Uterine first pass effect in postmenopausal women

BACKGROUND: Vaginally administered drugs distribute preferentially to the uterus; counter-current transfer from the vaginal veins to the uterine artery probably plays a pivotal role. In each side, the ovarian and uterine arteries form arterial anastomoses and controversy exists regarding the origin of the arterial supply to the Fallopian tube and tubal part of the uterus, and consequently whether these tissues can be reached through vaginal administration. METHODS: A thermocatheter with four measurement points, each separated by 5 mm, was inserted under endoscopic control into the tubal corner of uterus in 10 conscious, menopausal women and the temperatures registered every 2 s. The vagina was then flushed for 15 min with 1.5 l of saline at room temperature, after which the probe position was re-assessed by the endoscope. RESULTS: The lowest measurement point (15 mm from the tip) cooled significantly more than the other points (P < 0.0001). At 15 min, mean temperature reduction at point 4 was significantly greater than at all other measurement points (P < 0.05) due to local transfer of cold from vaginal vein blood to the uterine arterial blood (but not the ovarian artery). CONCLUSIONS: The results support the theory that, at least in postmenopausal women, the uterine artery supplies most of the uterus while the corneal part of cavity (up to 5-10 mm from the ostium) receives the blood supply from the ovarian artery. This finding represents a rationale for vaginal administration of drugs when a local effect on the uterus (e.g. progestational or relaxation) in postmenopausal women is requested.     

Study of the vasculature of the caprine reproductive organs using the tissue‐clearing technique,with special reference to the angioarchitecture of the utero‐ovarian vessels and the adaptation of the ovarian and/or vaginal arteries to multiple pregnancies

Arteries of the reproductive tracts of nonpregnant does and does at 4, 7, 10, 13, 16, and 18 weeks of gestation were injected in situ with Microfil®. The tracts were fixed, dehydrated, and rendered transparent to reveal the paths of arteries. The tortuous ovarian artery lay in close apposition to the uterine tributary of the ovarian vein, an arrangement that may serve as a local utero‐ovarian pathway for the corpus luteum (CL) luteolysis at the end of nonfertile estrous cycle. During pregnancy, this arteriovenous arrangement might transfer luteotropic substances from uterus to ovary, which might serve in maternal recognition of pregnancy and fit the fact that the goat is CL‐dependent throughout gestation. In some cases of triplets, the size of the uterine branch of the ovarian artery was equal to or even larger than that of its parent artery and/or the ipsilateral uterine artery, and the vaginal artery contributed a connecting branch to the uterine artery. These physiological adaptations of the ovarian and/or vaginal arteries, which have not previously been described, correlate well with the increasing nutrient demands of the growing multiple fetuses. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Ramification Pattern of the Arteries Supplying the Rabbit Female Genital Organs

Uterine adenocarcinoma occurs in more than 60% of female rabbits aged 4 years and over. To cure or prevent this uterine disorder, ovariohysterectomy should be performed. Although knowledge of the arterial supply to the ovary, uterus, and vagina is required, few studies have described the arterial anatomy. Therefore, we dissected ovarian, uterine, and vaginal arteries in 15 New Zealand White and 15 Japanese White rabbits to clarify the anatomy. The ovarian artery arose from the abdominal aorta, and in 50% of cases, the left artery emerged more cranially than the right artery. The ovarian artery provided the ovarian, uterine, and tubal branches with three branching types. The most frequent type (67% of the halves on the right and 63% of the halves on the left) exhibited three branches that independently arose from the ovarian artery. The uterine artery usually originated from the umbilical artery, with its ramification pattern divided into two types, having one or two uterine arteries, respectively. The most frequent type (all halves on the right and 83% of the halves on the left) had one uterine artery that originated from the umbilical artery. We observed three types of vaginal artery origins, with the branching type where the vaginal artery arose from the internal iliac artery being the most frequent (97% of the halves on the right and 90% of the halves on the left). The detailed arterial supply pattern of the rabbit female genital organs determined in the present study will be helpful when performing rabbit gynecological surgeries. Anat Rec, 303:1478–1488, 2020. © 2019 American Association for Anatomy     

Preferential vascular-based transfer from vagina to the corpus but not to the tubal part of the uterus in postmenopausal women.

