Presentation of the Trunk.—We do not share Depaul's opinion to the effect that transverse presentations may be recognized by auscultation, for, although The line of diminution of heart-sounds does extend in a transverse direction in these presentations, this rule is not without ex ceptions. The fcetus is never horizontally, but always obliquely placed in transverse presentations, its back is at times in front and again behind, and finally the fcetus is more or less below the superior strait, in which case palpation is superior to auscultation.
Diagnosis of the Positions.
If, upon a transverse line dividing the uterus into two equal parts, one erects a perpendicular connecting the ensiform cartilage and the symphy sis, this line will divide the uterus into four parts, two on the right and two on the left. Now, we may state, in a general way, that, in the car dinal positions, in the right and left positions, independently of their va riety, the maximum of the heart-sounds will correspond to one of these four segments.
In head presentations, 0. I. L., the maximum will be in the left inferior segment. In head presentations, 0.I.R., the maximum will be in the right inferior segment.
In face presentations, M.I.L., in the left inferior segment.
In face presentations, M.I.R., in the right inferior segment.
In breech presentations, S.1.L., in the left superior segment.
In breech presentations, S.I.R., in the right superior segment.
Confining ourselves to head and breech presentations, let us see if one can differentiate between the different positions. We have admitted two chief varieties: anterior, posterior. The third, or the transverse, is only a sub-variety of these. Whether we admit with Depaul that the heart sounds are transmitted directly through the back, or with Tarnier, Chan. treuil and Ribemont, that they are conveyed by the thoracic walls, it is plain that the sounds will be clearer in proportion as the part transmitting them is more accessible to the stethoscope. If we now take each of these positions in order, we will see that we can easily reach a diagnosis.
1. 0.L.A. The back, or the side of the thorax which is most accessible, looks forward and to the left, so that the heart-sounds will be heard on a line extending from the left ilio-pectineal eminence to the umbilicus.
2. 0.L.P. The back, or the most accessible side, is directed backward and to the left, and the maximum intensity will extend along a line run ning from the left eacro-iliac synchondrosis to the umbilicus.
3. O.R.A. The back, or the most accessible side, being in front and to the right, the maximum intensity will be found on a line passing be tween the right ilio-pectineal eminence and the umbilicus.
4. O.R.P. The back, or the most accessible side, being behind and to the right, the maximum intensity will extend along a line uniting the right sacro-iliac symphysis and the umbilicus. In any case, consequent ly, the maximum of intensity will he, in the two inferior segments, below the horizontal line dividing the uterus into two equal parts, and in front or behind according as the position is anterior or posterior.
In breech presentations, the conditions will be the same with this differ ence, that the maximum will be above the horizontal line, and in the right or left segments, in front or behind, according to circumstances. Thus: 1. S.L.A. Maximum in the left superior segment, on a line extending from the middle of the last left false rib to the umbilicus, at a point near the median line.
2. S.L.P. Maximum on the same line, and in the same segment, but more posteriorly at a point remote from the median line.
3. S.R.A. Maximum on a straight line extending between the last right false rib and the umbilicus, in the right superior segment, at a point near the median line.
4. S. R. P. Maximum on the same line, and in the same segment, but at a more posterior point, at a point remote from the median line.
Tarnier and Chantreuil seek to show that Depaul's conclusions are too absolute, and give as the maximum points: