240 THE ABDOMEN AND PELVIS 



In this way nine regions are mapped out on the surface. The three 

 median areas are named, from above downwards, the epigastric, umbilical, 

 and hypogaslric regions ; the six lateral areas are, the right and left hypo- 

 chondriac, lumbar, and iliac regions, in that order from above downwards. 



In addition to the above,, the Transpyloric Plane is 

 exceedingly useful. It is a transverse plane, which passes 

 horizontally through the mid-point of the line joining the 

 jugular (suprasternal) notch to the symphysis pubis, and it 

 crosses the linea semilunaris at the costal margin (tip of the 

 ninth costal cartilage). Posteriorly, it corresponds in level with 

 the lower part of the body of the first lumbar vertebra. 



The Superficial Fascia in the upper part of the anterior 

 abdominal wall is directly continuous with the corresponding 

 layer of the thoracic wall. Below it consists of (i) a superficial 

 fatty stratum, known as Camper's fascia, which is continuous 

 with the superficial fascia of the thigh, and (2) a deeper 

 membranous layer, which is in direct contact with the aponeurosis 

 of the external oblique muscle, no deep fascia intervening. 

 The latter is known as Scarpa's fascia. It descends on each 

 side in front of the inguinal ligament, and blends with the fascia 

 lata of the thigh immediately below and nearly parallel to that 

 structure. In the middle line it is carried down in front of the 

 pubic bones and becomes continuous with the fascia of Colles, 

 which invests the penis and scrotum, and forms the roof of the 

 superficial perineal pouch (p. 376). In cases of extravasation 

 of urine or of severe haemorrhage into the pouch (p. 376), the 

 lines of attachment of this fascia are accurately demonstrated. 



Superficial Nerves. The skin of the anterior abdominal 

 wall is supplied by the anterior cutaneous branches of the lower 

 six thoracic said first lumbar nerves. The tenth thoracic supplies 

 the skin in the neighbourhood of the umbilicus. The ilio- 

 hypogastric and ilio-inguinal nerves are both derived from L. i ; 

 the latter reaches the surface at a lower level than the f ormej, and 

 supplies the skin over the tubercle (spine) of the pubis, the upper 

 part of the scrotum, and the proximo-medial part of the thigh. 



On the lateral aspect of the abdominal wall the skin is supplied 

 by the lateral cutaneous branches of the seventh-eleventh 

 thoracic nerves. Corresponding branches from the twelfth 

 thoracic and ilio-hypogastric descend over the iliac crest to 

 supply the skin of the gluteal region. 



The anterior rami (ant. prim, divisions), which give off 

 these various branches, descend obliquely as they pass round 



