CHAPTER VI 

 JOINTS 



EXAMINE carefully the joints of a rabbit. The most im- 

 portant joints to study are the shoulder and hip joints, and 

 the elbow and knee joints. The structure is essentially the 

 same in these animals as in man. The bones of the fore- 

 quarter of a lamb may be conveniently examined for the 

 shoulder joint. 



Immovable Joints. Unions of bones, where no move- 

 ment is allowed, are formed by the interlocking of the bones 

 of the skull with one another. 



Movable Joints. Movable joints are classified according 

 to the kind of movement they allow. ^ 



1. Gliding joint, allowing a small amount of movement. 



Example the joints between the vertebra?. 



2. Hinge joint, allowing backward and forward movement 



like a hinge. Examples elbow, knee, ankle. 

 v Hull and socket joint, allowing movement in all direc- 

 tions, and also rotation. Examples hip, shoulder. 

 4. Pivot joint, allowing movement of rotation only. 

 Examples the atlas on the axis, the radius on the 

 ulna. 



The ends of the bones which meet in a joint arc bound 

 together by ligaments of fibrous tissue, usually in the form of 

 strong bands, but one of the ligaments is thin and forms a bag 

 round the ends of the bones. This bag is quite closed by 

 being attached all round the bones a little distance from their 

 ends. It is called the capsule of the joint. The ends of 

 l lu- bom 'S which meet inside the capsule are tipped with a thin 



