170 Anatomy Applied to Medicine and Swgery. 



about one inch below the promontory of the sacrum. The 

 .longitudinal planes may be represented by vertical lines, 

 drawn upwards from the middle of Poupart's ligament 

 (Quain, Gray), or, as suggested by Anderson, in Morris' 

 Anatomy, the outer border of the rectal muscles. The 

 latter boundary, i.e., Anderson's, gives a broader space 

 for the inguinal regions, and, besides, contains the whole 

 of the inguinal canal. The names of these regions or divi- 

 sions resulting from the above lines are : For the upper 

 segment, the epigastric with the hypochondriac on either 

 side ; for the middle segment, the umbilical with the lum- 

 bar on either side, and for the lower segment, the hypo- 

 gastric with the inguinal laterally. The location of the 

 viscera occupying these regions will" be summarized after 

 the individual organs have been described. 



Structures forming the Abdominal walls. 

 1. The anterior abdominal muscles. These muscles are 

 covered by the integument and by the superficial fascia, 

 which is divisible into two layers, a subcutaneous and a 

 deeper layer. The latter is denser than the former, con- 

 tains a number of yellow elastic fibres and is loosely at- 

 tached to the underlying aponeurosis of the external 

 oblique, excepting at the linea alba and umbilicus, where 

 the union between these structures is quite firm. In the 

 inguinal region, these layers are separable and have the 

 superficial vessels and the lymphatics between them, and 

 in this region the deeper layer, termed the "fascia of 

 Scarpa," passes over Poupart's ligament and is attached 

 to the fascia lata immediately below the ligament. Inter- 

 nally, however, this deeper layer of the superficial fascia 

 is unattached to the deeper structures between the pubic 

 spine and the symphysis pubis, but spreads out to form, 

 with some involuntary muscular tissue, the dartos of the 

 scrotum. Nerve supply. These superficial structures are 



