TIBIA. 



43 



and of the adductor magnus/'" This last insertion occupies this 



inner lip in nearly its whole length, so also 



does the origin of the vastus internus. The Fig. 26. 



outer lip has inserted into it the gluteus maximus^'" _ 



and also gives origin to the vastus externus, and 



the short head of the biceps flexor cruris.^ 



PATELLA. 



The patella is the largest sesamoid bone in the 

 body, and commonly called the knee-pan. It is 

 flat and triangular ; thick and broad above, and 

 thin and pointed below. The anterior surface is 

 covered by integument ; the 'posterior is a smooth 

 articular surface divided by a ridge unequally — 

 the external portion is the larger and flatter, 

 adapted to a corresponding surface of the femur. 



The superior edge is thick, and has the tendon 

 of the rectus inserted into it. The inferior is 

 pointed, and to it is attached the ligament of the 

 patella. 



TIBIA. 



The tibia is longer and thicker than the fibula, 

 and placed on the inside of the leg, and commonly 

 called the shin-bone. The superior extremity, or 

 liead^ is large and thick, presenting an oval arti- 

 cular surface for the femur. This surface is 

 divided by a pyramidal eminence, the spinous 

 process^'^ into two, both of which are oval, but 

 the internal is longer and deeper ; to the base of 

 this spinous process are attached anteriorly and posteriorly the 

 crucial ligaments ; in a depression upon its summit is fastened the 

 posterior end of the external semilunar cartilage. (Fig. 26.) 



An enlargement upon either side of the head are called tuberosi- 

 ties or condyles ; upon the posterior part of the external condyle"^ is 

 a small articular face, looking downwards, for the head of the fibula ; 

 upon the posterior part of the internal condyle'' is a depression for 

 the insertion of the semi-membranosus tendon. 



Below the head, and in front, is a prominent Uiberclt^ for the in- 

 sertion of the ligament of the patella, and above it a smoothness 

 corresponding with its bursa ; below the head, and behind, is a tri- 

 angular surface, occupied by the poplita:;us muscle, limited by an 

 oblique ridge^ (Fig. 28), which gives origin to the soleus muscle. 



The body is prismatic. Its internal surface^ (Fig. 27) is smooth 

 and covered by the skin ; the external surface gives origin to the 



