Synovial membrane

“ The destruction of cartilage may be secondary to disease of the synovial membrane or of the subjacent bone. When the disease begins as a synovitis, the synovial membrane spreads over the articular surface, fuses with the cartilage and eats into it, causing defects or holes which are spoken of as ulcers. When the disease begins in the bone, the marrow is converted into granulation tissue, which eats into the cartilage and separates it from the bone. ”

“ It is more dangerous than the inflammation of the synovial membranes in the form of bladders or bags, because the fibrous sheath which surrounds the inflamed membrane, not being able to stretch and yield to the swelling, like the cellular texture which surrounds the synovial bags, produces real strangulations, which it is often necessary to remove. I do not know whether the synovial texture of the tendons is exposed to the slow and tubercular inflammations, common to the articular serous and synovial systems. ”

“ Synovitis.—When a joint has been injured, inflammation occurs in the damaged tissue; that is inevitable. But sometimes the attack of inflammation is so slight and transitory as to be scarcely noticeable. This is specially likely to occur if the joint-tissues were in a state of perfect nutrition at the time of the hurt. But if the individual or the joint were at that time in a state of imperfect nutrition, the effects are likely to be more serious. As a rule, it is the synovial membrane lining the fibrous capsule of the joint which first and chiefly suffers; the condition is termed synovitis. ”

“ A very delicate connective tissue, called the synovial membrane, lines the capsules of the joints, and covers the ligaments connected with them. It secretes the synovia, or joint oil, a thick and glairy fluid, like the white of a raw egg, which thoroughly lubricates the inner surfaces of the joints. Thus the friction and heat developed by movement are reduced, and every part of a joint is enabled to act smoothly. ”

“ Although wounds penetrating the larger joints are attended with danger, the synovial membranes are possessed of considerable powers of reparation, and often heal readily after severe injuries. An occasional result of inflammation is adhesion between the layers of the membrane, but this is by no means so frequent as in the serous tissues. The reparative power of cartilage is so low that the best termination that can be expected from the ordinary forms of ulceration, is union between the abraded surfaces. ”

“ Their (synovial) membrane differs from the synovial membrane of joints in not having so continuous or definite an endothelial lining; indeed, while some bursæ, such as that beneath the ligamentum patellæ, have a more or less regular lining of regular endothelium, others have only elongated connective cells forming an imperfect lamella, and there are all possible gradations met with between the regular saccular bursa, and a loose meshwork of areolar tissue of which the bursa is only a specialisa­tion. ”

“ In consequence of certain inflammations, this membrane acquires a thickness and opacity which enable us to distinguish it from all the neighbouring organs, from those even to which it adheres the most. 3d. The synovial bags are all as adherent as the articular synovial one, to the cartilages of their sheath and to this sheath itself; yet every one acknowledges their distinct existence. 4th. There are articulations with a fibrous capsule, in which the fibres are separated so as to leave a space between them through which the synovia would179 escape, if the synovial membrane did not line them. ”

“ The commonest type is a chronic synovitis or hydrops, in which the joint—very often the knee—becomes filled with a serous or sero-fibrinous exudate. There are no reactive changes in the synovial membrane, cellular tissue, or skin, nor is there any fever or disturbance of health. The movements are free except in so far as they are restricted by the amount of fluid in the joint. ”

“ Usually they are present in large numbers, but sometimes there is only one, and it may attain considerable dimensions. They are not peculiar to joints, for they are met with in tendon sheaths and bursae, and their origin from synovial membrane may be accepted as proved. They occur in tuberculosis, arthritis deformans, and in Charcot's disease, and their presence is almost invariably associated with an effusion of fluid into the joint. ”

“ If the distension persists, the ligaments become elongated and the joint unstable.
The common origin of bone, cartilage, periosteum, and synovial layer from one parent tissue of the embryo, accords with the readiness with which any one of these tissues may be converted into another under traumatic or pathological influences; and how in ligaments and in synovial membrane foci of hyaline cartilage may form and, after increasing in size, undergo ossification.
Joints derive an abundant blood supply through the articular arteries. ”

“ In the third, the fibrous tissue in the neighbourhood of a joint is primarily affected, the synovial membrane and cartilages not becoming involved till the disease is much advanced. It is not uncommon in the elbow of middle-aged persons who have been much exposed to the atmospherical vicissitudes, and is sometimes attributed to the effect of mercury or syphilis. ”

