Answer: A dislocation occurs when one of the bones which form a joint moves out of palace. The bones are usually separated by force; dislocation of the hip joint id the most common example following jumping or a road accident. In general, the thigh bone (femur) moves forward making the hind limb appear shorter. The lower jaw is also often dislocated and then the mouth will not close properly. In some cats a congenital defect of the stifle joint allows a small bone, the patella (keep-cap), to dislocate very easily without undue force. This condition is very common in the Devon Rex breed, causing an abnormal gait; in some case the stifle locks and the cat stretches its hind legs from time to time in an attempt to make the patella slip back into its correct position.
Many signs of dislocation are similar to those of fractures-pain, swelling, deformity and loss of function, but there are useful distinguishing features:
1 Pain and swelling is confined to the region of the joint.
2 Movement is more restricted then usual, not increased.
3 There is usually no grating sound.
4 Bones never penetrate the skin.
It can, however, be difficult to distinguish between a fracture and dislocation, particularly if the fracture is near a joint; occasionally they will occur together.
