TRAUMATIC INJURIES 107 



luxation subsequently tie the free end of the line to the collar and thus 

 restrain the animal from carrying the foot backwards as is necessary 

 in flexing the stifle. The result is that the patella is kept in a 

 stationary position on the trochlea and the ligaments are relaxed. 

 This contributes to their contraction after the undue tension to 

 which they have been subjected. 



TRAUMATIC INJURIES 



Traumatic injuries in the neighbourhood of the stifle should be 

 treated with great care. It will be remembered that a pouch of the 

 synovial membrane of the external femoro-tibial joint extends some 

 distance along the tendon of the flexor metatarsi and extensor pedis 

 muscles, and also that a diverticulum from the anterior synovial mem- 

 brane extends beneath the tendon of the quadriceps extensor cruris. 

 Thus injuries in the region of the middle straight ligament of the 

 patella may lead to inflammation and suppuration of the anterior or 

 femoro-patellar synovial membrane, and subsequently, in those cases 

 where communication between this membrane and the two lateral ones 

 exists, to a spreading of these affections to the whole joint. Similarly, 

 but in cases which are much more rare, an injury to the extensor pedis 

 tendon some two inches below the upper level of the anterior and 

 external tibial tuberosities, may lead to inflammation of the whole of 

 the stifle joint. Most commonly, however, such an injury leads to an 

 affection of the outer lateral synovial membrane only. 



In such cases, when the whole joint becomes affected, there is great 

 swelling, which is diffused and extends all around the joint. It is most 

 prominent in front, since the powerful lateral ligaments prevent any- 

 very extensive bulging of the synovial capsules laterally. The indenta- 

 tion which is normally seen just below the patella in a healthy stifle,, 

 and to which attention was called in our superficial description, quickly 



