Adventitious Growths are, on the whole, but rarely found in this system, though there are some fibrous structures which form an exception to the rule in the instance of particular new growths. Such is certainly the case with the dura mater in respect to sarcomatous and cancerous growths. And it must also be remembered, that in all cases in which fibrous membranes are implicated, it is extremely difficult to determine whether the new, and the degenerated growths which are imbedded in their tissue, were originally formed in them, or were developed, as undoubtedly may be proved to be far more frequently the fact, in the parenchymatous organs which those membranes enclose.

A. Cysts

a. Single cysts of small size are not uncommon in the structures belonging to the fibrous system. Their contents may be serous, or like synovia, viscid, or gum-like, or they may consist of cholesterine. Cysts with serous contents occur chiefly in tendons in and between aponeurotic expansions and fasciae, and in periosteum: those which contain cholesterine are most common in periosteum, where they are known by the name of encysted cholesteatoma.

B. Compound cystoid growths are very rare: I am acquainted with but one such case. It is that of an old and ill-preserved specimen of cystoid growth, some of which adhere to the periosteum, while others are contained in the muscles of the same lower extremity.

B. Fibroid Tissue

Fibroid Tissue is formed in fibrous structures, especially in ligaments and periosteum, when they have been swollen and thickened by chronic inflammation: it is also found in what are called fibrous tumors. These tumors are met with chiefly in periosteum, and in the dura mater: and they present the various characters of the soft, succulent, and delicately fibrillated tumor, filled with numerous elementary cells; of the spongy tumor composed of interwoven celled fibres, and of that which is dense and compact, and consists of well-formed fibrous bands. Their size is very uncertain, varying from that of a pea to that of a walnut or a fist; in a few cases, especially of genuine compact fibroid tumors, they are even as large as the head of a child.

C. Fibrous Structures

Fibrous Structures ossify in various ways. Not only are they liable to calcareous deposition, but when hypertrophied and indurated after inflammation, they sometimes have osteoid tissue developed in them. Sometimes it is formed in the substance of the fibrous structure, and resembles needles, cords, or plates, or is altogether shapeless; at other times it is a more or less complete incrustation upon its surface. Under such circumstances, a certain amount of vascularity is observed in the fibrous structure; it becomes of a brownish-red color, and remains, after the bony matter has been deposited, blackened with pigment, and uncommonly dry. Bony growths of this kind are formed for the most part in the fibrous capsule of the spleen, in the dura mater, and in the fasciculated articular ligaments. Of course similar productions are found in the fibroid tumors of fibrous organs.

But not only is osteoid tissue produced in fibrous organs; in some cases we find true bone in them. The exudations from periosteum and from the dura mater on the surface next the bone, become, when they ossify, normal bony tissue. They form broad, thin layers, or thicker, circumscribed plates and shapeless masses, and enter, for the most part at once, into organic connection with the bone beneath them. They are all included under the name of osteophyte and exostosis, whether occurring as a growth of bone in various tendons, as ossified callus in articular capsules after the occurrence of fractures within joints, or as ossification of fasciculated ligaments in cases of anchylosis, etc.

D. Tubercle

Tubercle is on the whole but rarely met with in fibrous organs: and when it does occur, it is almost only on the periosteum of spongy bones, and on the dura mater. In the usual mode of its origin, inflammation gives rise to a tubercular product, which is deposited in the tissue of the membrane, or on that surface of it which adjoins the bone; it degenerates into a mass of caseo-purulent matter, and being enclosed in a capsule of fibrous structure, which is infiltrated with lardaceo-gelatinous substance, it forms loose, pulpy swellings. By the progressive formation and degeneration of tubercles in the adjoining fibrous tissue it advances in the membrane, and to the bone; and frequently produces, especially in the spine, destructive ulceration of the periosteum and ligamentous apparatus along an extensive sinuous track, as well as caries of the bones.

Occasionally these sinuses close, and their contents become chalky. They are very commonly associated with tubercle in the cellular tissue, and in the lymphatic glands, and very often with tubercle in the lungs. This subject must be resumed in the chapter on the Diseases of Bone.

E. Sarcoma And Canceri

All fibrous structures may be destroyed by adjoining cancerous disease. In periosteum and the dura mater it occurs also as a primary disease, and from the former structure especially, it soon advances to the bone. Fibrous and medullary cancer are the kinds mostly observed in periosteum, but those which occur in the dura mater are very various, and differ remarkably in their elementary structure. Further remarks on this subject will be made in the chapters on the Diseases of the Bones, the Joints, and the Dura Mater.

Note

Some diseases have been described under the names of gum-mata, periostoses, and Cooper's cartilaginous and fungous exostoses; they will be found to be either a circumscribed inflammatory swelling and induration of the periosteum, or one of the adventitious growths which have been already described as occurring in it, or they will correspond with some of those to be hereafter brought forward amongst the diseases of Bone.