Fejas Please log in to add your comment. The mean and standard ;elvimetria of the measured diameters were: The morphometric characteristics of the pelvic cavity are important to be described, so pelvimetria clinica obstetrician can identify and diagnose cephalopelvic disproportion of a narrow pelvis and correctly pelvimetria clinica a cesarean Santin. Statistical clinjca difference in the comparison between the mean results of each diameter between the different age groups. There are several types of dystocia, pelvimetria clinica most common is cephalopelvic disproportion Lenhard et al. The variations in the pelvic parameters pelvimetria clinica Mexican women have not pelvimetgia reported in the literature, so it is important to compare these with pelvimetria clinica populations as well as associate any differences regarding age. All measurements are reported in centimeters and were stored in a database for subsequent statistical analysis.

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From the Department of Obstetric, Gynecology and Reproductive, University of TexasHouston Health Science Center, Houston, Texas The word pelvimetry is of hybrid origin; discussion of fetopelvic relationships, be- pelvi- is a combining form of the Latin word cause the station of the presenting part pelvis basin and metron is a Greek word may impact on the performance of clinical for measure.

Literally, then, pelvimetry means pelvimetry. This can be accom- plished by several methods: manually, instru- mentally using a device like a caliper, and Anatomy of the Bony Pelvis radiographically. The last 2 have, I believe The basic conguration of the bony pelvis is appropriately, fallen into disuse, but manual, that of a truncated, bent cylinder Fig. Anteriorly, the left and In a symposium devoted to vaginal deliv- right pubic bones are joined at the cartilagi- ery, this chapter on clinical pelvimetry is nous pubic symphysis.

Posteriorly, the hips fundamental and therefore placed at the articulate with the sacral alae wings at the beginning. Because an understanding of left and right sacroiliac joints. The coccyx pelvic anatomy is essential to mastering the attaches to the inferior aspect of the sacrum.

Then the important aspects from the true pelvis below by the plane of of clinical pelvimetry are presented; these the pelvic inlet.

Starting with the symphysis techniques can be learned on a model of pubis and moving clockwise, a somewhat the bony pelvis, but they must be practiced oval shape can be inscribed in this plane: on living women to appreciate the limita- symphysis, right superior pubic ramus, right tions imposed by soft tissue and the discom- linea terminalis, right sacral ala to the sacral fort associated with the complete exam- promontory and returning to the symphysis ination.

The chapter concludes with a in mirror image fashion on the left. To orient a model of the bony pelvis in Correspondence; Edward R. E-mail: Edward. Yeomans uth. Unauthorized reproduction of this article is prohibited.

Clinical Pelvimetry woman. Also, in the upright woman, the inter- nal aspect of the pubis faces more upward than backward, whereas the internal aspect of the sacrum faces more downward than forward. This will be an important concept when we consider measurement of the diagonal conjugate. The shape of the pelvic inlet accounts for the 4 basic pelvic types: anthropoid long, narrow oval , platypelloid short, wide oval , FIGURE 1. A line diagram that depicts the gynecoid almost circular, but slightly at- geometry of the bony pelvis as a truncated bent tened in the anteroposterior dimension , and cylinder.

For a visual refer- ence, the reader is referred to Figure 3. Held in the inlet and is bounded laterally by the iliac this manner, it can be seen that the plane crests and right and left iliac fossae. The of the inlet forms approximately a 50 angle false pelvis lacks obstetric signicance and with the horizontal Fig.

The shape of the pelvic inlet in makes with the horizontal. This enables the examiner to con- The true pelvis has great obstetric signi- clude only that the DC is. A outlet enable the discerning examiner to further assumption is that subtracting 1. However, the inlet is the upper obstetric conjugate OC , the shortest AP boundary of the true pelvis and thus least diameter of the pelvis through which the accessible to physical examination.

In the fetal head must pass. An OC , Finally, in all angle formed by the union of the left and instances in which the presenting part has right superior pubic rami on their posterior entered the true pelvis, the DC cannot be aspects.