BACKGROUND: Vaginal administration of progesterone during infertility treatment has therapeutic advantages over oral administration. However, the reasons for this are poorly defined. To demonstrate a preferential vagina-to-uterus distribution of substances, we investigated cold distribution from vagina to the uterus and rectum. METHOD: In 10 postmenopausal women, thermoprobes were inserted into the uterine cavity and in the rectum at <9 cm or at >9 cm from the anus; temperatures were subsequently measured during 10 min flushing of vagina with cold saline. RESULTS: After 10 min, temperature decreased as follows: uterus, tubal angle: -0.22 +/- 0.07 degrees C, 10 (mean +/- SEM, n); uterus, middle cavity: -1.26 +/- 0.34 degrees C, 9; rectum, <9 cm insertion: -3.69 +/- 0.68 degrees C, 3; rectum, >9 cm insertion: -0.51 +/- 0.19 degrees C, 6. CONCLUSIONS: Despite obviously different distances to the vagina of the uterine and the low rectal probes (<9 cm) the temperature decrease occurred at the same time. Cold transfer from vagina to the uterus and rectum is probably not the result of simple diffusion but of a vascular counter-current transfer. Differential cooling of corpus and tubal angles suggests a different arterial supply; while uterine corpus is supplied from the uterine artery, the tubal angles seem to be mainly supplied from the ovarian artery via the tubal arcade.     

数字化原位子宫动脉血管3D可视化模型的构建及意义

目的探讨构建女性原位子宫动脉血管3D可视化模型和研究子宫动脉血管的结构特征。方法采用聚乙烯醇-氧化铈血管造影术进行2例女尸盆腔动脉血管灌注,X线平位摄影、64排螺旋CT扫描后采集数据,导入计算机Mimics10.01重建软件进行子宫动脉血管3D可视化模型构建,观察子宫动脉血管的形态及血供分布情况。结果①构建的子宫动脉血管三维模型图像清晰,管道饱满,立体空间感强,均能清晰地显示子宫动脉的4级以上血管,各级分支血管的形态、走行、分布及各血管间的吻合显影清晰,效果满意。2例子宫及附件无实质性病变,为正常子宫。②清晰显示子宫动脉血管网的构建特点:子宫动脉自主干依次发出膀胱支、输尿管支、上行支、下行支等分支动脉;上行支较粗呈弓状沿子宫体侧缘迂曲上行,至宫角处分为宫底支、输卵管支和卵巢支,主要向子宫体和子宫附件供血;下行支较细分布于宫颈及阴道上段,但分布于阴道的血管较少;子宫动脉通过其卵巢支与卵巢动脉相交通;同时子宫动脉的供血还存有着明显的同侧倾向,双侧子宫动脉在子宫的中轴线处有少量细小的交通支。结论采用聚乙烯醇-氧化铈血管造影术盆腔动脉血管灌注可构建理想的子宫动脉血管网3D可视化模型,为系统研究人子宫动脉血管网的形态结构和血供分布提供了血管解剖学基础。     

胰十二指肠区动脉血管3D可视化模型的构建及意义

目的探讨构建胰十二指肠区动脉血管3D可视化模型和研究胰十二指肠区动脉血管的结构特征。方法采用128排螺旋CT对5例新鲜肝标本进行扫描,并进行三维重建。记录螺旋CT影像下胰十二指肠区血管的空间位置关系。结果构建的胰十二指肠区动脉血管三维模型图像清晰,管道饱满,立体空间感强,均能清晰地显示胰十二指肠区动脉的4级以上血管,各级分支血管的形态、走行、分布及各血管间的吻合显影清晰,效果满意。清晰显示胰十二指肠区动脉血管网的构建特点。结论采用聚乙烯醇-氧化铈血管造影术胰十二指肠区动脉血管灌注可构建理想的胰十二指肠区动脉血管网3D可视化模型,为系统研究人胰十二指肠区动脉血管网的形态结构和血供分布提供了血管解剖学基础。     

The urogenital artery of the adult dog

For this study 52 formaldehyde-fixed pelvis from both sexes dogs (Canis familiaris), unknown races and different ages, injected with latex through the aorta, were used. The results were classified in common (A) and uncommon (B, B1, B2 and B3) modalities: A-44 dogs (84.62%; 74.82-94.42%), with emergence of the urogenital artery from the visceral branch of the hypogastric artery; B-5 dogs (9.62%; 2.70-22.10%), where the vessel arises from the umbilical artery. In this manner, the intrapelvic organs (ureter, deferent duct, bladder, prostate and urethra in male, and ureter, bladder, urethra, uterus and vagina in female) are supplied with blood through the urogenital and umbilical arteries, and urethral branch, as well as the cranial and ventral vesical arteries to the bladder.     

