THE ANATOMY OF THE HORSE. la 



CHAPTER II. 



CONSIDERATION OF JOINTS, 



THE \-arious structures which enter into the formation of 

 joints are the extremities of bone, ligaments, cartilage, 

 and sometimes we have muscles which help to support 

 the joint. All articular joints are supplied with a synovial mem- 

 brane, which secretes the synovia or joint oil for lubricating- the joint. 



Cartilage, or what is familiarly called gristle, are of two 

 kinds, viz.: articular and fibrous. The fibrous is not of much 

 importance and does not need much consideration ; it is found in 

 various parts of the body. But the articular cartilage, which 

 covers over the ends of bones where they form a joint, is of more 

 importance. 



Ligaments are strong fibrous bands found principally around 

 joints. They are of two kinds, capsular and binding. A capsular 

 ligament is a thin membrane, attached around the end of each bone, 

 which helps to form a joint, and is, as it were, air-tight. The 

 uses of these ligaments are to keep the joint oil from escaping, 

 and partly helps to hold the bone together. On the inside lining 

 of this ligament we find the synovia membrane which secretes the 

 joint oil. Binding ligaments are generally found on each side of 

 of the joint, and are very strong bands of fibrous tissue. The uses 

 of these ligaments are to hold the bones of the joint firmly together. 



THE IMPORTANT POINTS OF JOINTS IN THE LEGS. 



Shoulder Joint. — This joint is formed by the shoulder blade, 

 or scapula, and humerus or shoulder bone. This is a ball-and- 

 socket joint, and has a strong capsular ligament, and is held to its 

 place also by several large muscles, the most important one 

 being the flexor brachii, which passes down over the shoulder 

 joint through a pulley-like process on the bone, and is held down by a 

 binding ligament which is supplied by a synovial membrane, or sack. 

 This is the seat of what is called shoulder joint lameness. The 

 motion of this joint is outwards or inwards, backwards or forwards. 



Elbow Joint is formed by the lower part of the humerus and 

 the upper part of the radius and ulna. It has a capsular ligament 

 and binding ligaments, one on the inside and one on the outside. 

 The action of this joint is just forwards and backwards, or flection 

 and extension, but has no side motion. 



