SECT. 8l.] 



MUSCULAR SYSTEM. 



147 



these stronger clastic fibres, which measure from 0-0005'" to o 001" 



in diameter, there are in most, perhaps in all tendons, other very 



fine fibrils of o'oooz'" and o"ooo4-'" 



in diameter, which connect the 



former in various ways ; so that, in 



every tendon, a real network of 



clastic tissue penetrates and entwines 



the bundles of connective tissue. 



In transverse sections, these fibrils 



may also be distinguished as fine 



dark points, or as fine lines radiating 



from larger spots (fig. 67); they are 



still more distinct in longitudinal 



sections, in which the fibrous system 



Fig. 68. 



in question can ge- 

 nerally be very well 







Tendon of the human tibialis posticus, mag 



nified 60 times, a. Secondary bundles; 6. 



larger elastic fibres ; c. interstitial connective 



tissue. The minute dark points represent 



perceived. Such Sec- the finest elastic fibres. 



tions show, also, that wherever the formative cells 

 of the fibres still possess a certain degree of inde- 

 pendence, beautiful elongated nuclei exist in them. 

 Besides these elastic fibres, the tendons contain, 

 in certain places, cartilage-cells (see below) ; also 

 ordinary fat-cells, especially in the less compact 

 tendons, as in the tendinous stripes of the inter- 

 costal muscles, triangularis sterni, masseter, etc. 



The transversely-banded appearance of the ten- 

 dons, which occasions their glistening aspect, de- 

 pends simply upon undulating flexures of their 

 fibrils, which run parallel to each other through 

 the whole bundle. This appearance vanishes, 

 when they are strongly stretched, and is only the 

 expression of their inherent elasticity which pre- 

 sents itself in the relaxed condition. 



§ 8 1. Connections of the Tendons with other 

 parts. — The tendons are connected, on the one 

 hand, with the muscles, and, on the other, with 

 , n. a Muscular fibre the various parts moved by the latter. Even with 

 eo$taiuintemus,yass- the naked eye, it may be seen that in the former 



mtinuously into . , ,, , , , , 



a tendinous bnudie b. -, connection, either the tendon and muscle are con- 



ified 350 times. . , . , , .,. , . ,, ' 



tmued into eacli other rectilmearly, without any 

 distinct line of demarcation (fig. 68), or the muscular fibres, with 



l 2 



