An anatomic approach to pelvic hemorrhage during sacrospinous ligament fixation of the vaginal vault.

OBJECTIVE: To examine the current clinical problem of life-threatening hemorrhage during sacrospinous vaginal vault suspension, define a management solution, and validate current anatomic knowledge of the area involved. METHODS: Ten cadaveric female pelves were dissected from a posterior gluteal approach and from an abdominal approach. The vascularity of the region of the sacrospinous ligament was mapped. RESULTS: There are multiple and varied collateral vascular supplies and anastomoses in the region of the sacrospinous ligament and buttock, including: 1) superior gluteal, 2) inferior gluteal, 3) internal pudendal, 4) vertebral, 5) middle sacral, 6) lateral sacral, and 7) external iliac via the circumflex femoral artery system. Anastomoses occurred in all pelves examined. The frequency of each type of anastomosis varied from 20-100%. CONCLUSION: Surgical ligation of the internal iliac artery would not likely curb massive hemorrhage during sacrospinous ligament fixation, except in certain cases of internal pudendal vascular injury. The inferior gluteal artery is probably the most commonly injured vessel in sacrospinous ligament suspension because of its location. Inferior gluteal vessel injury should be approached by the use of packing and vascular clips or packing and arterial embolization. These latter approaches should be of primary consideration in the control of hemorrhage at the time of sacrospinous ligament fixation.

Surgical landmarks of the ureter in the cadaveric female pelvis.

Our purpose was to delineate the course of the ureter in the female pelvis in relationship to several important surgical landmarks. Ten female cadavers with undissected pelves were used. The ureter was identified at the pelvic brim and traced inferiorly to the bladder. Sets of measurements (+/- 0.1 cm) that help define the location of the ureter were obtained at the three landmarks; the ischial spine, the obturator canal and the insertion of the arcus tendineus on the pubic bone. The mean distances from the ureter to the pelvic floor were ischial spine, 3.2 +/- 0.1 cm; obturator canal, 3.2 +/- 0.1 cm; and the insertion of the arcus tendineus on the pubic bone, 1.6 +/- 0.1 cm. The mean distances from the arcus tendineus to the pelvic floor were ischial spine, 1.9 +/- 0.1 cm; obturator canal, 2.8 +/- 0.1 cm; and the insertion of the arcus tendineus on the pubic bone, 3.2 +/- 0.1 cm. This study defines the relationship of the ureter to the pelvic floor through measurements taken at three landmarks. The data should be useful to pelvic surgeons and are important for the development of future surgical techniques.

Intraligamentous nerves as a potential source of pain after sacrospinous ligament fixation of the vaginal apex.

The aim of the study was to investigate the histology of the sacrospinous ligament to determine whether nerve fibers exist within the substance of the sacropinous ligament itself. Six sacrospinous ligaments were removed from 4 fixed female cadavers. Representative segments were taken from the lateral (ischial), middle and medial (sacral) portions of these specimens, sectioned by microtome, mounted, and stained with hematoxylin and eosin dyes. The fixed and stained sections were then examined using light microscopy. Nerve tissue was found to be concentrated in the medial portions of the sacrospinous ligaments, but nerves were found in all segments of the ligament. It was concluded that, nervous tissue is present and widely distributed within the body of the sacrospinous ligament. A wide variety of sizes and thicknesses are also demonstrated, suggesting a variety of functions, including possible pain reception. This fact should be taken into consideration when planning operative procedures for pelvic prolapse.

Examination of three-dimensional movements in human embryos using computer imaging technology.

This paper describes the use of computer imaging technology to study in three dimensions the dynamics of differentiations in human embryos. Three-dimensional computer reconstruction technology was used to build a series of models of the brain/face and the ear region from fixed, serially sectioned embryos at representative stages. When certain principles are followed each model can be equated to one frame on a motion picture film. The dynamics of differentiation are then revealed as changes in size, shape and position (growth movements) of multiple structures as they build the definitive arrangement.

Relationship of uterine blood flow to chorionic sac and embryo growth rates.

The embryonic period of development is characterized by marked variability in the rate of embryonic growth and development. Differences in uterine blood flow may explain this variability. We investigated the relationship between uterine artery blood flow volume (VOL), uterine artery pulsatility index (UA-PI), uterine artery resistance index (UA-RI), spiral artery pulsatility index (SA-PI), spiral artery resistance index (SA-RI), chorionic sac diameter (CSD), and crown-rump length (CRL) during 321 first trimester vaginal colour Doppler ultrasound examinations of 94 delivered or continuing pregnancies. After correcting for the confounding effect of gestational age, subject, and serum hormone levels by Analysis of Covariance, CRL was related to UA-PI (P = 0.025) and UA-RI (P < 0.001), but not to VOL, SA-PI, or SA-RI. No relationship was found between CSD and any uterine blood flow variables. Serum oestradiol levels were related to CSD and CRL (P < 0.001). No relationship was found to progesterone, maternal age, parity, or previous abortion. We conclude that differences in uterine blood flow and serum oestradiol explain some of the variability in the rate of embryo growth during the first 12 gestational weeks.

