TEND ON-SHEA THS. 199 



Tendons and ligaments at their insertion into bones become 

 intimately blended with the periosteum, and their fibres often 

 meet the bony substance obliquely or perpendicularly. Some 

 of the fibres penetrate the bone for a short distance after the 

 manner of Sharpey's fibres, so that the osseous tissue and the 

 tendon-fibres dovetail into each other, affording a very firm 



FIG. 75. 



Cross-section of portion of tendon (Schafer). 



union. These fibrous insertions can be stripped from the 

 bone only with difficulty, more so than the periosteum else- 

 where, and the surface of the denuded bone at such points is 

 rough and uneven. 



Synovial membranes, allied to serous membranes, are thin 

 fibrous membranes more or less completely covered on their 

 free surface with flat connective-tissue or endothelium cells. 

 They form sheaths or sacs in connection with moving surfaces, 

 of three kinds articular, vaginal, and bursal. The arricular 

 synovial membranes inclose joints ; the vaginal form tendon- 

 sheaths ; the bursal line the bursse. They secrete, by a sort 

 of glandular action, a glairy fluid which lubricates the opposed 

 surfaces that move on each other. 



Tendon-sheaths : The tendons in some situations, in the 

 vicinity of joints, notably in the hand and foot, are sur- 



