26 THE VETERINARY SCIENCE 



I. The Important Points of Joints in the Legs. 



3. Shoulder Joint. — This joint is formed by the lower 

 end of the shoulder blade, or scapula, and the upper end of the 

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

 and has a strong capsular ligament. It 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. It is held down 

 by a binding ligament which is supplied by a synovial mem- 

 brane, or sack. This is the seat of what is called shoulder 

 joint lameness. The motion of this joint is outward or 

 inward, backward or forward. 



4. The 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 only for- 

 ward and backward, or flection and extension. It has no side 

 motion. 



5. Carpus, or Knee. — This is a very important joint, con- 

 structed of eight bones, having two rows, four in each, held 

 together by strong, short ligaments. Thus there are three 

 separate articular surfaces in this joint. The top side of the 

 upper row articulates with the bone of forearm ; this surface 

 gives the most motion to the knee. Another articulation 

 between the two rows of bones gives slight motion to the 

 knee, but not so much as the upper articular surface. Be- 

 tween the lower part of the lower row of bones and the upper 

 part of metacarpal, or shin bones, is another articular sur- 

 face which gives slight motion to the knee. This joint has 

 a large capsular ligament, and has binding ligaments inside 

 and outside. The action of this joint is the same as elbow 

 joint. 



6. Fetlock Joint. — This is formed above by the lower 

 part of the shin, or metacarpal bone, and below by the upper 

 part of the large pastern bone. At the back of this joint 

 there are two small bones called the sesamoid bones. This 

 joint has a capsular and two lateral binding ligaments. The 

 motion of this joint is backward and forward, same as knee. 



7. Pastern Joint. — This joint is situated just above the 

 hoof, and is formed by the lower end of the large pastern 

 bone and the upper end of the small pastern bone. It has a 



