THE ANTERIOR EXTREMITIES. 79 



diately moved forward, and the false ribs more directly- 

 urged outward ; but both moving in both directions during 

 respiration. 



THE ANTERIOR EXTREMITIES. 



These extremities bear but little resemblance to the 

 human arm, particularly in those quadrupeds, as the horse, 

 who have a limb ending in a single hoof, toe, or phalange : 

 in those with several toes, the resemblance is much nearer, 

 till in the fore extremities of the ape they differ little but in 

 the thumb, which forms a bad antagonist to the fingers. It 

 appears a very wise provision of nature, to have given a 

 colt very long limbs at birth, that the form of parts might 

 not be afterwards much altered ; but, at the same time the 

 hinder ones are by much the longest ; because, were the fore 

 equal to the hind, the young animal would have been too 

 much elevated from the ground, and rendered incajDable of 

 grazing, or even of sucking conveniently. 



The shoulder-blade or scapula (Skel. Q) is a broad and 

 rather triangular bone, applied to the outside of the ribs, so 

 that its apex reaches downward between the first and second 

 ribs, and a portion of its base as far back as the seventh. 

 It is, therefore, situated obliquely, with its broadest extremity 

 above, and its narrowest extremity below. Its internal 

 surface is slightly hollowed and smooth ; its external is 

 divided into two unequal portions by a projecting ridge or 

 spine (Skel. h). Its anterior edge, as it continues down, 

 contracts inwards, and ends in a blunt rounded extremity 

 (Skel.f). Its superior surface is furnished with a consider- 

 able cartilage, covered with strong ligamentous fibres ; by 

 means of which the surface of muscular attachment is much 

 increased : yet with little addition to either weight or bulk, 

 and without the liability to fracture which would have been 

 incurred had the cartilage been bone. The posterior edge 

 of the scapula inclines inwards, and ends in its neck, the 

 bulging part immediately below the neck presenting a 

 shallow cup to receive the head of the arm bone {Skel. g). 

 The projecting ridge or spine divides the outer surface into 

 two unequal portions, of which the hindermost is the largest 

 {Skel. d and c). 



The arm hone or humerus {Skel. R) is strong, short, and 



