondrocytes (arrows) within the quadrotojugal 9-days
post-fracture. The capsules stain for acid mycopolysaccharide, the
inter-capsular (osseous) matrix does not. ABCR. X 290.
REPAIR OF MEMBRANE BONE
B. K. Hall and H. N . Jacobson
PLATE 1
65
PLATE 2
EXPLANATION OF FIGURES
66
6
A quadratojugal 14 days post-fracture to show the relationship between the periosteal chondrogenesis ( c ) and the encapsulating periosteum (perichondrium, arrow). f , fibrous connective tissue of the
blastema. ABCR. x 147.
7
The repair site 14 days after a partial fracture. Note the approximation of the bony fragments to one another and the nodules of cartilage (arrow). cf. figure 3. ABCR. x 290.
8
The repair site 19 days after a partial fracture. Note the extensive
pads of cartilage ( c ) and the thick encapsulating fibrous periosteum
(arrow). cf. figure 7. ABCR. X 290.
9
A quadratojugal which was fractured and had a polyethlyene tube
placed over the fracture site 14 days previously. A prominent cartilaginous nodule has developed where the bone abuts onto the end
of the tube (T). ABCR. x 117.
REPAIR OF MEMBRANE BONE
B. K. Hall and H. N. Jacobson.
PLATE 2
67
PLATE 3
EXPLANATION OF FIGURES
10 The same specimen as in figure 9 to show the bony fragment within
the tube. Note the lack of remodelling of the bone ( b ) and the
absence of fibrous tissue in the blastema (bl). ABCR. x 147.
11 Cells and blood vessels from the extraperiosteal connective tissue
invading a hole in a polyethylene tube over a fractured quadratojugal: 14 days post-fracture. Toluidine Blue. X 147.
12 The posterior end of a “floating” quadratojugal 14 days after severing
it at each end. Note the remodelled contour of the bone fragment ( b ) ,
the proliferation of cartilage ( c ) and the re-establishment of the
fibrous periosteum ( p ) . ABCR. x 117.
13 The fibrous articular membrane ( f ) and articular cavity which has
developed from the blastemata at the fracture site in a specimen
whose M. depressor mandibulae was severed at the time the quadratojugal was fractured. ABCR. x 147.
68
REPAIR OF MEMBRANE BONE
B. K. Hall and H. N. Jacobson
PLATE 3
69
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