126 THE ABTICULATIONS. 



then they are simple membranes, binding together the different funicular 

 bands of a joint. 



The interosseous ligaments, less numerous than the preceding, are often 

 formed of interlacing fibres ; they are always funicular, a-nd iixed by their 

 extremities into excavations in the centre of articular surfaces. 



6. The yellow ligaments are all peripheral, funicular, or membranous, and 

 enjoy a marked degree of elasticity, which permits them mechanically to 

 bring back to their usual position the bony levers which have been momen- 

 tarily displaced. These ligaments, which are powerful auxiliaries to the 

 muscular forces, are destined to give equilibrium in a permanent manner to 

 the weight of certain parts of the body which incessantly tend to fall to the ' 

 ground. 



Stnoviau Capsules. — These are very thin membranes of a serous nature, 

 intended to secrete the synovia. They are composed of two layers : a deep, 

 formed by fasciculi of the connective tissue; the other, superficial, is of 

 an epithelial character. The first sometimes adheres intimately to the inner 

 face of the funicular or membranous ligaments of the articulation ; at other 

 times it is loosely attached to them by an abimdance of connective tissue. 

 The second layer is constituted by a single row of flattened polygonal cells. 



It is generally admitted that the synovial membranes comport themselves 

 like the other serous membranes, by forming sacs which are everywhere 

 closed. According to this admission, a synovial membrane, after covering 

 the internal face of the peripheral ligaments of a diarthrodial articulation, 

 ought to be prolonged on the free surface of the cartilages of incrustation, 

 and should give them their brilliancy and polish. But it is necessary to 

 state that this is a pure hypothesis, against which rises a multitude of care- 

 fully-observed facts. The discussion of these belongs to general anatomy, 

 but they will be referred to here as briefly as possible. 



1. If direct observation be consulted, it gives on this debated subject 

 the most precise information ; the cartilages are uncovered, and there is 

 no synovial membrane on their face. The anatomists who have mistaken for 

 this membrane the thin pellicle which it is possible to render evident on the 

 cartilages in obliquely cutting their substance and separating morsels by 

 tearing it off, were evidently deceived. This pellicle has nothing of a serous 

 nature in its texture ; it is not vascular, for it has never been possible to 

 inject vessels on the surface of cartilages, nor yet in their thickness ; it is 

 not covered by epithelium ; and submitted to microscopical examination, it 

 exhibits -all the characters of the amorphous matter of cartilage. It ou"ht, 

 then, to be considered as a cartilaginous pellicle, detached from the super- 

 ficial layers of the articular surface — a pellicle which it has always been 

 impossible to find on cartilages which are quite fresh ; and it has never 

 been possible to observe it without giving, by a preliminary desiccation, a 

 certain degree of tenacity to the cartilaginous substance about to be 

 examined. 



2. Pathological facts prove nothing in favour of the existence of a 

 synovial membrane on the cartUages. Hypertrophy of this pretended 

 membrane has never been witnessed ; the fungosities looked upon as a result of 

 this hypertrophy are derived from another source. It has been demonstrated 

 that they extend, in certain cases, from the articular margins of the cartila- 

 ginous surface, whence their successive invasions may often be followed. In 

 other cases, the vegetating membrane which constitutes them appears in the 

 centre of the articular surfaces, at points deprived of cartilage ; they after- 

 wards extend to a certain distance on the remaining cartilage. 



