io6 



Anatomy of Skeleton 



ends for articulation with their corresponding metacarpals : the first phalanges are 

 the only long bones in the body that possess such facets, so that any such bone must 

 be a first phalanx of either hand or foot (Fig. 82). 



The second phalanges all possess double facets on the proximal ends for articula- 

 tion with the two " condyles " that are on the distal ends of the first phalanges, and 

 the distal ends of the second phalanges are somewhat similarly furnished, so that the 

 proximal ends of the third phalanges are also doubly facetted ; but the last phalanges 

 have flat expansions at their ends that distinguish them at once this exj-*sion 

 supports the fibro-fatty pulp of the finger tip. The two phalanges of the thumb 



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anterior surface 



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FIG. 86. On the left, a left scaphoid : top figure, from the front ; lower figure, 

 dorsal view. On the right, left semilunar : upper figure, from behind 

 and internally ; lower figure, from above. 



resemble the first and third phalanges in the other digits : the terminal phalanx 

 probably is compounded of a true third and remnants of a second phalanx. 



SEPARATE BONES OF CARPUS. 



The separate bones of the carpus bear individually the general characters that 

 have already been indicated as resulting from the building up of the whole mass, but 

 it may be pointed out here that the effect of the carpal concavity in enlarging the 

 dorsal surface of the bones is more than neutralised in the three main bones of the 

 first row by the somewhat dorsal position of the upper articular surfaces that is 

 correlated with the forward position of the hand with reference to the plane of the 

 forearm. 



Scaphoid (Fig. 86). Upper radial facet convex : inner facet is crescentic for 

 semilunar, and below this a large concavity for head of os magnum. ^ small rough 

 area between radial and semilunar facets is for interosseous ligament connecting it 

 with semilunar. Lower surface rests on trapezium and trapezoid, and is divided into 



