740 LUXATION OF THE SACRO-ILIAC ARTICULATION. 



ilium. In cattle the union is less firm, the upper sacro-iliac ligament 

 being sometimes absent. For this reason these animals occasionally 

 suffer incomplete or complete separation of the sacrum from the 

 ilium, especially during parturition. Stockfleth and Berdez have 

 thoroughly studied the condition, and their description is here 

 followed. Berdez, considering the mode of origin of this dislocation, 

 lays particular stress on the atony of the abdominal muscles which 

 occurs at the time of parturition. Of these the rectus abdominis 

 appears to act in opposition to the ligamentous apparatus described, 

 and fixes the joint. When, therefore, it is relaxed as during 

 parturition, danger of displacement becomes imminent. Stockfleth 

 believes that movement in the symphysis pubis favours displace- 

 ment. If division occurs in the symphysis pubis, the sacro-iliac 

 joint is endangered, hence the simultaneous occurrence of the two 

 conditions as related by Golis. It will also be clear that dislocation 

 on one side may readily lead to a similar accident on the other. It 

 is even the rule to meet with double-sided dislocation, as noted by 

 Albrecht, Guillebeau, and others. 



According to Stockfleth, incomplete luxation is often occasioned 

 in pregnant cows by pulling on the tail to assist them in rising, and 

 complete luxation then follows. It may also be caused by violent 

 muscular exertion. The psoas magnus and longissimus dorsi, with 

 a group of the thigh muscles, draw the sacrum downwards, whilst 

 the glutei and other muscles of the thigh move the inner angle of the 

 ilium outwards, Powerful contractions in these muscles, produced 

 by the animal rising or walking, may thus occasion dislocation of 

 the bones. 



In incomplete luxation, the union between ilium and sacrum is 

 not completely broken down. The muscles are partly torn through, 

 and become infiltrated with blood, but the ligaments are only partly 

 divided. In complete luxation, on the other hand, all the liga- 

 mentous structures are ruptured, and the sacrum sinks between 

 the inner angles of the haunch, its anterior portion especially, so 

 that the articular surfaces may sometimes be 1 to 2 inches below the 

 inner angle of the ilium. In consequence, the abdominal organs 

 are compressed and sometimes injured ; even the passage of faeces 

 may be interfered with. 



Symptoms and course. After complete dislocation, the animal 

 is inclined to rest continuously, rises with difficulty, and when moving 

 takes short stumbling steps with the hind-legs. Sometimes large 

 quantities of faeces are passed, a symptom which Stockfleth considers 

 characteristic of dislocation. Pressure between the inner angles 



