188 



THE SKELETON 



The shaft or body [corpus] of the tibia, thick and prismatic above, becomes 

 thinner as it descends for about two-thirds of its length, and then gradually ex- 

 pands toward its lower extremitj'. It presents for examination three borders and 

 three surfaces. The anterior border is very prominent and known as the anterior 

 crest of the tibia. It commences above on the lateral edge of the tuberosity and 

 terminates below at the anterior margin of the medial malleolus. It runs a some- 

 what sinuous course, and gives attachment to the deep fascia of the leg. The 

 medial border extends from the back of the medial condyle to the posterior margin 

 of the medial malleolus, and affords attachment above, for about three inches, to 



Fig. 226. — The Tibia and Fibula at the Sixteenth Year. 

 The figure shows the relations of the epiphysial and capsular lines. 



Capsule 



Appears at birth; unites at twenty- 

 one : but union is sometimes delayed 

 to twenty-five 



Appears at the fourth year; unites at 

 twenty -four 



Appears at second year; unites at the 

 eighteenth year 



Capsule 



Appears at the second year; unites at 

 twenty 



tlic tibial (internal) lateral ligament of the knee-joint and in the middle third, to 

 the solevs. The interosseous crest or lateral border, thin and prominent, gives 

 attachment to the interosseous membrane. It commences in front of the fibular 

 facet, on the upper extremity, and toward its termination bifurcates to enclose a 

 triangular area for the attachment of the interosseous ligament uniting the lower 

 ends of the tibia and fibula. 



The medial surface is bounded by the medial margin and the anterior crest; it 

 is broad above, where it receives the insertions of the sartorius, (jracilis, and semi- 

 iendino.sus; convex and subcutaneous in the remainder of its extent. The lateral 

 surface lies between the crest of the; tibia and the interosseous crest. The upper 

 two-thirds presents a hollow for the origin of the tibialis anterior; the rest of the 



