410 THE TISSUES. 



1. The striated muscular fibres. 



2. Areolar tissue. 



3. Bloodvessels, lymphatics, and nerves. 



The last three will be described after the two preceding topics, 

 and the connection of the tendons with the bones and the muscular 

 fibres, have been disposed of. 



1. The striated muscular fibres, already described, are collected 

 together into bundles (fasciculi), each inclosed in a sheath of areo- 

 lar tissue (internal perimysium 1 ); these are collected together into 

 larger, and the latter into still larger, bundles secondary and ter- 

 tiary fasciculi; and finally the whole is inclosed in a sheath of 

 areolar tissue the external perimysium. These parts are seen in a 

 transverse section of a muscle, Fig. 263. The primary fasciculi are 



Fig. 263. 



Transverse section from the rectus capitis anticus major of man. a. External perimysium. 5. Peri- 

 mysium internum. c. Single fibre, and muscular fasciculi. Magnified 350 diameters. (K'Miker.) 



7^3 to 3 \ of an inch thick. The secondary and the tertiary vary 

 extremely in their dimensions. They are very evident to the un- 

 aided eye in the coarser muscles, especially the glutaeus maximus 

 and the deltoid. 



The direction of the fibres sometimes corresponds with that of 

 the tendon, and sometimes meets the latter at an acute angle (semi- 

 tendinosus, &c.). In the former case they are longer than in the 

 latter; sometimes, indeed, extending through the whole length of 

 the belly of the muscle as in the sartorius. 



2. The areolar tissue constituting the muscular sheaths (perimysia) 



1 From Trspt, around, and ,ui>c, a muscle. All the interfascicular areolar tissue 

 taken together is sometimes called the internal perimysium. 



