SKELETON OF LOWER LIMB. 177 



LESSON V, 



THE SKELETON OF THE LOWER LIMB.. 



1. THE skeleton of the lower limbs, like that of the upper, 

 is divisible into three categories : A, that of the hip ; B, that 

 of the leg ; and C, that of the foot. 



A. The skeleton of the hip, or the haunch-bone, is called 

 the os innominatum^ and there is one such on each side in 

 the adult man. 



B. The skeleton of the leg is subdivisible into 



(a) That of the thigh, which consists but of one bone, called 

 \hefemur (os femoris}. 



(b) That of the lower part of the leg, which consists of two 

 bones placed side by side. The larger of these is called the 

 tibia ; the other, much more slender and placed on the outer 

 side of the leg, is called \\\Q fibula, or peroneal 2 bone of the leg. 



C. The skeleton of the foot is subdivisible into three parts : 

 (a) that of the ankle, the tarsus ; 3 (b) that of the middle 

 part of the foot, the metatarsus ; and (c) that of the toes, or 

 digits composed of the phalanges. 



2. The OS INNOMINATUM is a very large bone, meeting 

 with its fellow of the other side in the mid-ventral line of the 

 body, and being strongly attached to the sacrum behind ; thus 

 forming, with the intervention of the last-named bone, a solid 

 bony girdle, supporting the trunk above, and being itself im- 

 pored on the limbs below-- the head of the thigh-bone fitting 

 into a socket on the outer side of the os innominatum. 



Each os innominatum is made up originally of three dis- 

 tinct bones, which become united when youth is merging into 

 manhood. These three bones are the ilium, the ischium, 

 and the pubis. 



1 From its not bearing any special resemblance to any one object, 



2 So called bec?use it clasps the larger bone of the leg, Trepoi/j, a clasp. 



3 From Tapa-og, a crate. 



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