CHAPTER XV. 



MUSCULAR AND SKELETAL STRUCTURES. 



IN a logical analysis of the systems of the body, the motor 

 structures (voluntary) and the framework of the body deserve 

 equal and coordinate rank and consideration with the other 

 systems. The elemental tissues which make up the greatest 

 part of the muscular and skeletal structures have, however, 

 been already described (Chapter IV.), so that only a few fur- 

 ther points need attention. 



The voluntary muscles are made up of striated muscle-cells 

 or fibers, united by sustentacular connective tissue into fas- 

 ciculi, and these again into entire muscles. They are richly 

 supplied with capillaries. That portion of the sustentacular 

 tissue enveloping the entire muscle is called the epimysium ; 

 that investing the several fasciculi is the per imy slum ; the deli- 

 cate connective tissue within the fasciculi, among the indi- 

 vidual muscle-cells, is the endomysium. 



Tendons consist of white connective-tissue fibres cemented 

 together in parallel non-vascular dense bundles ; these are 

 bound together into entire tendons by trabeculse and sheaths 

 of sustentacular tissue, which contains the vascular supply. 

 In rows between the white fibres are the tendon-cells, special- 

 ized connective-tissue cells ; they send flat lamellar projections 

 between adjacent fibres, thus having a rectangular appearance 

 from the side, stellate in cross-section. The nuclei of adjoin- 

 ing cells are often situated near each other, forming pairs. 

 The surface of tendons is often lined with endothelium. 



The connection between the tendons and the muscle-cells is 

 in general established by the fibres of the endomysium ; these 

 are united on the one hand to the sarcolemma at the extremi- 

 ties of the muscle-cells, and on the other are connected with 

 tendon-fibres. At the junction of muscles and tendons their 

 connective-tissue elements are continuous and merge into 

 each other. 



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