OSTEOLOGY AND ARTHROLOGY 71 



figure, the number 100. A very simple arithmetical opera- 

 tion gives the proportion — 



— = , the quotient obtained furnishes the index. 



humerus 



The index is less than 100 if the forearm is shorter than 

 the bone of the arm. The index is more than 100 if, on the 

 contrary, the forearm is longer. 



In man, the radius is shorter than the humerus; indeed, 

 in adult individuals of the white race the average index is 74. 



In the bear, the length of the radius approaches closely 

 to that of the humerus ; tlie index is about 90. In the 

 skeleton of a bear in the anatomical museum of the Ecole 

 des Beaux-Arts, the humerus is 33 centimetres in length, 

 and the radius 30 centimetres. 



In the cat, the radius is very little shorter than the 

 humerus. In the dog they are equal. The antibrachial 

 index of the latter is, accordingly, 100. 



In the horse, the radius is longer than the humerus ; the 

 index is therefore above 100. Thus, in the skeleton of the 

 horse which we have in the museum of the Ecole des Beaux 

 Arts, the index is 113 — length of humerus, 29 centimetres; 

 length of radius, 33 centimetres. In other skeletons which 

 we have measured we found : in one, 108 — humerus, 34 

 centimetres ; radius, 37 centimetres ; in another, 116 — 

 humerus, 25 centimetres ; radius, 29 centimetres. 



The metacarpal bone undergoes, relatively to the humerus, 

 a proportional elongation, analogous to that of the forearm. 



In man, the length of the metacarpus is contained about 

 5^ times in that of the humerus ; in the bear, it is contained 

 4 times ; in the dog, 2} times ; in the horse, i^ times only. 



It is well known that the proportions vary according to 

 race, and that what we have here given are but the general 

 indications. 



The Articulations of the Anterior Limbs 



The knowledge of human arthrology which we presume 

 the reader to have previously acquired makes it unnecessary 

 for us to enter into numerous details regarding the configura- 



