CHAP. VII.] TENDONS. 163 



Each one of the elementary fibres now described may be properly 

 regarded as a distinct and perfect organ. In some of the smaller 

 forms of animal life, we have examples of a striped muscle consist- 

 ing of a single fibre ; and not only so, but this fibre reduced to 

 a single series of sarcous elements, or a fibrilla. But in all the 

 larger animals, and in the human body, with which we are specially 

 concerned, solitary fibres never occur : they are always aggregated 

 in parallel series of greater or smaller size, and associated with other 

 tissues, which minister to their nutrition, or to their mechanical 

 connexion either to one another or to neighbouring parts. Thus 

 the compound organs termed muscles are formed. 



In these, the angular figure of the fibres results from their contact. 

 The sets in which they are packed usually contain ten, twenty, 

 thirty, or more ; these again being united into larger sets, and so on, 

 so as to form the variously sized fasciculi and lacerti of Prochaska 

 and others, until the whole muscle is formed, consisting, it may be, 

 of very many thousands. Though the fibres of a small set are 

 always parallel, and the primary sets usually so, it often happens 

 that the larger sets are placed obliquely to one another, and there- 

 fore do not act in the same direction ; and, even when all are parallel 

 to one another, they are often oblique to the cord or tendon their 

 force acts upon. Such muscles are styled doubly or singly penni- 

 form, from their resemblance to the plume on a writing-quill. All 

 such arrangements, infinitely varied, are mechanical contrivances 

 by which symmetry of form, or extent of motion, is obtained at the 

 expense of power. 



White fibrous tissue reaching from the end of a muscular fibre 

 to some structure which is to serve as a fixed attachment for it, or 

 which it is intended to move, is called a tendon. The fibrous tissue 

 thus running from many contiguous fibres (as those of a whole 

 muscle) is usually united into a single tendon. This may be 

 lamellated, cordiform, &c., according to the arrangement of the 

 muscular fibres themselves (see p. 71) . 



Tendinous fibres are much less bulky than the muscular fibres of 

 which they are the prolongation; arid from this result many conse- 

 quences. Tendons are employed for symmetry, and where muscular 

 structure would be useless, from the mechanical impossibility of 

 more than a certain amount of motion in a part. Moreover, where 

 a muscle consisting of a large number of fibres has to be attached to 

 a large surface, the tendinous fibres are diffused ; but, if the same 

 muscular substance has to be fixed to a small point of bone, the 

 tendon must be collected into a cord. Now, it would be impossible 



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