Section IV.
DByBLOPUINT OF THB CABTILAOBS. In the embryo and foetus these bodies, in consequence of the large quantity of water they contain, are soft, scurfy, and transparant, like jelly or glue. In the infant they are still nearly colourless, soft, and but slightly elastic. In the adult they gradually acquire consistence, whiteness, and opacity; it is also during this period of life that they are so eminently elastic. In old age they become more yellow and firm, and then lose a considerable portion of their flexibility and elasticity. The cartilages of (lie articulations arc very seldom ossified. Tlie costal cartilages, after the adult age, become homogeneous; and subsequently, osseous plates of unequal thickness in produced between them and their opaque perichondrium, and at length they are converted into bone. This change most commonly begins in the cartilaginous extremity of the first rib and afterward in the ribs below.
<Callout type="important" title="Important">Understanding cartilage development is crucial for managing joint injuries and degenerative conditions.</Callout> It does not, however, constantly occur, as these cartilages have been seen without any ossification in men of one hundred and thirty or one hundred and fifty years.
The tissues which have been described in the preceding chapters are composed of the cellular membrane and of its various modifications. But the parts which arc included in the system now to be considered, have so little external resemblance to the cellular substance that some excellent anatomists have denied the existence of any similarity between them. There is, however, little doubt that the albuminoid fibre of Chausier simply a condensed form of the common cellular fibre.
The term of fibrom synirm was applied by Bichat to a numerous class of organs that had previously been investigated only in an insulated and consequently imperfect manner. This word ought not, in strict language, to be confined exclusively to the system under consideration, because the fibrous structure is as perfectly developed in the muscles and nerves, as in the tendons and ligaments; but as the former are distinguished by other and more appropriate denominations, and especially tis., it would be difficult to suggest a name more expressive of the peculiar character of this tissue. I shall retain it for the sake of convenience.
<Callout type="risk" title="Risk">Failure to recognize cartilage changes can lead to misdiagnosis and improper treatment.</Callout> Although the configuration of these organs is various, yet two forms generally predominate. In the first, the length and breadth are nearly equal; the parts which possess this form are called membrana fibrosa, of which order nrv the periosteum, the dura mater, the capsular ligaments, &c. In the second, the length greatly exceeding the breadth, the fescicular form predominates; the parts which have this form, organa fibrosa fascicularto, consist of certain tendons and ligaments.
<Callout type="beginner" title="Beginner">For beginners, understanding the basic forms of fibrous organs is essential for grasping complex anatomical structures.</Callout> KolwithsUinding the different parts of this system, in which they are so much diffused in the animal frame, and apparently not independent of each other, they ore, with a few exceptions, strictly connected together, so as to constitute a continuous whole. Anatomists, even before the time of Galen, thought that the membranes of the body were continuous, and that they might be traced from the pericranium. A similar opinion was entertained by the Arabians, who appear to have regarded the membranes of the brain as the source of all the others. It is to these erroneous ideas that we owe the terms of dura mater and pia mater; these words are still employed in anatomical descriptions, although their original meaning has long ceased to be attached to them.
A careful examination of the connexions of the fibrous system will show that Bichat was correct when he pointed out the periosteum as its compositional centre, by which its different parts are joined together. In fact, if we except the perichondrium of the larynx and windpipe, and the fibrous membranes of some glandular bodies, it will be easy to demonstrate the above communication. Thus the cranial portion of the dura mater is continuous with the periosteum at the openings of the base of the skull; and the spinal process of the lumbar membrane, although not directly connected with the periosteum of the vertchne, is yet at the lower part of the caqui joined by some ligamentous filaments to the covering of the sacrum. The tunica sclerotica is limited with the dura mater, by means of the sheath which the latter affords to the optic nerve; and the fibrous membranes of the penis and clitoris interlace with the periosteum of the ossa ischia. Lastly, the fibrous sheaths of the tendons, the muscular aponeuroses or fascia:, the tendons and ligaments, are all in intimate connection with the periosteum, and, through its medium, to the bones.
