A new sagittal pelvimeter

A NEW

SAGITTAL

PELVIMETER

BY H. ACOSTA-SISON, M.D., MANILA, P. I. (Assooiate

Professor

in

Obstetkx,

Unizrersity

of

the

Philip&es)

I

T IS useless for me to stress the importanee of measuring the pelvic outlet in a primipara or a multipara with the history of prolonged labor. Klien,l Williams,2 DanielsS and others have repeatedly demonstrated its value as a guide in the proper management of labor in a given case. McCormick4 gives an exhaustive review of the subject in the June number (1926) of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOCY. The engagement of the head is a satisfactory indication that the pelvic inlet is obstetrically efficient, but it does not imply that the pelvic

Fig.

l.-Acosta-Sison

pelvimeter.

outlet is equally efficient to allow the birth of the head by the natural route. On studying the table worked out by Williams in his textbook, one can safely establish a guide that as long as the transverse diameter and the posterior sagittal diameter together measure 15.5 cm. spontaneous labor is within the limit of possibility, and if the sum of both diameters is I believe that below 15.5 cm. spont.aneous labor is out of the question. to remember this is kasier than t.o memorize each number of centimeters that the po&erior sagittal must elongate for every centimeter or half a centimeter of contraction of the transverse diameter. Daniels has a somewhat different method of approaching the subject though the result is about the same. He determipes the area of the posterior triangle of the outlet and by it he may prognosticate the 760

ACOSTA-SISON

:

A

NEW

SAGITTAL

761

PELVIMETER

possibility of spontaneous labor. Multiplying the transverse diameter by the sagittal diameter and dividing the result by 2, will give the area of the posterior triangle. His formula is as follows: Tranwerse

x posterior 2

sagittnl

-

55 ml.

or the normal area for an American woman. He claims that a posterior triangle having an area of 33 cm. may allow spontaneous delivery of the child. In the paper on pelvimetry and cephalometry among Filipino women by Acosta-Sison and Ca1deroq5 it is shown that among Filipinos, 47

Fig.

Z-The

bar

may

be used

to measure

the

intertrochsnteric

diameter.

is the normal area of the posterior triangle of the outlet and that this area may be reduced to as low as 31 and yet spontaneous delivery might still be possible. The small posterior triangle given by Daniels and the even smaller measurements of Williams, which according to him will admit the possibility of spontaneous labor, may be a safe guide only when the child is small. If it is of the average size, forceps might be necessary to prevent prolonged pressure and the frequent pounding of the uterine pains on the head. When the baby is above the average size, it is doubtful that with such small measurements, the child can be extracted without deep asphyxia that will ultimately end in death.

762

THE

Fig.

Fig.

4.-Technic

AMERICAN

3.-The

cif feeling

JOURNAL

manner

of

for

the

OF’

taking

articulation

OBSTETRICS

t.he

posterior

between

AND

mgittnl

the

GYNECOLOQY

dimwtw.

sacrum

and

the

COCCYX

ACOSTA-SISON

:

A NEW

SAGITTAL

PELVIMETER

763

To measure conveniently the posterior and anterior sagittal diameters which extend respectively from the midpoi.nt of the intertrochanteric diameter to the point of the sacrum and from the midpoint of the intertrochanteric diameter to the inferior border of the symphysis, the sagittal pelvimeter herewith presented has been devised. The instrument consists of a flattened crossbar which is long enough to be fixed In the midline of the bar is attached the revolving against the ischial tuberosities. With the crossbar fixed against both ischial end of one arm of the pelvimeter. tuberosities, the pelvimeter may be made to measure the posterior sagittal diameter may be turned and without moving the crossbar from its place, the pelvimeter forward to measure the anterior sagittal diameter.

Fig.

5.--Measurement

of

the

anterior

sagittal

diameter.

The crossbar is also graduated into 0.5 to 1 cm. so that it may be used to measure the intertrochanteric diameter. As it is marked from the middle outward, the number registered by the measuring thumb should be multiplied by two in order to get the full measurement of the transverse diameter.

My technic of its use is as follows: The patient is placed on a high table in the lithotomy position with the buttocks a.t least 12 cm. beyond the edge of the table so that the lower portion of the sacrum may be felt. The thighs with bent knees should be acutely flexed over the abdomen and held in place by straps or by assistants. In this position the outlet is well exposed. After previous sterilization of the external genitalia including the ischial tuberosities and lower part of the sacrum the tuberosities as well as the sacrum should be well dried with a sterile towel to prevent the crossbar from slipping. After drying both hands, the right hand

764

THE

AMERICAN

JOURNAL

OF

OJ3STETRICS

AND

QYNECOLOGY

adjusts the crossbar against the ischial tuberosities in such a manner that the pelvimeter is exactly in the midline while the left hand feels for the tip of the sacrum and applies thereto the end of the pelvimeter. The distance between the two points, namely, the midline of the intertrochanteric diameter and the tip of the sacrum constitutes the If there is doubt in the location of the tip posterior sagittal diameter. of the sacrum, the right finger is introduced into the vagina and the coccyx is moved up and down between the two fingers until its articulation with the sacrum is reached. The anterior sagittal diameter is measured by swinging the free arm of the pelvimeter to the inferior border of the symphysis. If the above directions are carefully followed, no difficulty should be encountered in taking the sagittal diameters. No assistants are necessary except those who will have to keep the thighs flexed. Thanks are due to M. Ligaya

for the drawing

of the illustrations.

REFERENCES

Volkmann’s New York, Jour. Obst., lxxiv, No. 2. 1926, xi, No 6, 794. (5) March, 1919, xiv, No. 11.

w . (l) : Obstetrics, gEimJ

PNEUMONIA. BY M.

PIERCE

Samml. klin. Vortr. 1896, No. 169. (2) Williams, J. 1924, D. Appleton and Co. (3) Daniels, C, D.: Am. (4) McCormick : AM. JOUR. OBST. ANTI C~Y~~EC., June, Boo&z&son and Calderon, F.: Philippine Jour. SC.,

AS A SEQUEL RUCKRR,

M.D.,

TO ANESTHESIA” RICHMOND,

VA.

HEN our Secretary assigned this subject to me, Woodrow Wilson’s favorite limerick came at once to mind: I never saw a purple cow. I never hope to see one, But, I can tell you anyhow, I had rather see than be one.

This subject is of more than academic interest. As Featherstone says, it is the one condition that starts, runs its course, I have and ends while the patient is under hospital observation. been greatly interested in the history of this complication. In the early days of anesthesia, the surgeons operated with great rapidity. They had been trained on struggling patients who were held by brute force, and were not required to be thoroughly relaxed. The anesthetist was timid and was concerned chiefly with rendering the patient insensible. Dr. Cook has given us a description of the first major operation in Europe under ether anesthesia. “The patient was a man *Read tridans,

at the Thirty-ninth Gynecologists. and

Annual Abdominal

Meeting of Surgeons,

the American Chicago, Ill.,

Assoolatfon September

of Ob&e92, 1926.