T46 FIBULA. 



anterior margin, and gives attachment in front and be- 

 hind it to the anterior and posterior crucial ligaments. 

 Just below the articular surface the tibia presents on either 

 side a prominence; the inner is for the attachment of the 

 internal lateral ligament and tendon of the semi-membra- 

 nosus muscle ; the outer has an articular surface for the 

 head of the fibula. On the anterior part of the head of 

 the tibia a tubercle is seen for the insertion of the liga- 

 mentuni patellas. At its upper part there is a bursa. On 

 the inner side of this tubercle a concavity is seen for the 

 insertion of the tendons of the sartorius, gracilis, and semi- 

 tendinosus muscles. 



The inferior or larsal extremity of the tibia is much 

 smaller than the upper. Its lower surface is smooth, con- 

 cave and rather quadrilateral^ for articulating with the 

 upper surface of the astragalus. Internally there is a thick 

 vertical process, called the internal malleolus, which has its 

 outer surface smooth to articulate with the side of the 

 astragalus, and its inner rough for the attachment of the 

 internal lateral ligament. On its posterior ridge there is 

 a groove through which pass the tendons of the tibialis 

 posticus and flexor communis. On the external margin of 

 the lower extremity of the tibia there is a smooth triangu- 

 lar surface for articulation with the lower end of the fibula. 



The structure of the tibia, like that of all the long bones, 

 is compact in the body and cellular in the extremities. 



Its development is from three points one for the body, 

 and one for each extremity. Ossification is seen soon after 

 that of the femur. Soon after birth it takes place in the 

 head of the bone, and in the second year in the inferior ex- 

 tremity. The bone is complete about the twenty-fifth year. 



It is articulated with the femur, fibula, and astragalus. 



The fibula (Fig. 241) is a slender bone, situated upon the 

 outer side of the tibia, arid is nearly the same length with 

 that bone. It consists of a body and two extremities. 



The body is triangular and somewhat twisted. It has 

 three angles and three surfaces. The angles or ridges are 

 anterior, posterior and internal. The surfaces are external. 



