CHAPTER II. 

 CONSIDERATION OF JOINTS. 



THE various structures which enter into the formation 

 of joints are the extremities of bone, ligaments, car- 

 tilage, and sometimes muscles which help to support 

 the joint. All articular joints are supplied with a 

 synovial membrane, which secretes the synovia Or joint oil 

 for lubricating the joint. 



1. Cartilage. Cartilage, or what is familiarly called 

 gristle, is 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. The 

 articular cartilage, which covers over the ends of bones where 

 they form a joint, is of more importance. 



2. Ligaments. — Ligaments are strong fibrous bands found 

 principally around joints. They are of two kinds, capsular 

 and binding. A capsular ligament is a thin membrane, at- 

 tached around the end of, each bone, which helps to form a 

 joint, and is, as it were, air-tight. These ligaments serve the 

 purpose of keeping the joint .oil from escaping and assist in 

 holding the bones together. The synovia membrane is situ- 

 ated on the inside lining of this ligament. It secretes the 

 joint oil. Binding ligaments are generally found on each 

 side of the joint and are very strong bands of fibrous tissue. 

 They serve the purpose of holding the bones of the joint 

 firmly together. 



There is a very important ligament called the ligamentum 

 nucha. It supports the head when the muscles are at rest 

 and extends from the pole of the head backward under the 

 mane and is here attached to the spine of the dorsal vertebrae 

 or, commonly called, the withers of the horse. This ligament 

 is chiefly made up of fibro elastic tissue, and will stretch 

 much the same as a piece of elastic. This ligament can be 

 plainly seen in plate L, although not specially marked. In 

 operating on a case of poll evil there is always a danger of 

 cutting it off unless the operator be careful. 



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