ABDOMINAL WALL 383 



digitations of the external oblique muscle, and then each 

 divides into an anterior and posterior division. The posterior 

 divisions are small, and are directed backwards over the latis- 

 simus dorsi. The anterior divisions run forward, and a careful 

 dissector may trace them as far as the lateral margin of the 

 rectus abdominis. 



The lateral cutaneous branch of the last thoracic nerve differs 

 from the other members of the series in not dividing into an 

 anterior and a posterior branch, and in being destined for 

 the supply of the integument over the glutaeal region. It 

 pierces the external oblique muscle, in a line with the other 

 lateral nerves, and is then directed downwards over the 

 crest of the ilium. It crosses the iliac crest from one to 

 two inches behind the anterior superior spine. 



The lateral branch of the ilio-hypogastric nerve is also dis- 

 tributed to the skin of the glutaeal region. It pierces the 

 external oblique immediately above the iliac crest, which it 

 usually crosses opposite the tubercle which projects from the 

 lateral lip of the crest, about two and a half inches behind 

 the anterior superior spine of the ilium. 



Arterise Cutaneae (Cutaneous Arteries). Cutaneous 

 arteries are found accompanying the cutaneous nerves. 

 Those which are associated with the lateral cutaneous nerves 

 are branches of the aortic intercostal arteries, whilst those in 

 relation to the anterior cutaneous nerves are derived from the 

 superior and inferior epigastric arteries. 



In addition to these, three small branches of the femoral 

 artery ramify in the superficial fascia of the groin. 



These are 



1. The superficial external pudendal. 



2. The superficial epigastric. 



3. The superficial circumflex iliac. 



They take origin in the thigh, a short distance distal to 

 the inguinal ligament, and, piercing the fascia lata, diverge 

 from each other in the superficial fascia. 



The superficial external pudendal is directed medially over 

 the spermatic cord. It gives branches to the skin of the 

 scrotum and under surface of the penis. 



The superficial circumflex iliac proceeds laterally and 

 upwards along the line of the inguinal ligament (Poupart's), 

 and ends in the skin in the neighbourhood of the anterior 

 superior spine of the ilium. 



