1440 



CLINICAL AND TOPOGRAPHICAL ANATOMY 



If it simulate a femoral hernia, examination of the back and the fact that the swelling is below 

 the fossa ovalis will prevent mistakes. Three nerves come into the thigh between the pelvis 

 and Poupart's ligament, i. e., the lumbo-inguinal (genito-crural) in the femoral sheath, the 

 femoral (anterior crural) between the iliacus and psoas and the lateral cutaneous close to the 

 lateral attachment of the inguinal ligament. 



The obturator nerve divides into two in the obturator foramen, the two divi- 

 sions being separated by some fibres of the obturator externus, and lower down by 

 the adductor brevis. The relations, course, and distribution of this nerve, in the 

 medial fibres of the psoas, over the sacro-iliac joint and under the ilio-pelvic or 

 sigmoid colon (Hilton), through the obturator foramen with its branches (from 

 the superficial division) through the cotyloid notch to the hip, and (from the deep) 



Fig. 1159. — Femoral and Obturator Nerves. (Ellis.) 

 Femoral vein Femoral artery 



Pectineus 

 Obturator (anterior div.) 



Obturator (posterior 

 division) 



Sartorius 



Iliacus 



Adductor longus 



Adductor brevis 



Obturator (anterior 



division) / 



Gracilis 



Femoral 

 Psoas 

 iilL ' Tensor fasciae latae 



Profunda artery 



Pectineus 

 Rectus femoris 



Adductor magnus 

 Geniculate branch of obturator 



Semi-membranosus 



Saphenous 



Nerve to vastus medialis 



Adductor longus 



Femoral artery 



Genu suprema artery 

 Patellar branch of saphenous 



along the popliteal artery to the knee, and others to the lower third of the thigh, 

 and sometimes the upper and medial aspect of the leg (Hilton), may be of much 

 surgical importance, e. g., in carcinoma of the bowel, disease of the sacro-iliac and 

 hip-joints, growths of the pelvis, and the rare obturator hernia. The distribution 

 of the cutaneous nerves is shown in fig. 1 158. Lying superficially in the base of 

 the trigone, the inguinal lymphatic nodes can be detected in a thin person (fig. 

 1172). ^ ^ 



The fossa ovalis (saphenous opening). — The depression corresponding to this 

 IS placed just below thelacunar (Gimbernat's) ligament, with which its upper ex- 

 tremity blends. Its centre is about 3.7 cm. (1^ in.) below and also lateral to a 