Value of vaginal cervical position in estimating uterine anatomy

The anatomy of the uterus is defined with the angles of the vagina, cervix and uterine corpus. Hereunder there are angles of version and flexion. The cervical position observed during the vaginal speculum examination, may give information about the uterine anatomy. In this study, we investigated the place of the cervical position in the estimation of the uterine anatomy observed during the cervical examination. We enrolled 240 patients in our study, who applied to our routine gynecology outpatient clinic with various complaints. We divided these patients into two groups according to the cervical position (anterior cervical position and posterior cervical position) observed during the speculum examination. We recorded the uterine anatomy also with the transvaginal ultrasonography. During the speculum examination, we determined that 90% of the cases with posterior fornix position were anteverted and 10% retroverted; 64.2% of the cases with anterior fornix position were anteverted and 35.8% retroverted. According to these findings, cervical position observed during the speculum examination might be useful in the estimation of the uterine anatomy regarding the angles of the version. However, the ultrasonographic examination is essential for a definitive determination of the uterine anatomy. Clin. Anat. 30:404–408, 2017. © 2017 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.     

Decreased interleukin-6 production by rat uterine artery, aorta and uterine tissues during pregnancy

Changes in size and function during pregnancy are unique tothe uterine artery. The aim of this study was to determine theinterleukin (IL)-6 activity of the uterine artery wall tissuein pregnant rats. A total of 18 Charles River white rats (ninevirgin and nine in midpregnancy) were used for the study. Bilateraluterine arteries were obtained, together with reference tissuesfrom aorta and uterus. IL-6 production was measured as opticaldensity (OD)/mg protein, in control culture media, and in thepresence of stimulants including EL-1, tumour necrosis factoralpha and lipopoly-saccharide. Polyclonal rabbit anti-humanIL-6 antibodies were used to assess IL-6 activity. In controlculture medium, uterine artery tissue samples from virgin ratsproduced significantly higher concentrations of IL-6 than samplesobtained from pregnant animals (1.8 ± 03 versus 0.9 ±0.25 OD/mg protein respectively (mean ± SE, P = 0.001).Stimulation by lipopolysaccharide increased IL-6 activity ofthe uterine artery wall. In comparison with the uterine artery,the aorta produced higher activities of IL-6, and its productionin virgin animal samples was higher than during pregnancy. Stimulantsincreased IL-6 production by both aorta and uterus tissues.Neutralization of IL-6 activity was obtained in a range of 77–93%in all samples. The lower level of IL-6 activity during pregnancyin the uterine artery and in reference tissues including aortaand uterus, may be related to acceptance of pregnancy by maternaltissues.     

应用定量组织多普勒成像技术评价家族性高胆固醇血症患者的左室功能

目的探讨定量组织多普勒成像技术(quantitative tissue velocity imaging,QTVI)在评价家族性高胆固醇血症(familial hypercholesterolemia,FH)患者左心室功能方面的临床应用价值。方法运用QTVI对24例FH患者和25例健康人心肌各节段速度曲线进行分析,测量后室间隔、侧壁、前壁、下壁、前室间隔、后壁六个壁的瓣环、基底段和中间段三个位置的心肌收缩峰值速度(Vs),左室舒张早期的运动速度(Ve)和舒张晚期的运动速度(Va),计算Ve/Va值;常规超声心动图脉冲多普勒检测二尖瓣口E、A峰流速,计算E/A值;利用M型超声测量左室射血分数(EF);计算左室Tei指数。结果FH组与对照组常规超声心动图测值均在正常范围内,差别无统计学意义;QTVI方法测得的侧壁瓣环、侧壁基底段的Ve,侧壁瓣环、侧壁基底段、后间隔基底段、后壁基底段的Ve/Va,FH组均小于对照组,差别有统计学意义(P0.05)。结论QTVI为临床检测FH患者左室功能变化提供一种无创性方法。     

Doppler flow velocity waveforms of human fetal ductus arteriosus and branch pulmonary artery.