“ When this fluid is secreted in excessive quantities, it produces a disease known as "dropsy of the joints." There are numerous smaller sacs besides the synovial, called bursæ mucosæ, which in structure are analogous to them, and secrete a similar fluid. Some joints permit motion in every direction, as the shoulders, some in two directions only, as the elbows, while others do not admit of any movement. The bones, ligaments, cartilages, and synovial membrane, are supplied with nerves, arteries, and veins. ”

“ Bodies composed of Organised Connective Tissue.#--These are comparatively common in joints that are already the seat of some chronic disease, such as arthritis deformans, Charcot's arthropathy, or synovial tuberculosis. They take origin almost exclusively from an erratic overgrowth of the fringes of the synovial membrane, and may consist entirely of fat, the arborescent lipoma (Fig. 159) being the most pronounced example of this variety. ”

“ The extensor pedis is usually attacked by extension of the disease from a necrotic cartilage, or results from the infliction of a severe tread in a hind-foot. In this case the diseased structure has nothing between it and the articulation, the synovial membrane in one position actually lining its inner face. The result is that a condition of synovitis is easily set up, and the case aggravated by that and by arthritis.
With the flexor tendons attacked pain is always very great, and lameness is excessive. ”

“ This organization is cellular, as is proved by dissection, inflation and especially maceration. The sac which the ganglions form is evidently only a production of the cellular organ; now it is known that this sac exhales and contains a fluid similar to the synovia. Wherever the synovial membrane is free, it is attached externally to this organ and is confounded with it in so direct a manner, that by raising successively its different layers they are seen to be gradually condensed and finally united together to form it. So that in the serous membranes no fibre is visible. ”

“ The ankylosing type of chronic arthritis is fortunately much rarer than those described above, and is chiefly met with in the joints of the fingers and toes and in those of the vertebral column. The synovial membrane proliferates, grows over the cartilage, and replaces it, and when two such articular surfaces are in contact they tend to adhere, thus obliterating the joint, cavity, and resulting in fibrous or bony ankylosis. ”

“ In others, the joints, although stiff, can be moved but exhibit pronounced crackings. When there is much connective tissue formed in relation to the synovial membrane, the joint is swollen, and as the muscles waste above and below, the swelling is spindle-shaped. Subacute exacerbations occur from time to time, with fever and aggravation of the local symptoms and implication of other joints. After repeated recurrences, there is ankylosis with deformity, the patient becoming a helpless cripple. On account of the tendency to visceral complications, the tenure of life is uncertain. ”

“ When the disease is confined to the synovial membrane, its onset is insidious, there is little or no pain, and no interference with any movement except complete extension. The chief evidence of disease is a white swelling on either side of and above the olecranon, obscuring the bony landmarks. ”

“ The synovial membrane secretes a viscous fluid, which is called syn-o ́vi-a. This lubricating fluid of the joints enables the surfaces of the bones and tendons to move smoothly upon each other, thus diminishing the friction consequent on their action.
Observations. 1st. In this secretion is manifested the skill and omnipotence of the Great Architect; for no machine of human invention supplies to itself, by its own operations, the necessary lubricating fluid. But, in the animal frame, it is 50 supplied in proper quantities, and applied in the proper place, and at the proper time. ”

“ When the disease begins with swelling, which is of a chronic character, and produces but little inconvenience, and when the more urgent symptoms supervene after the swelling has continued for a considerable time, there is every reason to suppose that the disease has originated in the synovial membrane, or perhaps in the osseous cancelli, and this is generally met with in poorly fed and strumous subjects. ”

“ When, in spite of all the methods of treatment here described, the condition does not yield, very good results may be obtained by the aspiration of the fluid, and the injection of a few drams of a three per cent. or five per cent. solution of carbolic acid. This operation, though [Pg 88] simple, requires every aseptic precaution, and should never be performed in the presence of any acute symptoms.
For other phases of Synovitis see Arthritis.
ARTHRITIS
The structures of a joint are: bone, cartilage, ligaments, synovial membrane and, in some cases, fibrocartilage. ”

“ The serous membranes are peculiarly liable to be attacked by secondary inflammation; and, when affected, suppurate with the greatest readiness. They generally exhibit but a slight degree of vascularity, and sometimes scarcely appear more injected than in their natural condition. In the peritoneal cavity, large quantities of unorganised lymph are frequently poured out, mixed with turbid serum or pus. The synovial membranes of joints, when affected, appear to run directly into suppuration, and will become distended with pus in a very short space of [Pg 55] time. ”