Three-dimensional development of the facial nerve path through the ear region in human embryos.

The goal was to determine how the facial nerve path forms normally through the ear region. Five three-dimensional computer reconstructions and eight wax plate-graphic, two-dimensional reconstructions were made from a group of 47 serially sectioned human embryos that were in the blastemal period of ear development, when most of the definitive arrangement is established. The size, shape, and positional changes of the facial nerve relative to the external ear and notochord were studied in both lateral and frontal views. The vertical (dorsoventral) position of the external ear region remains constant but shifts caudally. After formation, the geniculate ganglion assumes a position that gradually becomes rostrodorsal to the external ear. Facial nerve branches form and grow into regions expanding peripherally. The superficial petrosal branch appears to hold the ganglion in position as the horizontal segment of the facial nerve forms when the external ear shifts caudally. Possible growth movements explaining abnormal nerve paths are discussed.

The relationship of initial embryo crown--rump length to pregnancy outcome and abortus karyotype based on new growth curves for the 2-31 mm embryo.

The objective of this study was to determine if measurement of initial crown--rump length (CRL) is helpful in predicting low birth weight, newborn length, spontaneous abortions, or abortus karyotype. We measured CRL prospectively in 837 consecutive singleton pregnancies at the time a heart rate was first detectable with transvaginal ultrasonography and compared these measurements to normal values for the 10th through 90th centiles determined from 227 transvaginal ultrasound measurements in in-vitro fertilization and gamete intra-Fallopian transfer pregnancies with known ovulation dates. The relationship of initial CRL to birth weight and length and to abortion and abortus karyotype was analysed after all pregnancies had delivered. Initial CRL measured after the 28th post-ovulation day was predictive of subsequent abortion, but not of low birth weight or length. The abortion rate was 3.3% [95% confidence interval (CI) 1.5%, 5.1%] when initial CRL > or = 50th centile, compared to 19.4% (95% CI 15.4%, 23.4%) when < 50th centile. Initial CRL was < 50th centile in 13 out of 14 trisomic and in eight out of 10 other karyotypically abnormal aborti. These results indicate that initial CRL measured after the 28th post-ovulation day may help to identify pregnancies at increased risk of abortion due to abnormal karyotypes.

Three-dimensional reconstructions of the primary palate region in normal human embryos.

Our knowledge of the precise spatial relationships of human primary palate morphogenesis remains poorly defined. This is due to intrinsic difficulties that exist in the study of the subject matter and a lack of adequate methodologies. We present a novel new method to allow precise three-dimensional (3-D) visualization of developing embryonic structures in previously sectioned embryos. In our study we focus on human primary palate development. Five normal human embryos from the Carnegie collection were used. 3-D reconstructions appear similar to scanning electron micrographs (SEM); however, unlike in SEM studies, the original specimen has been previously sectioned histologically. 3-D reconstruction from serial sections involved 1) histological preparation of specimen, 2) projection onto digitizing board, 3) digitization, 4) automated reassembly, and 5) relay to interactive optical disc recorder. Detailed observations of each reconstruction were then made. Data generated in this manner may also be used in the near future for quantitative morphometrics. Thus, 3-D reconstruction techniques presented in this paper generated precise spatial information on the development of the human primary palate.

Computer analysis of the human embryo growth curve: differences between published ultrasound findings on living embryos in utero and data on fixed specimens.

Accurate information on the normal growth rate of the human embryo is fundamental to a better understanding of the embryonic period of pregnancy. Crown-rump length measured previously in utero (N = 227) with vaginal ultrasound in 107 in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) singleton pregnancies was compared to the greatest length of fixed human embryos from the Carnegie collection, of known developmental stage whose postovulatory ages were estimated from menstrual histories. Average crown-rump length in utero was 60% of the greatest length of the fixed specimens prior to postovulation day 33, but were equal after postovulation day 40. The growth rate of in utero embryos and fixed specimens, analyzed by computer using exponential equations, was compared to linear and polynomial equations used in previously published embryo growth tables. The exponential equation, length = exp(a + B/age), fit in utero measurements best, while the equation length = exp[a + b/exp(age)] fit the fixed specimens best. Differences between length in utero and in fixed specimens may be related to distortion of the fixed embryos resulting from the formalin fixation, to ultrasound distortion, to curling of the embryo, or to incorrectly estimated ages of the fixed specimens. Study of human embryos in utero is now practical with vaginal ultrasound.

Ultrasound evidence for variability in the size and development of normal human embryos before the tenth post-insemination week after assisted reproductive technologies.