Doppler waveforms of the human fetal ductus arteriosus and the branch pulmonary artery are distinct in their shape and might reflect fetal cardiovascular hemodynamics and vessel wall characteristics. The waveform of ductus arteriosus had two peaks, a higher one in systole and a lower one in diastole. Both peaks had slow acceleration and deceleration and looked like two narrow base isosceles triangles. This unique waveform might be due to vessel wall characteristics and an instantaneous pressure gradient between the main pulmonary artery and descending aorta. The waveform of the branch pulmonary artery showed very steep acceleration with the onset of ejection followed by steep decline, then low velocity flow during diastole. The characteristic shape of the branch pulmonary artery might be related to high vascular resistance, decreased capacitance and the earlier reflection wave of pulmonary vessels.     

Functional properties of afferent fibers supplying reproductive and other pelvic organs in pelvic nerve of female rat

1. Electrophysiological techniques were used to characterize responses of afferent fibers in pelvic nerve of adult, virgin female rats to mechanical or chemical stimulation of internal reproductive organs and to mechanical stimulation of other pelvic organs. 2. In an in vivo barbiturate-anesthetized preparation, pelvic nerve afferent fibers responded to a wide variety of mechanical stimulation applied to restricted regions of the vaginal canal, caudal uterus (body and cervix), bladder, ureter, colon, or anus. 3. Single-fiber mechanoreceptive fields were invariably confined to a single organ. Notably, responses could be evoked not only by gentle stimulation of the unit's receptive field directly on the organ itself, but also by stimulating the field indirectly with intense stimulation through the appropriate part of a contiguous organ. This innervation feature is consistent with the separability of pelvic organ functions under innocuous conditions but their confusion under noxious ones. 4. Receptive fields on the reproductive organs extended from the caudal edge of the vagina to the uterine body (including the cervix) but were most often located in the fornix (vaginocervical junction). Most units had no or low levels of spontaneous activity. Their responses to mechanical stimuli were usually slowly or moderately adapting and time-locked to the stimulus. 5. Fibers with vaginal receptive fields (including the fornix) responded best either to vaginal distension with a balloon or, more often, to a probe moving along the internal vaginal surface in a direction toward the cervix. They were observed most frequently during the proestrus stage of the rat's estrous cycle. These fibers, therefore, seem particularly suited for relaying information about stimuli that occur during mating. 6. Fibers with receptive fields on the uterine cervix and body responded best to static pressure and were observed less frequently than those with vaginal fields, regardless of estrous stage. They were, however, sensitized by hypoxia. In addition, irritation of the uterus increased the probability of observing them. These fibers, therefore, may exert their primary function during reproductive conditions different from those of virgin rats, such as parturition. 7. Response activity of most of the mechanoreceptive afferent fibers supplying reproductive organs increased as the stimulus intensity increased into the noxious range; i.e., into a range in which the stimulus momentarily produced ischemia at the stimulus site. In addition, in an in vitro preparation, pelvic nerve fibers responded in a dose-dependent manner to injections through the uterine artery of bradykinin (BRAD) as well as to other algesic chemicals, 5-hydroxytryptamine (5-HT) and KCl.(ABSTRACT TRUNCATED AT 400 WORDS)     

Instantaneous pressure-volume relationship of right atrium during isovolumic contraction in canine heart.

