AND PHYSIOLOGY. 



63 



sudden bend inwards, forming the neck of the bone, the ter- 

 mination of which is hemispherical, in order to articulate with 

 the innominatum, forming the ball and socket joint. Its 

 lower extremity has two large condyles or processes, for the 

 purpose of giving attachments to the ligaments of the knee, 

 and articulating with the tibia. 



140. The Patella —Or Knee Pan is the Fig. 81. 

 largest sesamoid bone in the body. It arti- 

 culates with the femur, and lies imbedded in 

 the extensor tendon of the thigh. The chief 

 value of this bone is to give a change of 

 direction to the force of the muscles which 

 move the lower bones of this extremity we 

 are now describing. Patella in Latin signi- An AnteriorTie ^ of 

 fies a "plate," and hence the name of this the Patella. 1, 2, sur- 



_ . , , , . face for the Quadriceps 



bone, because 01 its rounded outline. 



Femoris Tendon. 3, 

 Lower Extremity and 



141. The Tibia. — That portion of the Point of origin of the 



. - , , , , . , Ligamentuin Patelke. 



lower extremity below the knee, which is 

 properly the leg, has two bones called crural for its frame- 

 work. The largest of these is the Tibia (Fig. 82, p. 64.) It 

 is somewhat triangular in its general outline, having its 

 upper extremity depressed in two places for the reception 

 of the condyles of the femur. Besides the femur above, 

 it articulates with the fibula and astragalus below. The 

 name tibia is given to the bone, since it resembles, though 

 remotely, the ancient Phrygian flute. 



142. The Fibula.— The Fibula is the other bone of the 

 leg, long and slender. It articulates at each end with the 

 tibia. The meaning of the Latin fibula, is a "pin," or 

 fastening of a clasp, owing to its slender form. The lower 

 extremity of this bone, and also that of the tibia, forms what 



140. Describe the Patella or Knee Pan. In what is it imbedded? 141. What is the 

 Leg? What are the two bones of it? Which is the largest and consequently most im- 

 portant one ? 142. Give the general description of the Fibula. What compose the ex- 

 ternal and internal Malleoli ? 



