OSTEOPOROSIS 57 



is its approach. A common early symptom is obscure 

 lameness. In regions where osteoporosis is of frequent 

 occurrence this disease should be suspected in every 

 instance in which an obscure lameness occurs, especially 

 if in addition to the lameness there is a history of capri- 

 cious appetite, lack of endurance, a tendency to perspire 

 easily and a tendency toward leanness. 



Another symptom that occurs quite early in the course 

 of this disease and which is quite reliable for purposes of 

 early diagnosis is ' ' cracking ' ' of the joints. This ' ' crack- 

 ing " is a sound that is very similar to a loud snapping of 

 the fingers. It is heard with the first movements that 

 the horse makes after he has been standing at rest for 

 some time, and also at times when a sudden, quick turn 

 is made by the animal. 



As the disease progresses the horse becomes unthrifty. 

 His frame assumes an abnormal setting, most noticeable 

 in a decrease in the obliquity of the pelvis. If the dis- 

 ease is active in the bones of the limbs, these seem to 

 increase in thickness, "buck-shins" develop, and the 

 shafts of all the long bones become more rounded and 

 increase in diameter. The bones involved in the disease 

 process are easily fractured, and it is not uncommon for 

 a fracture to occur while the animal is going through 

 ordinary or normal movements. In other cases tendons 

 pull loose from their insertions, ligaments are torn loose, 

 and similar complications are met with frequently. 



When the disease affects the bones of the skull we see 

 what is usually termed "big head." The facial bones 

 seem to puff out, giving the face a full appearance. As 

 a result of changes in the facial and nasal bones there 

 may be obstruction of the lachrymal duct ; narrowing of 

 the nares and involvement of the turbinates may produce 

 difficult breathing. The rami of the inferior maxilla are 

 rounded and thickened. The molars become loose, so 