We studied the contraction of the right atrium in an excised cross-circulated heart preparation. Atrial volume and instantaneous atrial pressure were measured in a water-filled balloon fitted in the spontaneously contracting right atrium. The relation of instantaneous pressure to volume was analyzed by collecting pressure data from multiple isovolumic contractions with different volumes but measured at multiple identical time points in the contraction cycle. The relation was found to be quasi-linear during most of atrial systole and diastole. A linear regression formula P(t) = K(t)[V- VD(t)] was therefore fitted to the data. K(t) and VD(t) of the regression formula are the slope and the volume axis intercept in the pressure-volume plane, respectively. When the atrium beat spontaneously at a regular sinus rhythm with no inotropic intervention. K(t) increased during systole and decreased during diastole, whereas VD(t) decreased during systole and increased during diastole. The average value of K was 13 +/- 1.7 (SE) mmHg . kg . ml-1 at the end of diastole and 33 +/- 0.02 (SE) mmHg . kg . ml-1 at the end of systole. The average value of VD was 0.303 +/- 0.017 (SE) ml . kg-1 at the end of diastole and 0.212 +/- .025 (SE) ml . kg-1 at the end of systole. Enhancement of contractility with epinephrine or Ca2+ significantly increased the value of K at the end of systole, but it did not significantly affect either K at the end of diastole or VD at the end of systole and diastole.     

Role of ovarian artery-to-uterine artery anastomoses in uterine artery embolization: initial anatomic and radiologic studies

Purpose

To explore the anatomic features of normal human ovarian artery-to-uterine artery anastomoses and their impact on uterine artery embolization (UAE).

Methods

Using slice computed tomography (CT) scanning and vascular casting; models of the uterine arterial vascular network were constructed using five sets of uterus, bilateral adnexa and vagina from normal adult females. The anatomy and characteristics of these models were then studied.

Results

Both the casting specimen and the CT-reconstructed model showed the ovarian artery-to-uterine artery anastomoses clearly. Each was composed of the ovarian branch of the uterine artery and the ovarian branch of the ovarian artery. All 10 ovarian artery-to-uterine artery anastomoses were formed by direct connection between the ovarian branch of the uterine artery and the ovarian branch of the ovarian artery.

Conclusions

Thin slice CT scanning combined with vascular casting is a useful method to study the small arterial network. The anastomoses between the ovarian branch of the uterine artery and the ovarian branch of the ovarian artery were formed mainly by direct connection. The implications of the ovarian artery-to-uterine artery anastomoses on UAE are unclear; further function assessments are needed.     

Relationship of blood pressure and pump flow in an implantable centrifugal blood pump during hypertension

The purpose of this study was to evaluate the real time relationship between pump flow and pump differential pressure (D-P) during experimentally induced hypertension (HT). Two calves (80 and 68 kg) were implanted with the EVA-HEART centrifugal blood pump (SunMedical Technology Research Corp., Nagano, Japan) under general anesthesia. Blood pressure (BP) in diastole was increased to 100 mm Hg by norepinephrine to simulate HT. Pump flow, D-P, ECG, and BP were measured at pump speeds of 1,800, 2,100, and 2,300 rpm. All data were separated into systole and diastole, and pump flow during HT was compared with normotensive (NT) conditions at respective pump speeds. Diastolic BP was increased to 99.3+/-4.1 mm Hg from 66.5+/-4.4 mm Hg (p<0.01). D-P in systole was under 40 mm Hg (range of change was 10 to 40 mm Hg) even during HT. During NT, the average systolic pump flow volume was 60% of the total pump flow. However, during HT, the average systolic pump flow was 100% of total pump flow volume, although the pump flow volume in systole during HT decreased (33.1+/-5.7 vs. 25.9+/-4.0 ml/systole, p<0.01). In diastole, the average flow volume through the pump was 19.6+/-6.9 ml/diastole during NT and -2.2+/-11.1 ml/diastole during HT (p<0.01). The change in pump flow volume due to HT, in diastole, was greater than the change in pump flow in systole at each pump speed (p<0.001). This study suggests that the decrease of mean pump flow during HT is mainly due to the decrease of the diastolic pump flow and, to a much lesser degree, systolic pump flow.     

