2'24 FIBROUS TISSUE. 



aponeurosis, and from fastening the tendons in their grooves 

 in the form of their theca's or sheaths. The term fibrous was 

 applied to it by Bichat, (though its elements are dissimilar to 

 muscular fibre,) in consequence of its performing the office of 

 bands or chords, and being composed essentially of firm in- 

 elastic threads, or albuminous fibres. These fibres crossing 

 each other in various directions and woven densely together, 

 with some intervening cellular tissue, form the aponeuroses, 

 fascia?, sheaths, articular capsules, periosteum, dura mater, 

 and tunica albuginea ; arranged longitudinally, they form the 

 tendons of the muscles and the straight ligaments of the joints. 

 The tendons, by a little dissection, may be spread out into a 

 membrane, and in some parts of the body we see them naturally 

 unfolding themselves to form an aponeurosis. 

 Between all these different parts there is more or less con- 

 nexion. The tendons are inserted upon the bones only through 

 the intermedium of the periosteum, by which the bones are 

 covered. The aponeuroses are connected with the periosteum 

 by the fasciae which they send down between the muscles. 

 The ligaments and periosteum are directly continuous, and 

 the dura mater, as it sends out processes around the nerves, 

 becomes continuous with the periosteum that lines the foramina 

 of the bones, through which the nerves pass. Bichat, con- 

 sidered the periosteum the source and centre of this system ; 

 Bonn, of Amsterdam, as well as Clarus, believed the aponeu- 

 roses investing the limbs to be the centre ; an opinion more 

 venerable than either of these, that of the Arabian anatomists, 

 fixed it in the dura mater. But, in truth there is no proper 

 centre. In many parts, there is a fibrous tissue isolated from 

 the rest, as the investing coat of the spleen and kidneys, and 

 the fibrous portion of the pericardium. 



The fibrous tissue in all parts of the body is continuous, at 

 its surfaces and margins, with the common cellular tissue, and 

 in many parts we find it, especially in the aponeuroses and 

 fasciae, degenerating insensibly into it. There appears in fact 

 to be a close relationship between these two tissues ; in its 

 development in the foetus, it first appears as a soft, flexible, 



