THE THIGH 



187 



two out of every five subjects the obturator artery, on one or on both sides, 

 takes origin from the inferior epigastric artery. In these cases it passes 

 posteriorly to gain the obturator sulcus in the upper part of the obturator 

 foramen. According to the point at which it arises from the epigastric 

 trunk, it presents different relations to the femoral ring. In the majority 

 of cases it proceeds posteriorly in close contact with the external iliac vein 

 and on the lateral side of the femoral ring. In this position it is in no 

 danger of being wounded in operations undertaken for the relief of a 

 strictured femoral hernia. In about thirty-seven per cent, however, of the 



Profunda femoris artei 



Lateral circumflex 

 artery 



Intermediate cuta- 

 neous nerve (O. T. 

 middle cutaneous) 



Lateral cutaneous nerve 



Inguinal ligament (Poupart's) 



Superficial circumflex iliac artery 

 Femoral nerve 

 | Superficial epigastric and 

 superficial pudendal arteries 



Deep external 

 ^fc^ /?,' pudendal artery 



Adductor brevis 

 Femoral vein 



Great saphenous 

 vein 



Femoral artery 



FIG. 70. Dissection of the Trigonum Femorale. 



cases, in which it exists, the artery is placed less favourably. In these, it 

 either proceeds posteriorly across the septum femorale which closes the 

 opening into the canalis femoralis, or it arches over it and turns posteriorly 

 on the medial side of the ring upon the deep aspect of the base of the 

 lacunar ligament. In the latter situation it is in a position of great danger, 

 seeing that it is the base of the lacunar ligament against which the surgeon's 

 knife is generally directed for the relief of strictured femoral hernia. 



1 



Dissection. The femoral triangle may now be dissected. To bring its 



boundaries into view the deep fascia must be removed from the anterior 



the proximal third of the thigh ; in the distal two-thirds, the 



