206 ABDOMEN 



Arteria Circumflexa Ilium Superficialis. The superficial 

 circumflex iliac artery passes laterally and upwards, along the 

 line of the inguinal ligament (Pouparti), and ends in the skin 

 in the neighbourhood of the anterior superior spine of the 

 ilium. 



Arteria Epigastrica Superficialis, The superficial epigastric 

 artery takes a course upwards and medially, and, after 

 crossing the inguinal ligament, it ramifies in the superficial 

 fascia over the inferior part of the abdomen. Its branches 

 extend as high as the level of the umbilicus. 



The small veins which accompany these arteries open into 

 the great saphenous vein. 



Muscles of the Abdominal Wall. The abdominal wall is 

 formed anteriorly and laterally by five pairs of muscles, and by 

 the aponeuroses which constitute their tendons. Anteriorly 

 are the two recti muscles and the two pyramidales muscles. 

 The recti are placed parallel to the middle line, and extend 

 vertically from the pubic bones to the lower margin of the 

 thorax. On each side three fleshy and aponeurotic strata are 

 met with. From the surface towards the abdominal cavity 

 they are (i) the external oblique muscle; (2) the internal 

 oblique muscle ; (3) the transversus abdominis muscle. The 

 direction taken by the muscular fibres which compose each 

 of the layers is different. The external oblique corresponds 

 in direction with the external intercostal muscles ; the fibres 

 proceed obliquely downwards, forwards, and medially. The 

 internal oblique resembles the internal intercostal muscles in 

 the direction of its fibres ; they are directed upwards, medially, 

 and forwards ; thus the fibres of the two oblique muscles 

 cross each other like the limbs of the letter X. Lastly, the 

 fibres composing the transversus abdominis muscle pursue a 

 horizontal course. 



The difference of direction of the fibres which compose 

 the three strata is a source of strength to the part of the 

 abdominal wall which they form, and the arrangement offers 

 a strong barrier to the protrusion of any of the abdominal 

 contents. The two oblique muscles and the transversus are 

 prolonged to the middle line in the form of aponeuroses. 

 The union of the aponeuroses of the opposite sides forms the 

 linea alba a strong band which extends, in the median line, 

 from the symphysis pubis to the xiphoid process. 



Dissection. Remove the superficial fascia from the front of 