Differences in human chorionic gonadotrophin (HCG), average chorionic sac diameter, embryo/fetus crown-rump length and biparietal diameter were determined in 107 singleton pregnancies delivered after 34 weeks, whose post-insemination age was precisely known as a result of in-vitro fertilization (n = 28) or gamete intra-Fallopian transfer (n = 79). Crown-rump lengths were interpreted in relation to the developmental stage of the embryo. A 7-fold to 10-fold difference in HCG levels was observed on post-insemination days 13-16. A 2-fold to 3-fold difference occurred in average chorionic sac diameter on days 25-36. A 2-fold difference occurred in crown-rump length on seven of 10 days prior to day 44. Biparietal diameter differed by no more than 42% from day 57-68 and 20% after day 68. Chorionic sac diameter, crown-rump length, and biparietal diameter were also related to newborn weight. The results suggest firstly that marked differences occur in the rate of early human development, secondly, that the differences occur prior to day 27 when observable cardiac activity begins, and thirdly, that the differences are minimized after day 68 when the embryonic period of development is completed.

Morphology of the pterygomandibular raphe in human fetuses and adults.

The pterygomandibular raphe as described in current anatomy textbooks is not supported by actual observations in cadavers. A study was made on 60 adult Caucasian and Negro cadavers (52 right and 58 left sides, giving a total of 110 sides) providing comparison with an earlier study on Japanese specimens. In addition, 50 fetuses (25 mm crown-rump length to term) were examined to determine the arrangement of the raphe prenatally. Variations in the morphology of the raphe region were classified into three types: Type A--only the upper portion of the raphe could be identified and had a broad, triangular shape. Type B--the buccinator and superior pharyngeal constrictor muscles were widely separated by a broad, fascial region. Type C--the raphe was absent with complete continuity of the buccinator and superior pharyngeal constrictor muscles. A prominent, narrow, tendinous band with attachments as described in current textbooks was never found in adults. There was a complete absence of the raphe in 36% of the specimens resulting in continuity of the buccinator and superior pharyngeal constrictor muscles (type C). However, the remaining adult specimens (64%) exhibited some form of a broad, fascial region that either completely (type B, 36%) or partially (type A, 28%) separated the two muscles. All of the fetuses exhibited the type B arrangement exclusively, indicating that changes in the shape of the raphe occur postnatally. The frequency of appearance of the raphe types in adults differs significantly according to race.

Morphology of the mandibulo-stylohyoid ligament in human adults.

The mandibulo-stylohyoid ligament is a consistently occurring connective tissue band or sheet that courses between the angle of the mandible and the stylohyoid ligament. Previously, in a few instances it has been variously named and described as a thickening of deep cervical fascia. Recently, Shimada et al. (1986) described the connective tissue thickening and named it the mandibulo-stylohyoid ligament because of its arrangement and attachments. In the present study the ligament was dissected in 99 adult cadavers (both white and black, 98 right sides, 95 left sides). It was present in all of the specimens examined and has been classified into three types according to refinements in its morphology. Type 1: The ligament was a thick, separate band that coursed from the region of the angle of the mandible to the stylohyoid ligament. Type 2: The ligament had the same attachments as Type 1 but was more extensive, being continuous with the stylomandibular ligament. Type 3: The ligament had the same attachments as Type 1 but was thin and less well developed. The Type 1 arrangement occurred 41% of the time, Type 2, 37% of the time, and Type 3, 22% of the time. The consistency and arrangement of the ligament suggests an important role of additional structural support in the region of the angle of the mandible and hyoid bone.

Evidence that sclerotomal cells do not migrate medially during normal embryonic development of the rat.

During embryonic development the medial part of the somite disorganizes or breaks up into sclerotomal cells which, according to many published reports, migrate medially to surround the notochord. The purpose of the study was to determine whether these cells actually migrate medially toward the notochord. Distances were measured between the notochord and the adjacent neural tube and the somite or its remnant during the period of somite disorganization. Serially sectioned, normal 10.5- to 13.5-day (d) rat embryos were used. Only transverse sections through the middle of the fourth cervical (C-4) body segment were measured, corresponding to the level of somite No. 8 (10.5 d) or its dermatomyotome remnant (10.5-11.5d) or spinal nerve C-4 (12.5-13.5d). Measurements were taken at six stages from photographic montages, all of which were made at precisely the same magnification. The notochord was the central axial structure from which the measurements were determined. The changes in distance show that during the period of somite breakup the neural tube grows dorsally, away from the notochord which lies adjacent to its ventral surface. Simultaneously the somite remnant moves laterally and dorsally, all the while maintaining its position relative to the overlying ectoderm and leaving behind a trail of sclerotomal cells. Also at each stage cell counts were made on the medial sclerotomal region of the C-4 segment. The average counts reveal that not only does the total number of cells increase substantially over the three-day period (42-7,546), but also the total number of mitoses (3.5-200), while the mitotic index decreases (9.0-2.7). High proliferative activity is apparent in the medial sclerotomal cells throughout the 3-day period. The evidence supports the conclusion that local proliferation of the trailing cells, which were left by the somite remnant as it moved dorsolaterally, causes the subsequent increase in density of the perichordal tissue, rather than an influx of migrating cells. Instead of sclerotomal cells migrating medially toward the notochord, the present study suggests that these cells retain their position relative to the notochord or central axis and that the medial sclerotomal region forms as a result of the growth movements of the surrounding structures.