Cartilage Canals Research Articles

The role of cartilage canals in the ossification of the talus.

Interrupted serial sections of the foot region from 14 human fetuses, crown-rump (CR) lengths between 32 and 240 mm, were studied, using HE, PAS, Alcian blue, Gomori's trichrome and von Kossa stains. Cartilage canals carrying vascular connective tissue from the perichondrium entered the talus by 68-mm. The centre of ossification developed in the neck region of the talus cartilage by 240 mm CR length, but early stages of chondrocyte proliferation and hypertrophy were noted by 108-mm CR length. The latter is marked by 170 mm CR length. A number of cartilage canals were observed around the developing centre. Branches from these cartilage canals appeared to supply vascular osteogenic tissue to its marrow spaces.

Dyggve-Melchior-Clausen syndrome. A histochemical study of the growth plate.

The Dyggve-Melchior-Clausen syndrome is a rare inherited disorder in which a major feature, the skeletal dysplasia, is thought to result from a defect in endochondral ossification. To further characterize this disturbance, histochemical studies were performed on an iliac-crest biopsy specimen from a patient with disorder. The use of plastic embedding methods permitted previous observations, which were based on decalcified paraffin-embedded tissues, to be extended and a variety of new ones to be made. The resting cartilage matrix was very fibrous. In many areas it consisted of randomly oriented bundles of loosely woven fibers that stained as collagen. The chondrocytes in this region were excessively vacuolated and many contained cytoplasmic inclusions that stained non-specifically as protein. Cartilage canals were prominent in the resting cartilage. In many areas, clusters of degenerating chondrocytes and occasional vacuolar lesions replaced the columns of proliferating and maturing cells that normally occupy the growth-plate region. There was coarse and irregular calcification of these clusters at the chondro-osseous junction, and intracartilaginous ossification was also found. These observations further define the histological criteria for the diagnosis of this disorder and provide new insights into its pathogenesis.

The occurrence of cartilage canals in shark vertebrae

Cartilage canals were found in the vertebrae of 16 species of sharks from five families. The canals variously contain blood vessels, lymph-like material, clumps of immature chondrocytes, unidentified amorphous material, or appear empty. Of 10 species examined in the family Carcharhinidae, only the dogfish, Mustelus canis, was devoid of canals. No canals were seen in the two batoid fish examined. The presence of canals may depend on the phylogenetic position or the maximum size attained by the species.

Morphology of the perforating cartilage canals in the proximal tibial growth plate of the chick

Perforating canals arise exclusively from junctional canals just above the reserve zone and they do not branch after entering the proliferative zone. They are uniformly spaced and arranged in parallel array. The cartilage canals terminate near the beginning of the zone of hypertrophic cartilage cells. Vascular components within the perforating canals consist of a central arteriole surrounded by enlarged, interconnected capillaries which are individually in contact with the adjacent cartilage matrix. TEM shows that the capillary endothelium is extremely attenuated, possesses numerous fenestrations and lacks a continuous basement membrane. The central arteriole is enlarged through the midpart of the canal and then narrows to communicate with the capillaries near the bottom of the canal. The large capillaries ascend from their point of origin and recombine near the top of the growth plate to exit as a single venule. The vascular arrangement therefore describes a system in which the outgoing blood runs in close proximity, but counter to, the incoming blood. This vascular arrangement within the perforating cartilage canal would most likely allow the zone of maturing cartilage cells to receive the highest concentration of nutrients.

Cartilage canals in the human spheno-occipital synchondrosis during fetal life.

Spheno-occipital synchondroses were studied histologically in eight human fetuses ranging from 100 mm CRL to term. Cartilage canals were present in all seven specimens over 110 mm CRL. With age the canals grew longer and wider and the larger ones developed some branching. The histologic structure, external morphology and spatial arrangement of these cartilage canals were described. Some attributes of cartilage canals were reviewed from available data in the literature and their significance for the present findings discussed. It was suggested that the canals, containing blood vessels and connective tissue elements, actively invade the cartilage of the synchondrosis. It was suggested further that they probably serve as a source of nutrition or as an extension of the perichondrium (and a source of prospective chondroblasts) or both.

Cartilage canals, their morphology and distribution.

