Chap. V. The Anatomy of a HORSE. 6$ 



but efpecially to Beafts of Burden, being a Bar and Stay 

 to the whole Back. 



The Par qtiadratum, or fecond Palr^ fo called from 

 their Figure, being fquare when join'd together, tho' tri- 

 angular when feparate. They arife broad, thick, and 

 flefliy from the backward and upper Cavity of the Haunch- 

 bone, and from the inner and upper Side of the Os Sacrum, 

 and are inferted into all the tranfverfe Procefles of the 

 Vertebra of the Loins. Their Ufe is to bend the Racks 

 of the Loins with a right Motion forward or downward, 

 but when one only ads, it draws the Loins to one Side 

 fomewhat downwards. 



The third Pair, arifing from the Os Sacrum^ are there- 

 fore called Par facrum ; they fpring from that Part of 

 the faid Bone where the Spine is faften'd, ending in the 

 Spine of the loweft Vertebra of the Thorax ; but at the 

 lame time having in their Paflage feveral Infertions into 

 divers of the Spines and oblique Procefles of the Vertehrcs, 

 of the Loins. If thefe a6l feparately, they pull the Body 

 a little on one Side ; but when both ad together, they ex- 

 tend that Part of the Spine to which they are faften'd. 



The lall Pair, call'd Semifpitictufji^ arife with a nervous 

 Original from all the Spines or Ridges of the Os Sacrum 

 and Loins, and are inferted into the tranverfe Procefles of 

 the Loins, and fome of the lowermoft of the Chefl:. When 

 all thefe Mufcles of the Back and Loins work together, the 

 whole Back is extended ; but if the Mufcles of that Side 

 alone, the Body is then inclin'd to that Side*. 



The Anus hath three Mufcles, two callU I'he Anus three 

 the Levators, and one nam'd its Sphin5ier. Mufcles, 



The Sphin^er is feated at the Extremity j^^ Sthinaer 

 of the llreight Gut, encompafling it all 

 round like a Ring. It is attach'd to the lower Vertebra 

 of the Os Sacrum, compofed of circular Fibres, being of 

 ufe to contrad the Orifice of that Gut, as has been ob- 

 ferv'd in another Place. 



The two Levators, or Lifters up of the ^' tivo Lcua-^ 

 Fundament, are fmall, broad, and nervous, '^^-f* 

 arifing from the Ligament of the Hip-bones and Os Sa- 

 crum, from whence, pafling by the Sides of the Gut, 

 they adhere to it, and are inferted into the upper Part 

 of the Sphin6ler ; a Portion of them alfo growing to the 

 Root of the Yard, and in Mares to the Neck of the Ma- 

 trix. Their Ufe Is to allill the Mufcles of the lower BeHy 

 F in 