<Callout type="gear" title="Gear">Understanding the structure of periosteum is crucial for proper bone care and injury management.</Callout> The different fibrous organs consist of an aggregation of distinct white or greyish fibres, which are nearly inelastic; they are also inseasible, and are distinguished by their power of resistance. In most parts of the body the fibres are disposed in a regular manner, And more or less, in a parallel direction; in other places, they cross and interlace with each other; and, in some instances, they form layers, which are superposed on each other so as to produce a most intricate fibrous web; this is the arrangement in the dura mater, in the irregular ligaments of the pelvis, in some of the aponeurosses, &c. The fibres of several tendons and ligaments are so small and so closely united together, that they cannot be perceived, although they become apparent by maceration. It has been already stated, that the ultimate fibres, which are extremely minute, are formed of the cellular substance very much condensed.
The different fibrous organs are surrounded by a quantity of cellular tissue; in those which possess distinct fasciculi, it forms sheaths around them, and even the fibres are enclosed by the cellular membrane, which becomes apparent by maceration. The blood-vessels of this system are not met with in the same quantity in all parts of it. The periosteum and the dura mater are very vascular; but the greater number of their vessels are provided for the supply of the bones; the fibrous tissue, in general, receives but few arteries and veins. Those which do exist may be displayed, after they have been filled with a fine injection, by drying the part and then plunging it in spirits of turpentine, id onia to render it transparent. Lymphatic vessels can only be perceived in a few of these organs; and as the periosteum and similar structures become very acutihlc in various diseases, it must be admitted that they have also communications with the nervous system.
The chemical composition resembles that of the cellular tissue. The basis of these organs appears to be coagulated albumen, united to different proportions of jelly and mucus; they contain no earth, and only a minute quantity of saline matter. By desiccation the water of the fibrous tissue is evaporated; and it then becomes hard, transparent, yellow, and fragile. It resists putrification for a very long time, but gradually it is rendered soft and flocculent on the surface; the fibres are separated, and at length it is reduced into a pulpy cellular substance. It is dissolwed by the mineral acids.
Key Takeaways
- Cartilage development stages vary from soft and transparent in embryos to firm and opaque in adults.
- Costal cartilages can ossify over time, but this is not universal.
- Fibrous organs are crucial for understanding joint health and injuries.
Practical Tips
- Understand the different forms of fibrous tissues to better manage joint injuries.
- Recognize the importance of periosteum in bone care and injury management.
- Be aware that cartilage changes can indicate degenerative conditions, such as arthritis.
Warnings & Risks
- Failure to recognize cartilage changes can lead to misdiagnosis and improper treatment.
- Ignoring the interconnected nature of fibrous tissues can result in incomplete healing or incorrect diagnoses.
Modern Application
While the specific terminology and methods have evolved, understanding the development and aging of cartilage remains crucial for modern survival preparedness. This knowledge helps in managing joint injuries, preventing degenerative conditions, and ensuring proper bone care. Modern techniques have improved imaging and treatment options but the fundamental principles remain relevant.
Frequently Asked Questions
Q: What are the stages of cartilage development according to this chapter?
According to the text, cartilage in embryos is soft, scurfy, and transparent like jelly or glue. In infants, it remains nearly colourless and slightly elastic. As adults, cartilage gradually acquires consistency, whiteness, and opacity, becoming more yellow and firm with age.
Q: How do costal cartilages typically develop over time?
The text states that costal cartilages become homogeneous after the adult age and can eventually ossify into osseous plates between them and their perichondrium, though this process does not always occur.
Q: What are some key differences between fibrous organs and cellular tissue?
Fibrous organs consist of distinct white or greyish fibres that are nearly inelastic and inseparable. They have a higher resistance compared to the cellular membrane, which is composed of more flexible elements.