AbstractThe proximal humeral chondroepiphysis of newborn pups was shown to be well‐vascularized by a series of segmentally distributed cartilage canals which varied from short unbranched channels to channels which coursed half‐way across the epiphysis. Cartilage canals were observed to contain a muscular arteriole, venule, loose connective tissue and perivascular capillaries. The muscular arterioles originated from the dense perichondrial vascular network at regular intervals, coursed in the central portion of the cartilage canal, and terminated by dividing into a capillary glomerulus in the cartilaginous matrix.These glomeruli were observed to assume a wide variety of sizes and shapes reflecting the metabolic needs of the areas they served. The capillaries of the glomerulus recombined into a single venule which rejoined the perichondrium via the same channel as the parent arteriole. The loose connective tissue surrounding these vessels was rich in fibroblasts and macrophages and was continuous with that of the perichondrium.From the structural relationship of the cartilage canals and the articular surface, it was concluded that at birth the synovial fluid had little nutritional significance for the epiphysis, but with age the nutritional contribution from the synovial fluid became more important.The particular arrangement of the venule and the perivascular capillaries allowed for metabolic exchange the entire length of the canal. Structures which appeared to be unmyelinated nerves and structures which contained a flocculent material and resembled lymphatics were seen in the connective tissue of the cartilage canals.

Temporary lobulation in cartilagenous models of long bones.

AbstractVascular patterns and the vertical zones of maturing cartilage cells are arranged in geometric radiations. This lobular arrangement reflects a distribution of cells and matrix of differing maturity; those cells and matrix closest to the collagenous wall of the vascularized canal are maintained in an immature state longer than those located toward the periphery of the lobule. This configuration suggests a relationship between the oxygenation of cartilage, its maturity, and its ossification. Arteries in the cartilage canal frequently are destined to become the arteries located within themarrow cavity of mature bones.

The relationship of cartilage canals to the initial osteogenesis of secondary centers of ossification.

AbstractInitial osteogenesis of secondary centers of ossification in the humeral head of the dog was studied with serial sections, histochemistry, radiography and vascular injections. At birth this chondroepiphysis was found to be well vascularized by a network of cartilage canals. On the second day after birth the first morphological evidence of the secondary center of ossification was seen. This was in the form of multiple foci of calcification. Each focus of calcification occurred immediately adjacent to the glomerular end of a cartilage canal and not in an avascular matrix. The capillaries of the glomerulus were modified in the process and persisted as the blood supply to the secondary center of ossification. By four days of age the individual foci had coalesced into a single larger focus of calcification. This process of ossification was found to possess morphological similarities to that occurring at the metaphyseal side of the epiphyseal plate.

The prenatal development of the human femur.

AbstractThe study reported here is the result of a detailed investigation of the changes in shape of the femur with growth and torsion, the type, rate and character of ossification, and the onset, subsequent course, and general features of remodeling.Forty pairs of femurs, from a series of embryos and fetuses ranging from 26 to 342 mm in crown‐rump length, were measured, radiographed, and sectioned for microscopic study.A primary bony collar was present before the end of the embryonic period, and in a 27 mm embryo it extended for about one‐fifth of the length of the femur. Erosion of the collar was evident at 34 mm. and invasion and destruction of calcified cartilage were occurring by 37 mm. Cartilage canals first appeared in the proximal epiphysis at 57 mm and in the distal epiphysis at 61 mm.Along with the progression of endochondral ossification proximally and distally and the establishment of growth zones, periosteal bone formation also proceeded in both directions, and, until 275 mm, extended about 1 mm beyond the zones of cartilage destruction. After 275 mm, the extents of periosteal and endochondral ossification were the same and at term occupied almost four‐fifths of the length of the femur.Trabeculation of the bony collar was first noted at 37 mm. Fusion of endochondral trabeculae with the inner aspect of the periosteal shell began by 61 mm. A central marrow cavity free of trabeculae was present at 86 mm and thereafter. Evidence of reconstruction appeared in both proximal and distal ends by 92 mm, and was consistently present in both ends in all specimens of 111 mm and larger.

The prenatal development of the human humerus.

AbstractForty pairs of humeri, from a series of embryos and fetuses ranging from 26 to 342 mm in crown‐rump length, were measured, radiographed, and sectioned for microscopic study.A primary bony collar was present before the end of the embryonic period, and in a 27 mm embryo it extended for nearly one‐third of the length of the humerus. Erosion of the collar occurred at the end of the embryonic period. By about 37 mm, endochondral ossification began, and cartilage canals were invading the proximal epiphysis.As endochondral ossification proceeded proximally and distally and growth zones became established, periosteal bone formation also proceeded longitudinally and, until about 18 weeks, extended about one millimeter beyond the zone of cartilage destruction in the growth zones. Subsequently the extents of periosteal and endochondral ossification were the same and at term occupied 79% of the length of the humerus.Trabeculation of the bony collar began in the embryonic period. Fusion of endochondral trabeculae with the inner aspect of the periosteal shell began by 61 mm. A central marrow cavity free of trabeculae was consistently present after 86 mm. Evidence of reconstruction appeared in the proximal end by 73 mm and in the distal end by 113 mm, and was always present after 97 and 125 mm respectively.

