16 MANUAL FOR, STABLE SERGEANTS. 



THE ARTICULATIONS. 



12. An articulation (joint) is the union of two or more bones or 

 cartilages by strong fibrous bands called ligaments. 



Joints are of three types immovable, slightly movable, and freely 

 movable. 



(a) In movable joints the contact surfaces of the bones are covered 

 with a thin, smooth layer of articular cartilage, the latter being lubri- 

 cated with synovia or joint oil. 



13. Synovia is a thin oil-like fluid secreted by the synovial 

 membrane. It is confined within and protected by the joint capsule, 

 which completely surrounds the joint. 



14. Ligaments, with the exception of the ligamentum nuchae 

 (neck ligament), are composed of inelastic white fibrous tissue which 

 bind the bones together. 



15. Ligaments which hold the bones in position are known as 

 binding ligaments. They are placed just outside the joint capsule 

 with which they are closely related. 



16. The suspensory ligament (figs. 5, 6, 7) is a long, wide band 

 of white fibrous tissue, originating on the back part of the lower bones 

 of the knee (hock bones in the hind leg) and the upper end of the 

 cannon bone. It then passes downward between the splint bones 

 and divides near the lower end of the cannon into two branches, 

 which are attached one to each sesamoid bone. From these bones the 

 branches pass downward and forward, one on the inner and one on 

 the outer side of the long pastern bone, to become attached to the 

 tendon of the muscle which extends the foot. Its function is to 

 brace the fetlock joint and support a large portion of the body weight. 



17. The ligamentum nuchae (neck ligament) is composed of 

 yellow elastic tissue, and extends from the withers forward, above 

 the cervical vertebrae, to become attached to the top of the skull. 

 It supports the head and neck. 



18. The plantar ligament is located on the outer posterior 

 border of the hock. It is one of the important binding ligaments of 

 the hock joint. 



19. The joints of the fore limb, named from above downward, 

 are the shoulder joint, formed by the scapula and humerus; the elbow 

 joint, formed by the humerus, radius, and ulna; the carpal (knee) 

 joint, formed by the radius, the bones of the carpus, and the large 

 and the two small metacarpal bones; the fetlock joint, formed by the 

 large metacarpal bone, the proximal sesamoids, and the first phalanx; 

 the pastern joint, formed by the first and second phalanges; and the 



