116 



malleolus, and indicates prodigious strength in the flexors of the toes and ad- 

 ductors of the foot. 



The distal articular surface of the tibia * presents the most singular modifica- 

 tions : it is divided into three compartments, which are well-defined, although 

 the synovial surface is uninterrupted. The external compartment, d, is semi- 

 elliptical, flat, nearly horizontal, inclining from without inwards and downwards : 

 it forms the lower surface of the outer distal protuberance of the bone, and rests 

 upon a corresponding surface, g, at the lower part of that excavation of the fibula, 

 which receives the said protuberance. The second compartment of the distal 

 articulation of the tibia is slightly concave, of a crescentic figure, with the horns 

 directed inwards and forwards : its plane is more nearly horizontal than the fibular 

 facet. The third compartment, e, is formed, as it were, by an excavation of the 

 anterior and inner side of the distal articular surface, causing the concavity of 

 the preceding crescentic surface, and the wide and deep semicircular notch which 

 characterizes the fore-part of the distal end of the tibia. The third and cres- 

 centic compartments of the distal articulation are exclusively articulated with the 

 astragalus, the singular form of which they sufiiciently indicate. 



Fibula f. — This is a detached strong subprismatic bone, enlarged at both ex- 

 tremities. The proximal end is obliquelj'' truncated, and capped by the flat cir- 

 cular surface (/), which underprops the horizontal articular plate extended from 

 the outer and posterior angle of the head of the tibia. A rough and slightly 

 compressed ridge extends downwards for about two inches from the outer side 

 of the proximal end ; below this the outer side of the fibula is impressed by a 

 rather oblique, smooth, shallow concavity : a ridge formed by the meeting of the 

 anterior and posterior surfaces of the bone is then continued along the rest of 

 the outer margin to its obtusely pointed distal end. The inner surface of the 

 distal expansion presents a concavity, two flat synovial articular surfaces, and 

 an intermediate rough ligamentous tract. The upper part of the concavitv is 

 very irregular; its lower part is formed by a flat obUque articular surface {g). 

 When the outer prominence of the distal end of the tibia is therein impacted, as 

 it was in its natural connections, the small outer compartment of the distal arti- 

 cular surface rests on the above-described articulation of the fibula. A narrow, 

 shghtly concave, transverse tract divides the upper from the lower articular sur- 



* Plate XX. fig. 4. f Plate XX. fig. 1, in conjunction with the tibia, and fig. 5. 