The Prenatal Development of the Skeleton and Joints of the Human Foot

One hundred and eighty-four human embryos and foetuses were studied. They ranged from seven to 460 millimeters in length. The skeleton of the foot was blastemal by Stage 17, and the various elements began to chondrify between Stages 18 and 23, that is, from approximately five and a half to seven weeks after ovulation. Chondrification occurred in a definite sequence. Cartilage canals were first seen at forty-three millimeters; they were found in all skeletal elements, including sesamoids. Their first appearance occurred in a definite sequence. Ossification was first noted in the metatarsals and distal phalanges early in the fetal period, and later in the proximal and middle phalanges. Some middle phalanges had not begun to ossify at term. Periosteal ossification was first noted in the calcaneus at ninety-three millimeters, and endochondral ossification at 150 millimeters (about five months). Endochondral ossification was first noted in the talus at 253 millimeters (about eight months). In two specimens at term, endochondral ossification was beginning in the cuboid. Cartilaginous sesamoids were first noted at thirty millimeters; their distribution and frequeney during the fetal period roughly corresponded to those reported for the adult. Fusions were noted as follows: talocalcanean, calcaneonavicular, cuneometatarsal, and interphalangeal. Fusion of the middle and distal phalanges of the little toe was common. Accessory ossicles. that were noted included os paracuneiforme, os intermetatarsale, and a separate cartilage in the tendon of the tibialis posterior. Homogeneous interzones were present in the joints of the foot by Stages 20 to 21. Cavitation began in a few joints during the embryonic period, but the formation of three-layered interzones, followed by cavitation, began in most joints during the early fetal period. Capsules and ligaments were present as cellular condensations before cavities and, in sonme cases, before three-layered interzones appeared.

人胎児骨髄血管構造の研究

Ossification of the middle part of clavicle derived from the connective-tissue ossification, and in epiphysis the primitive bone marrow origiantes from mesenchymal tissue possessing blood vessels. As for the nutrient foramen, its site, the number, and the angle of penetration into bone wall are not so uniform as in the case of long bone. This seems to be due to the peculiar ossification of the clavicle. Nutrient artery and vein do not necessarily penetrate into the bone wall together and when the two are in company, the nutrient vein usually occupies the position superior to the artery, and often two or three veins are found. Furthermore, one to several auxiliary nutrient foramens can be observable. The manners of branching and distribution of main nutrient artery and vein are rather regular. On the fourth embryonal month the cartilage canals containing arteries and veins make their appearance on both epiphyses, and by the fifth embryonal month they are connected with the bone marrow of epiphysis.

THE EVOLUTION OF EPIPHYSES AND OF ENDOCHONDRAL BONE

Summary1. The most primitive type of epiphysial mechanism known is found in bony fishes, and from this type all others are easily derivable. The cartilaginous epiphyses contain a mass of undifferentiated cells, a growth zone of flattened cells, and a zone of hyper‐trophied cells derived from them. Endochondral bone and marrow are well developed. Temporary cessation of growth may occur with loss of differentiation in the growth zone and the formation of a closing plate of endochondral bone shutting off the marrow from the epiphysial cartilage.2. In some modern fishes, Chondrostei and Dipnoi, endochondral bone and marrow have been lost, in others a secondary centre of calcification may be found in the epiphysis, but these changes are peculiar specializations.3. In primitive tetrapods, including all typical early fossil forms and the living Crocodilia and Chelonia, the cells of the growth zone are arranged more or less regularly in columns, and the endochondral bone, guided by these columns, again has a regular arrangement.4. Of the modern amphibians the Urodela have lost the regular arrangement of the cells of the growth cartilage, and have reduced the amount of their endochondral bone, while the Anura have developed a peculiar match‐head type of epiphysis with a calcified secondary centre.5. In Sphenodon a large calcified secondary centre is developed between the articular cartilage and the growth cartilage. By separating these cartilages it allows each to adopt the most advantageous position, the one for the formation of the joint surface, and the other for directing the arrangement of the trabeculae of the endochondral bone.6. All other groups are specialized in one direction or another. Bony secondary centres which strengthen the epiphyses are found in typical Lacertilia except in some small forms which have lost them, in the tibia of Aves and in Mammalia. Cartilage canals, developed primarily for the nutrition of the cartilaginous epiphyses, are found in Varanidae, Aves and Eutheria, and possibly in Anura, while the Monotremata have a very peculiar cartilage canal system whose development is not yet understood. These features are the result of very detailed parallelisms in evolution.7. Intratendinous centres of ossification, formed by ossification of tendons where these are inserted into epiphysial cartilage, are distinguished structurally from typical epiphysial centres.