Proceeding inferiorly, important clinically assessed. Despite these signicant pelvic features include the width of the sac- limitations, the estimation of the DC is one rosciatic notch in the living woman, this of the few elements of clinical pelvimetry notch is converted to the greater sciatic fora- that has stood the test of time. Clinical pelvim- and angulated as descriptors. Calling it a ret- etry, then, consists of a series of maneuvers ropubic angle, whereas not entirely accurate, designed to assess these important anatomic emphasizes the proper assessment of the features.

It is insufcient to classify a partic- anterior aspect of the inlet. The examiner ular pelvis into one of the 4 basic types because should bring 2 ngers up under the pubic mixed architectural features are encountered on arch, then acutely drop the wrist and palpate a daily basis in clinical practice.

Clinical Pelvimetry In an android pelvis, the retropubic angle is sharp and acute. In the platypelloid pelvis, THE INLET the angle is so at that it nearly forms a The assessment of the diagonal conjugate straight angle, similar to feeling a DC provides the clinician with information blackboard. In the gynecoid pelvis, the ret- regarding the anteroposterior AP diameter ropubic angle starts out at in the midline of the pelvic inlet. There are, however, sig- but then curves gently backward laterally.

In an anthropoid pelvis, the backward curve First, to ever reach the sacral promontory, is detected earlier and curves back more the examiner must drop both wrist and sharply.

The distance from the tip of the mid- mation is missed by the inexperienced dle nger to the point of contact on the back examiner. Clinical Pelvimetry directed posteriorly toward the sacrum. In all slope of the pelvic sidewall a vague term pelvic types, the lower sacral vertebrae can that relates to the inner surface of the ischium usually be reached.

A forward lower one can be determined. Practically speaking, the third of the sacrum should alert the examiner sidewalls are described as either straight to the possibility of an android pelvis, the parallel or convergent, the latter suggest- most dangerous type of pelvis if instrumen- ing a funnel-shaped or android pelvis. In tal assistance is contemplated.

Following the 30 years of performing clinical pelvimetry, anterior aspect of the sacrum superiorly as I have never characterized a pelvis as having high as possible can give the impression divergent sidewalls. Nevertheless, such a of either a hollow or at sacrum, the latter description exists in the literature and is being much less common.

With the palmar referred to as a blunderbuss pelvis,3 itself or volar surface of the ngers still directed an archaic term. Before leaving the assess- posteriorly, the ngers should slowly move ment of the midplane, I would briey like to the lateral border of the sacrum, where to comment on the bispinous diameter, the the sacrospinous ligament originates.

This narrowest transverse pelvic diameter through bandlike structure can be traced further lat- which the fetal head must pass. Regrettably, erally to its insertion on the ischial spine, this diameter cannot be readily assessed and the entire length of the ligament can clinically.

Some authors suggest separating be estimated in ngerbreadths. The sacro- the examining ngers as widely as possible spinous ligament converts the sacrosciatic and that in rare contracted pelves, one may notch not clinically accessible for evalua- be able to span the distance between the tion to the greater sciatic foramen.

Once spines. I have never found this helpful. The again, the length and direction of this liga- perpendicular diameter that begins at the ment gives important clues to the overall inferior margin of the symphysis, extends pelvic type.

The ligament length is normally to the hollow of the sacrum at around the estimated in ngerbreadths, a disadvant- junction of the third and fourth sacral verte- age given the varying size of modern exam- brae, and bisects the bispinous diameter is iners ngers. Less than 2 ngerbreadths also difcult to assess clinically. The line implies a narrow sacrosciatic notch, a fea- segment that originates at the junction of ture of an android pelvis. A 3-ngerbreadth the AP and transverse diameters of the mid- ligament that is directed more laterally than plane and extends to the sacrum posteriorly anteriorly suggests a platypelloid pelvis.

The is referred to as the posterior sagittal diam- ligament in an anthropoid pelvis is also 3 or eter. The posterior sagittal diameter see Fig.

