and presenting: 1, 

 excavated face ; 3, 



Fig. 44. 



77 



An 

 An 



TSE ANTEBIOB LIMBS. 



process — the olecranon — flattened on both sides, 

 external face, slightly convex; 2, An internal 

 anterior border, thin and sharp superiorly, 

 notched below to for mthe sigmoid cavity :^ an 

 articular surface concave from above down- 

 wards, rounded from one side to the other, 

 which corresponds with the humeral cavity, 

 and is surmounted by a salient prolongation 

 named the beak of the olecranon ; 4, A con- 

 cave and smooth posterior border; 5, The 

 summit, a kind of thick roughened tuberosity 



which terminates the olecranon above, and into 



which are inserted the extensor muscles of the 



fore-arm. 



At its inferior extremity, the ulna ends, 



towards the lower fourth of the principal por- 

 tion of the fore-arm,an an acute point, and 



sometimes by a small knob (capitulum uln'm). 



It is not rare to see it prolonged, especially 



in the Ass and Mule, to the inferior external 



tuberosity of the radius. This tuberosity then 



appears to belong to it, at least in part ; and 



all that portion which is situated behind its 



vertical groove might be justly considered as 



belonging to the ulna. 



Structure and development. — The ulna con- 

 tains much compact tissue, even in the region 



of the olecranon ; it is also very solid. It is 



an imperfect bone, developed from two centres 



of ossification only, one of these being for the 



apex of the olecranon. 



rOEE-FOOT OK HAND. 



The anterior foot, or hand, is the region 

 which presents the greatest differences when it 

 is inspected in the various individuals of the 

 animal series. Nevertheless, in all the mam- 

 malia the constitution of the hand is funda^ 

 mentally the same, and may be divided into - 

 three sections: the carpus, metacarpus, and 

 phalangeal region. , ,, j- o ^ ^^ ^i, 



Thi hand is fonned by five parallel or ''^l^^:^Z%Z. 



quasi-parallel rays that constitute tbe aigllS, ges -, 3, ScaphOides ; 4, Lunare ; 



each of which is effectively or virtually com- - ~ •- - ^ 



posed of two superposed carpal, a metacarpal, 

 and three phalangeal bones, forming altogether 

 the digit, properly so called. But this typical 

 composition, established through the labours 

 of MM. Joly and Lavocat, is rarely found to 



be realised in a complete manner. , . ^i , 



The following is what is presented m the hand of Man, who is the most 



' The greater sigrmid cavity of Man. 



EIGHT rOEE-rOOT OF A HOESI!. 



5, Cuneiform ; 6, Trapezium ;• 

 7, Magnum ; 8, Unciform ; 9, 

 Metacarpal ; 10, Small meta- 

 carpal; 11, Sesamoid bone; 12, 

 Suffraginis; 13, Coronary; 14, 

 Navicular; 15, Pedal; 16, Its 

 ala. 



