BONES. 267 



broken through, so that the venous blood flowed freely in 

 spaces of the marrow, has not been supported by recent 

 investigations. The vein walls are exceedingly thin, but are 

 always present. 



The lymph-vessels form fine capillary networks in the 

 periosteum. The nerves are partly medullated and partly 

 non-medullated. They enter from the periosteum into the 

 Volkmann's and Haversiari canals and reach the bone-mar- 

 row. Some of these fibres end in Pacinian corpuscles in 

 the periosteum. 



(b) Joining together of Bones. 



The bones are joined together either immovably (synar- 

 throsis) or in such a way that they can move freely on one 

 another by joints (diarthrosis). 



The immovable combination is effected either by ligaments 

 (syndesmosis) or by cartilage (synchondrosis). The ligaments 

 may consist only of fibrous connective tissue and appear very 

 like tendons, or they may contain numerous elastic fibres 

 (ligamentum nuchse, ligamentum flava, etc.). The synchon- 

 drosis is formed usually by fibrous cartilage, which at the 

 border of the bone becomes hyaline. Special note must be 

 made of the intervertebral ligaments. These contain in their 

 interior a gelatinous mass (nucleus pulposus, gelatinous nu- 

 cleus), which is the softened remains of the chorda dorsalis. 

 Their periphery, however, consists of fibrous cartilage. 



In joints we must consider the articular ends of the bones, 

 the Libra glenoidalia, the menisci mterarticulares, and the joint 

 capsules. The articular ends of the bone consist of hyaline 

 cartilage, which is calcified on the side adjacent to the bone. 

 Often they are made up of fibrous cartilage (e. g., in the sterno- 

 clavicular and maxillary joints). The labra glenoidalia and 

 menisci interarticulares are fibrous cartilages. In the joint 

 capsules we distinguish an outer part (stratum fibrosum, capsula 

 fibrosa) and an inner part (stratum synoviale, capsula synovialis}. 

 The latter consists of loose connective tissue, which contains 

 fat cells, vessels, and nerves, and is clothed on its inner surface 