The gynecoid pelvis has a sacrospinous ligament that is intermediate between narrow and wide. Following the ligament from the lateral border of the sacrum to the ischial spine is the best method of locating the spine and is essential for proper performance of a pu- dendal nerve block.

Once the spine has been reached, the examiner should record a qualitative description using the terms promi- nent, blunt, or average. Just anterior to the ischial spine is the interior surface of the ischium. The posterior sagittal diameter in ipsilateral ischial tuberosity externally, the the plane of the ischial difcult to assess clinically. Recently, one of both, but I have no special secret on how to our residents completed a research project in assess the posterior sagittal diameter clini- which the BTD was estimated as a dichoto- cally either.

Conceptually, if one were to mous variable ,8 cm,. The technique spines as partitioning the pelvis into anterior described more than 50 years ago was used, and posterior halves, then a long posterior placing the previously measured st exter- sagittal segment bespeaks available room nally between the ischial tuberosities.

The for the fetal head in the posterior pelvis, a study yielded the clinically and statistically favorable sign. The rst is episiotomy compared with a BTD. Both the shape and mobility of age. A narrow BTD is a very strong indica- the coccyx should be described. Next, the tor of an android pelvis, although occasion- subpubic not to be confused with the retro- ally a narrow BTD can also be found in an pubic discussed earlier angle is estimated, anthropoid pelvis.

Whether a narrow BTD which gives information about the pubic may be an indication for a mediolateral arch. A gynecoid pelvis has a subpubic rather than a midline episiotomy was not angle. However, examiners do not usually have a protractor Fetopelvic Relationships or a goniometer handy during the perform- The preceding description of the basic tech- ance of clinical pelvimetry. Therefore, the niques of clinical pelvimetry serves to set examining ngers once again can be used the stage for practical application of this to advantage.

A gynecoid pelvis has a sub- art. One of the risks of vaginal breech deliv- pubic arch characterized as Norman, that ery is head entrapment not by just the cervix, is, rounded and roomy; the 2 examining n- but by a contracted bony pelvis.

Fetal heads gers can be raised, ventral side up, all the in cephalic presentations have ample time to way to the lower border of the symphysis mold, ex, and adapt to a relatively con- without being displaced. Then palpation of tracted pelvis, but the aftercoming head of the descending pubic rami which form the breech must negotiate the pelvis in sec- the hypotenuses of 2 mirror-image right tri- onds to minutes.

I believe, as did the authors angles with the apex at the symphysis and of the Term Breech Trial,4 that a pelvis can the base along the bituberous diameter be clinically determined by an experienced bisected in the midline will trace out a examiner to be adequate for vaginal breech rounded arch terminating in the tuberosities. Others feel strongly that computed In contrast, the examining ngers will often tomographic pelvimetry is indicated in just be forced to overlap at the top of the this circumstance.

Luikart forceps with a sliding eries. A separate article in this symposium lock were placed, the asynclitism was cor- deals with vaginal breech delivery. There was no birth trauma, the infant taking operative vaginal delivery. Too much was vigorous, and the episiotomy did not emphasis has been accorded to the estima- extend.

This case demonstrates the contribu- tion of fetal weight by either clinical or sono- tion of pelvic assessment to achievement of graphic methods, neglecting the importance a vaginal delivery with an excellent maternal of careful clinical pelvimetry. The overall and fetal outcome. The bony pelvis itself may be primary cesarean delivery. In a woman adequate but fetal malposition, deexion, undergoing labor augmentation with oxyto- and asynclitism may contribute to an arrest cin, adequate contractility of Montevi- of descent.

Correction of the fetal abnormal- deo units was achieved. No progress in dila- ity may reveal that the pelvis was clinically tion ensued over 2 hours. Recent work sug- adequate despite inability to achieve a spon- gests extending the labor for another 2 hours taneous delivery.

Consider the following before resorting to cesarean,6 but vaginal representative case.


Pelvi (o bacino)



Anatomía obstétrica, pelvimetría


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