738 FRACTURES OP THE PELVIS. 



depends on the amount of displacement and the nearness of the 

 fracture to the joint, prognosis should be preceded by rectal 

 examination. Prognosis is, however, generally doubtful, and is 

 the more unfavourable the more patent the deformity of the croup, 

 the greater the depression of the ilium, and the nearer the fracture 

 to the acetabulum. Marked atrophy of muscle is also an unfavourable 

 symptom. Stockfleth saw continuous lameness due to formation 

 near the joint of a large callus, which interfered with movement 

 of the upper trochanter. 



(3) Fractures of the acetabular branch of the os pubis and of the 

 ischial shaft are also grave. Union proceeds slowly, and often 

 remains incomplete, resulting in the formation of a callus fibrosus ; 

 fractures of the pubis often recur, especially if the animal soon after- 

 wards becomes pregnant. Fracture of the ischial shaft (4a) often 

 fails to unite, and the animal is only of use for slow work. In a 

 case of Moller's there was still marked crepitation after eight weeks, 

 but complete union occurred in four months, and the animal could 

 be put to trotting work. The fact that pain is not severe favours 

 movement and displacement of the fragments, and interferes with 

 recovery. 



(4) Extensive fractures of the tuber ischii usually unite very slowly, 

 and sometimes result in the toe being dragged and the M. biceps 

 femoris thrust out of position during movement ; small fractures 

 may be overlooked, lameness being absent. 



(5) Fractures through the obturator foramen are dangerous on 

 account of the risk of injury to blood-vessels and of serious bleeding. 

 Permanent lameness may result from the obturator nerve being 

 involved in the callus. Otherwise they are rather more hopeful 

 than the following, because, though rare, yet union may occur, and 

 the animal become capable of work. 



Division of the pelvic girdle close to the symphysis pubis and 

 parallel with it sometimes produces little disturbance ; but union 

 is always slow and incomplete, while in many cases it fails to occur. 

 Laser saw a case where the bladder had been nipped between the 

 pieces of bone. Such fractures tend to recur, especially if the animal 

 be moved too early, or give birth to a foal. 



(6) Fractures of the acetabulum are the most dangerous, because 

 as a rule the wall of the cotyloid cavity is broken into several pieces ; 

 prognosis is generally unfavourable, though exceptionally union 

 is well effected, enabling the horse to resume work. 



Fracture of the pelvis through the sacro-iliac symphysis is 

 generally incurable, the danger being that, although only one side 



