TIBIA. 



245 



Fig. 177. Bones of the Right Leg. Posterior Surface. 



Art 



TIBIA 



part, where fracture most fre- 

 quently occurs ; it then enlarges 

 again towards its lower ex- 

 tremity. It presents for exami- 

 nation three surfaces and three 

 borders. 



The anterior border, the most 

 prominent of the three, is called 

 the crest of the tibia, or, in popu- 

 lar language, the shin; it com- 

 mences above at the tubercle, 

 and terminates below at the 

 anterior margin of the inner 

 malleolus. This border is very 

 prominent in the upper two- 

 thirds of its extent, smooth and 

 rounded below. It presents a 

 very flexuous course, being 

 curved outwards above, and 

 inwards below; it gives attach- 

 ment to the deep fascia of the 

 leg. 



The internal border is smooth 

 and rounded above and below, 

 but more prominent in the cen- 

 tre ; it commences at the back 

 part of the inner tuberosity, and 

 terminates at the posterior bor- 

 der of the internal malleolus; 

 its upper third gives attachment 

 to the internal lateral ligament 

 of the knee, and to some fibres 

 of the Popliteus muscle; its 

 middle third, to some fibres of 

 the Soleus and Flexor Longus 

 Digitorum muscles. 



The external border is thin 

 and prominent, especially its 

 central part, and gives attach- 

 ment to the interosseous mem- 

 brane ; it commences above in 

 front of the fibular articular 

 facet, and bifurcates below, to 

 form the boundaries of a tri- 

 angular rough surface, for the 

 attachment of the interosseous 

 ligament, connecting the tibia 

 and fibula. 



The internal surface is smooth, 

 convex, and broader above than 

 below; its upper third, directed 

 forwards and inwards, is cover- 

 ed by the aponeurosis derived 

 from the tendon of the Sarto- 

 rius, and by the tendons of the 



Gracilis and Semi-tendinosus, all of which are inserted nearly as far forwards as 

 the anterior border ; in the rest of its extent it is subcutaneous. 



