Chap. XIX.] SCARPA'S TRIANGLE. 437 



a rupture about the middle of the muscle united by 

 fibrous tissue. The adductor muscles, and especially 

 the adductor longus, are frequently sprained or even 

 partially ruptured during horse exercise, the grip of 

 the saddle being for the most part maintained by 

 them. "Rider's sprains," as such accidents are 

 called, usually involve the muscles close to their pelvic 

 attachments. Much blood is often effused when the 

 fibres are ruptured, and such effusion may become 

 so dense and fibrinous as to form a mass that has 

 been mistaken for a detached piece of the pubes 

 (Henry Morris). The term " rider's bone " refers to 

 an ossification of the upper tendon of the adductor 

 longus or magnus, following a sprain or partial 

 ruptura Cases are reported where the piece of bone 

 in the tendon was half an inch, two inches, and even 

 three inches long. 



Blood-vessels. The femoral artery occupies so 

 superficial a position in Scarpa's triangle, that it is not 

 infrequently wounded. The vessel also has been 

 opened up by cancerous and phagedsenic ulcerations of 

 this part, the occurrence leading to fatal haemorrhage. 

 Pressure is most conveniently applied to the artery at 

 a spot immediately below Pou part's ligament, and 

 should be directed backwards, so as to compress the 

 vessel against the pubes and adjacent part of the hip 

 capsule. Lower down, compression should be applied 

 in a direction backwards and outwards, so as to bring 

 the artery against the shaft of the femur, which lies 

 at some distance, to its outer side. Pressure rudely 

 applied by a tourniquet may cause phlebitis by 

 damaging the vein, or neuralgia by contusing the 

 anterior crural nerve. 



From the near proximity of the arteiy and vein, 

 it happens that arterio-venous aneurisms following 

 wound have been met with in this situation. Aneu- 

 rism is frequent in the common femoral, and many 



