ABDOMEN. 



tion of the muscles, insomuch that in some in- 

 dividuals the concavity is habitually very con- 

 siderable, as in those who carry burdens on the 

 head or in front of the body, in pregnant wo- 

 men, &c. (See Jig. 2.) 



The limit of this wall on each side is 

 indicated by a groove or fissure which passes 

 obliquely upwards and outwards towards the 

 ribs, and corresponds to the outer margin of 

 each relief, or that of the lumbar muscles ; 

 these lines also indicate the posterior limits 

 of the lateral walls of the abdomen, or the 

 flanks. Anteriorly the flank of each side is 

 continuous with the anterior wall of the abdo- 

 men ; above it is limited by the margin of the 

 thorax, and below by the margin or crest of the 

 ilium. It is concave on its surface from above 

 downwards, (except in cases of great embon- 

 point, where the concavity is obliterated,) and 

 convex from before backwards. Gerdy remarks 

 that in subjects in which the muscles have a 

 considerable development, a relief is formed 

 just above the crista ilii by the broad muscles 

 of the abdomen at their insertion into this 

 osseous border. Upon antique statues this 

 relief is in general made too prominent. 



The anterior or proper abdominal region has 

 been subdivided into smaller compartments, 

 with a view to facilitating descriptions, patho- 

 logical or otherwise. This subdivision is com- 

 pletely arbitrary, and therefore some differences 

 will be found among the various anatomical 

 authors as to the precise limits of each region. 

 That which is here subjoined, however, appears 

 to be pretty generally agreed upon in this 

 country. Lines connecting particular points 

 drawn upon the surface, mark out these subdi- 

 visions, and if planes be supposed to be carried 

 from these lines horizontally backwards to the 

 posterior wall, the cavity of the abdomen will 

 thus be divided into segments, each of which 

 has its particular portion of the abdominal 

 viscera. It is an instructive exercise for the 

 student to practise himself in examining the 

 particular viscera which correspond to particu- 

 lar regions. We are thus enabled, as Blandin 

 has remarked,* to resolve the problem, " a 

 point of the surface of the abdomen being 

 wounded deeply in a given direction, to de- 

 termine what organs have been injured ; and 

 reciprocally, an organ having been wounded 

 in a particular part of the abdominal cavity 

 by a sharp instrument, which entered in a 

 given direction, to determine what part of 

 the abdominal walls must necessarily have 

 been injured. "f 



The limits of these several regions or com- 

 partments may be thus indicated : j let a line 

 be drawn horizontally from the extremity of the 

 last rib on one side to the same point on the 

 other, and let another line parallel to the pre- 

 ceding be drawn between the two anterior 

 superior spinous processes of the ilium ; the 



* Anatomic Topographique, p. 423. 



t The division of the surface of the abdomen into 

 regions is as old as Aristotle. 



} See an engraving exhibiting these subdivisions, 

 in the article .ABDOMEN of the CYCLOPEDIA OF 

 PRACTICAL MEDICINE. 



abdominal surface is thus divided into three 

 great regions, each of which is subdivided into 

 three by means of a vertical line let fall on each 

 side from the anterior extremity of the seventh 

 or eighth rib to a point a little external to the 

 spine of the pubis. Nine regions are thus 

 marked out, the relations and boundaries of 

 which may be described as follows. 



The superior region, or that above the first 

 horizontal line, is the Epigastrium, which name 

 it derives from its close relation to the stomach : 

 (s7ri,upon, over ; yaa-Tr^, the stomach.) The epi- 

 gastrium is bounded superiorly and laterally by 

 the margin of the thorax, and its inferior limit 

 is indicated by the transverse line. The verti- 

 cal lines subdivide it into two lateral regions, 

 each of which is bounded immediately above 

 by the lower margin of the thorax, beneath 

 which these regions extend in a direction up- 

 wards and backwards : they are hence called 

 hypochondria (Wo, under, p^ov^o;, cartilage). 

 Between the hypochondria, is the proper 

 epigastric region, which at its superior part and 

 just below the xiphoid cartilage presents the 

 depression already alluded to under the name of 

 scrobiculus cordis (scrobiculus, the diminutive 

 of scrobs, a depression). 



Immediately below the epigastrium, and 

 separated from it by the superior horizontal 

 line, is the umbilical region, which has its 

 name from the presence of the umbilicus in it. 

 This region is limited above and below by the 

 two horizontal lines, and is subdivided by the 

 intersection of the two vertical lines into three 

 regions : the lateral ones are the lumbar regions, 

 so called from their correspondence with those 

 portions of the posterior abdominal wall which 

 bear the same name ; and the middle one is the 

 proper umbilical region. 



Between the inferior horizontal line and the 

 margin of the pelvis, is the hypogastrium, (vnro, 

 beneath, yac-T, the stomach). This region is li- 

 mited below in the centre by the pubis, and on 

 each side it communicates with the upper part 

 of the thigh. It is subdivided into the iliac 

 regions on each side, and the proper hypo- 

 gastric or pubic region in the centre. The two 

 former constitute the upper or abdominal 

 portion of the great region of the groin, which 

 is completed inferiorly by the upper part of the 

 anterior surface of the thigh. These regions 

 afford peculiar interest to the surgical ana- 

 tomist, in consequence of the occurrence in 

 them of the most common forms of hernia.* 

 (See GROIN, REGION OF THE.) 



The structures which enter into the com- 

 position of the abdominal parietes, or their 

 elements, (as the term has been lately applied,) 

 are 1. the skin : 2. the subcutaneous tissue 

 or superficial fascia : 3. muscles and their 

 aponeurotic expansions : 4. a particular fibrous 

 expansion, or fascia : 5. a thin and filamen- 

 tous cellular tissue, which separates the fascia 

 just named from the sixth element: 6. the peri- 

 toneum, which, however, is not to be found in the 

 composition of all the walls of the abdomen. 



* Velpeau applies the term zone to the primary 

 regions included between the horizontal lines. 

 Anat. Chirurg. t. ii. 



