106 



BONES OF THE LOWER LIMB. 



border, after projecting rather abruptly forwards, slopes downwards and 

 backwards ; its posterior border presents a shallow groove traversed by the 

 tendons of the peronei muscles ; while externally it is convex and subcu- 

 taneous, and a triangular subcutaneous surface is continued up from it for 

 an inch or two on the shaft. 



Fig. 98. 



Fig. 99. 

 5 



Fig. 98. RIGHT FIBULA PROM THE OUTSIDE AND 



BEFORE. 



1, shaft, outer and anterior surface, showing the 

 oblique grooves of the peronei muscles ; 2, head ; 3, its 

 projection, giving insertion to the tendon of the biceps 

 feraoris ; 4, malleolus externus or lower end, the figure 

 is placed opposite its anterior or oblique edge ; above this 

 is seen the triangular subcutaneous surface of the bone. 



Fig. 99. RIGHT FIBULA FROM THE INSIDE AND 

 BEHIND. | 



5, the oblique surface of articulation with the tibia 

 superiorly ; 6, points to the internal or interosseous 

 ridge ; 7, the triangular rough surface for the lower 

 interosseous ligament ; 8, the external malleolar surface 

 for articulation with the astragalus ; 9, groove behind 

 the malleolus externus for the tendons of the peronei 

 muscles. 



The shaft is irregularly three-sided and 

 twisted. One surface, from which the peronei 

 muscles take origin, looks forwards at the com- 

 mencement, then, turning outwards and back- 

 wards, is continued behind the subcutaneous 

 space of the lower end to the groove behind the 

 malleolus. Another surface, looking backwards 

 in the upper half of its extent, winds inwards 

 and terminates above the articular surface of 

 the malleolus; near its upper end this surface 

 is rough, giving attachment to the soleus 

 muscle, and in the rest of its extent it is occu- 

 pied by the flexor longus pollicis. The remain- 

 ing part of the surface of the bone, internal, 

 turns forwards inferiorly, and terminates on the 

 anterior margin of the malleolus : it is divided 

 by a longitudinal line, the interosseous ridge, 

 into a posterior and upper part, which gives 

 origin to the tibialis posticus, and an anterior 

 and lower part, from which arise the long ex- 

 tensors of the toes and the peroneus tertius, 

 the interosseous membrane being attached to 

 the line between these surfaces. About the 

 middle of the posterior surface is the medullary 

 foramen directed downwards into the bone. 



THE TARSUS. 



The tarsus is composed of seven bones, viz., the os calcis, astragalus, 

 cuboid, scaphoid, and three cuneiform. 



