Landmarks Medical and Surgical

by Luther Holden; James Shuter

In very corpulent persons two deep transverse furrows run across the abdomen. One runs across the navel and completely conceals it. The other is lower down, just above the fat of the pubes. In tapping the bladder above the pubes in such a case, the trochar should be introduced where this line intersects the linea alba.

Although the position of the umbilicus varies a little in different persons, as the abdomen is unusually protuberant or the reverse, still, as a general rule, it is placed about the level of the body of the third lumbar vertebra. Now, since the aorta divides a little below the middle of the fourth lumbar, it follows that the best place to apply pressure on this great vessel is one inch below the umbilicus, and slightly to the left of it ([65]). That the aorta can, under favourable circumstances, be compressed under chloroform sufficiently to cure an aneurysm below it, is proved by recorded cases, and by none more effectually than by a case related in the second volume of the ‘Reports of St. Bartholomew’s Hospital.’

It may be asked, why not apply pressure on the aorta above the umbilicus? The answer is, that the aorta above the umbilicus is farther from the surface, and is, moreover, covered by important structures upon which pressure would be dangerous.

63. Parts behind linea alba.—Let us next consider what viscera lie immediately behind the linea alba. For two or three fingers’ breadth below the ensiform cartilage there is the left lobe of the liver, which here crosses the middle line. Below the edge of the liver comes the stomach, more or less in contact with the linea alba, according to its degree of distension. In extreme distension the stomach pushes everything out of the way, and occupies all the room between the liver and the umbilicus. When empty and contracted, it retreats behind the liver, and lies flat in front of the pancreas at the back of the abdomen; thus giving rise to the hollow termed the ‘pit of the stomach.’ But as the stomach distends, it makes a considerable fulness where there was a pit. The middle of the transverse colon lies above the umbilicus, occupying space (vertically two or three inches) according to its distension. Behind and below the umbilicus, supposing the bladder contracted, are the small intestines, covered by the great omentum.

64. Peritoneum.—The peritoneum is in contact with the linea alba all the way down to the pubes, when the bladder is empty. But when the bladder distends, it raises the peritoneum from the middle line above the pubes; so that with a bladder distended half-way up to the umbilicus, there is a space of nearly two inches above the symphysis where the bladder may be tapped without risk of injury to the peritoneum. For the same reason, we have space sufficient for the successful performance of the high operation for stone. This fact in anatomy must have been well understood by Jean de Dot, the smith at Amsterdam, who, in the seventeenth century, cut himself in the linea alba above the pubes, and took out of his bladder a stone as large as a hen’s egg. The stone, the knife, and the portrait of the operator, may be seen to this day in the museum at Leyden.

65. Division of Aorta.—The aorta generally divides at a point one inch and a half below the umbilicus. A more reliable guide to this division than the umbilicus, is a point (a very little to the left) of the middle line about the level of the highest part of the crest of the ilium. A line drawn with a slight curve outwards from this point to the groin, where the pulsation of the common femoral can be distinctly felt (rather nearer to the pubes than the ilium), gives the direction of the common iliac and external iliac arteries. About the first two inches of this line belong to the common iliac, the remainder to the external. Slight pressure readily detects the pulsation of the external iliac above ‘Poupart’s ligament.’

As a rule, the length of the common iliac is about two inches, but it should be remembered there are frequent deviations. It may be between three-quarters of an inch and three inches and a half long. These varieties may arise either from a high division of the aorta, or a low division of the common iliac, or both. It is impossible to ascertain during life what is its length in a given instance, for there is no necessary relation between its length and the height of the stature. It is often short in tall men, and vice versâ. Anatomists generally describe the right as a trifle longer than the left; but their average length is pretty nearly the same.

66. Mr. Abernethy, who in the year 1796 first put a ligature round the external iliac, made his incision in the line of the artery. But the easiest and safest way to reach the vessel is by an incision (recommended in the first instance by Sir Astley Cooper, and now generally adopted), beginning just on the inner side of the artery, a little above Poupart’s ligament, and continued upwards and outwards a little beyond the spine of the ilium. The same incision extended farther in the same direction would reach the common iliac.

67. Bony prominences.—The anterior superior spine of the ilium, the spine of the pubes, and the line of Poupart’s ligament, are landmarks with which every surgeon should be thoroughly familiar.

68. Spine of ilium.—The spine of the ilium is the spot from which we measure the length of the lower extremity. It is a valuable landmark in determining the nature of injuries to the pelvis and the hip. The thumb easily feels the spine, even in fat persons. Its position with regard to the trochanter major should be carefully examined. The best way to do this is to place the thumbs firmly on the opposite spines, and to grasp the trochanters with the fingers. Any abnormal position on one side is thus easily ascertained with the sound side as a guide.