SECT. 83.] 



MUSCULAR SYSTEM. 



'5 1 



of the peronceus longus turns round it, there is a layer of genuine 



cartilage of \'" to $'" thick. 



§ 83. Vessels of the Muscles and Accessory Organs. A. Blood- 

 vessels. — There is little peculiar in the ramification of the larger 

 vessels. The trunks passing into the muscles either obliquely or 

 transversely, and, running in the perimysium internum, divide, 

 at acute or obtuse angles, in an arborescent manner, so that all 

 parts of the muscles are supplied by them. The finest arteries 

 and veins usually run parallel Fig. 69. 



to the muscular fibres, and form 

 a capillary network between them, 

 which is so characteristic, that 

 when it has been once seen, it 

 can never be mistaken for any- 

 thing else. The meshes are rect- 



angular, with 



long 



sides which 



run parallel with the longitudinal 

 axis of the muscle ; so that the 

 plexus consists of two kinds of 

 vessels ; longitudinal, which lie in 

 the furrows between each pair of 

 muscular fibres, or in the irre- 

 gular spaces between several, as 

 can be especially well seen in 

 transverse sections of injected 

 muscles, and transverse ves- 

 sels, which, anastomosing in va- 

 rious ways with the former, form 

 a network around the muscular 

 fibres. Thus every individual 

 fibre might in a manner be said to lie in a plexus of capillaries, 

 and is richly supplied with blood on all sides. The capillaries of 

 the muscles belong to the finest in the human body, and have 

 often a smaller diameter than the human blood- corpuscles. In one 

 of HyrtVs preparations, they are 0"0025'" to o - oo3'" ; in the pec- 

 toralis major — filled with blood, o - oo2'" to 0'003'" — empty, 

 o*ooi6'" to 0'002'". 



The tendons belong to those parts of the body which are most 

 sparingly supplied with blood-vessels. The smaller tendons pre- 

 sent, in their interior, not a trace of blood-vessels, but are supplied 

 abundantly with wide-meshed networks of capillaries in the loose 



Capillary vessels of muscles, magnified 250 

 times, a. Artery. 6. Vein. c. Capillary 

 network. 



