BONES 



39 



63. Bones of the Hind-Legs (Right and Left) 



Horse. Ox. 



Femur (thigh bone) 2 2 



Patella (stifle) 2 2 



Tibia (leg) 2 2 



Fibula (leg) 2 — 



Tarsus (hock) ... ... ... 6 pairs 5 pairs 



Astragalus, calcis, cuboid, sca-^i 



phoid, and two cuneiforms. / 



Large metatarsal .. . ... ... 2 2 



Small ,, ... ... ... 4 2 



64. The pastern bones correspond with those of the fore extremi- 

 ties both in name and number. The bones above the hock are the 

 same in the pig and dog ; the hock, however, consists of seven pairs 

 of bones in these animals, while each have twenty-nine pairs of 

 bones under the hock. The skeleton of the sheep is analogous to 

 that of the ox, both in number and names of bones (Plate VI.). 



65. Arthrology, or study of the joints. The various bones of 

 the body are held together by means of dense fibrous structures, 

 called ligaments, to form joints, which are of three classes. In 

 descriptive anatomy these are again subdivided, but the three 

 primary classes only will be dealt with — viz. : synarthrosis — 

 immovable, such as the union of the bones in the head ; amphi- 

 arthrosis — slightly movable, as between the bones of the vertebrae ; 

 diarthrosis — movable in any direction, as in the hip, shoulder, 

 knee, etc. 



66. Ligaments are dense, fibrous, amber - coloured, flexible 

 bands and capsular envelopes connecting ends of bones to form articu- 

 lations, and are composed mainly of white fibrous tissue. Some 

 ligaments, however, are mostly of yellow elastic tissue. The 

 ligamentum nuchas, which supports the head and neck, is 

 V-shaped, and extends from the top of the shoulder, or withers, to 

 the crown of the head, and consists of two layers or plates. Liga- 

 ments which hold the ends of bones together are termed capsular 



