162 STUDIES IN PHYSIOLOGY 



Bones of the Leg. In the upper part of the leg (see Fig. 

 64, A) is a single bone, the thigh bone or fe'mur. This cor- 

 responds in position to the humerus of the arm, but it is 

 longer and stouter than the latter ; in fact, it is the longest 

 bone in the body. The skeleton in the calf of the leg con- 

 sists of two bones, tib'i-a and fib'u-la, which have a position 

 similar to that of the radius and ulna. The tibia is on the 

 inner or great-toe side and is much larger than the slender 

 fibula. At the kneejoint one can feel a flat piece of bone, 

 more or less circular in outline, called the kneecap or pa-tel'la. 

 When one extends the knee and rests the heel on the floor, 

 the kneecap can be easily moved about over the kneejoint. 

 There are seven tar 'sal bones in the ankle, which like the 

 carpals have a somewhat cubical form. They are, however, 

 larger and less movable than the eight carpal bones of the 

 wrist. One end of the arch of the foot rests upon the heel 

 bone, the largest of the ankle bones. The arch is completed 

 by the other tarsal bones, and by five rather slender met-a- 

 tar'sals (Greek meta = beyond -f tarsds = ankle). The great 

 toe has two, and each of the other toes three phalanges, 

 making the same number of bones in the fingers and toes. 



2. THE SKELETON OF THE NECK AND TRUNK 



The Spinal Column. The erect position of the adult human 

 body is maintained by a column of bones called vertebrae 

 (Latin vertere = to turn, so called because these bones may 

 be turned more or less on each other). The spinal column 

 can be felt through the skin behind the neck and down the 

 middle of the back. 



In the neck region are seven bones called cer'vi-cal verte- 

 brae (Latin cervix = neck) ; twelve dor' sal vertebrae carry the 

 twelve pairs of ribs ; and in the loins are the five large lum'- 

 bar vertebrae (Latin lumbus = loin) . Below the lumbar 

 bones is a single bone called the sa'crum. When one exam- 

 ines it, however, four ridges and four pairs of holes are 



