THE MUSCULAR SYSTEM 



213 



envelope, the perifascicular sheath or perimysium. From the latter 

 delicate strands of connective tissue pass into the fascicles between 

 the individual muscle fibres. This constitutes the intrafascicular 

 connective tissue or endomysium, which everywhere completely 

 separates the fibres from one another so that the sarcolemma of one 

 fibre never comes in contact with the sarcolemma of any other fibre. 

 It 'should be noted that these terms indicate merely location; cpi-, 

 peri-, and endo-mysium all 

 being connective tissue grad- 

 ing from coarse to fine, as it 

 passes from without inward. 

 The structure of the muscle 

 as an organ is thus seen to 

 conform to the structure of 

 other organs, in that it is sur- 

 rounded by a connective- 

 tissue capsule, which sends 

 septa into the organ, dividing 

 it into a number of compart- 

 ments and serving for the 

 support of the essential tissue 

 of the organ, the muscle fibres 

 or parenchyma. 



The structure of tendon 

 has been described (see page 



95)- 



Tendon sheaths and burses 



are similar in structure, con- 

 sisting of mixed white and elastic fibres. Their free surfaces are 

 usually lined by flattened connective tissue-cells. 



At the junction of muscle and tendon, the muscle fibre with 

 its sarcolemma ends in a rounded or blunt extremity (Fig. 65, p. 123). 

 Here the fibrils of the tendon fibres are in part cemented to the sar- 

 colemma, and in part are continuous with the fibres of the endo- and 

 peri-mysium. This has been for a long time the accepted idea 

 of the transition from muscle to tendon, and is perhaps more nearly 

 correct where the insertion is oblique. It has been more recently 

 proved, however, that for some muscles at least, and especially where 

 muscle and tendon join end to end a much more intimate union of 

 elements occurs. This is shown in Figs. 129 and 130 from Stohr. 



Fig. 12.S. — From a Longitudinal Section 

 througil Junction of Muscle and Tendon. 

 X150. (Bohm and Davidoff.) a, Tendon; b, 

 line of union showing increase in number of 

 muscle nuclei; c, muscle. 