Phytoestrogens and carcinogenesis-differential effects of genistein in experimental models of normal and malignant rat endometrium

The phytoestrogen genistein was studied in normal and malignant experimental uterine models in vivo. The action of genistein on the uterus and vagina of ovariectomized DA/Han rats after 3 day oral administration (25, 50 or 100 mg/kg/BW/d) was compared to ethinyl oestradiol (0.1 mg/kg/BW/d). Effects on uterine and vaginal morphology, uterine growth and uterine gene expression were studied. A dose dependent increase of the uterine wet weight and the uterine and vaginal epithelial height, a dose dependent up-regulation of complement C3, down-regulation of clusterin mRNA expression and a stimulation of the vaginal cornification was observed after administration of genistein. Uterine gene expression and vaginal epithelium respond to genistein at doses where no significant effects on uterine wet weight were detectable. In general the vagina was more sensitive to genistein than the uterus. To analyse the action of genistein in malignant uterine tissue, the impact of a 28 d treatment with 50 mg/kg/d of genistein on the in-vivo tumour growth of RUCA I endometrial adenocarcinoma cells, following subcutaneous inoculation into syngeneic DA/Han rats, was assessed. In contrast to ethinyl oestradiol (0.1 mg/kg/BW/d), a dose of 50 mg/kg/BW/d of genistein did not affect tumour growth. Nevertheless C3 and TRPM2 mRNA expression in the tumour were both significantly stimulated by ethinyl oestradiol and genistein. In comparison to ovariectomized animals genistein up-regulated uterine wet weight and uterine dependent gene expression in tumour bearing animals. In conclusion, four independent uterine and vaginal parameters indicate genistein is a weak oestrogen receptor agonist in the uterus and vagina of female DA/Han rats, and evidence is provided for a selective oestrogen receptor modulator (SERM)-like action of genistein in normal and malignant uterine tissue.     

Three-dimensional visualization of velocity profiles in the ascending aorta in humans. A comparative study among normal aortic valves, St. Jude Medical and Starr-Edwards Silastic Ball valves

Blood velocities were recorded intraoperatively in the ascending aorta approximately 6 cm downstream of the aortic annulus in eight patients with normal aortic valves (prior to coronary bypass surgery) and in seven patients after implantation of a St. Jude Medical valve (4) or Starr-Edwards Silastic Ball valve (3) in the aortic position by means of constant temperature hot-film anemometry. The velocities were measured during 5-15 heart cycles at 41 predetermined measurement points almost evenly distributed in the cross sectional area. Velocity profiles were visualized three-dimensionally at 100 time intervals during one mean heart cycle. The standard deviation of velocities was correspondingly three-dimensionally visualized. For the patients with normal aortic valves the velocity profiles were generally flat but skew, with the highest velocity closer to the left vessel wall at the start of systole. During systole the skewness turned counter-clockwise with the highest velocities closer to the posterior, right and finally anterior vessel wall at the end of systole. In patients with an artificial heart valve in the aortic position the design of the valve was reflected on the contour of the profiles. The findings correspond well with model studies.     

The female inferior hypogastric (= pelvic) plexus: anatomical and radiological description of the plexus and its afferences—applications to pelvic surgery

AIM OF THE STUDY: We wanted to determine the anatomical features of the inferior hypogastric plexus (IHP), and the useful landmarks for a safe surgical approach during pelvic surgery. MATERIALS AND METHODS: We dissected the IHP in 22 formolized female anatomical subjects, none of which bore any stigmata of subumbilical surgery. RESULTS: The inferior hypogastric plexus (IHP) is a triangle with a posterior base and an anterior inferior top. It can be described as having three edges and three angles; its inferior edge stretches constantly from the fourth sacral root to the ureter's point of entry into the posterior layer of the broad ligament; its cranial edge is strictly parallel to the posterior edge of the hypogastric artery, along which it runs at a distance of 10 mm; its posterior (dorsal) edge is at the point of contact with the sacral roots, from which it receives its afferences. They most frequently originate from S3 or S4 (60%) and then, in one or two branches, often from S2 (40%), never from S1 and in exceptional cases from S5 (20%). There are sympathetic afferences in 30% of cases, usually through a single branch of the second, third or fourth sacral ganglion. All IHPs have at least one sacral afference and sometimes there may be up to three afferences from the same sacral root. Its dorsal cranial angle, which is superior, comes after the SHP (hypogastric nerve or presacral nerve filament); its anterior inferior angle is located exactly at the ureter's point of entry into the posterior layer of the broad ligament. This is the top of the IHP; its posterior inferior angle is located at the point of contact with the fourth sacral root. At its entrance at the base of the parametrium the pelvic ureter is the anterior, fundamental positional reference for the IHP. The vaginal efferences come out of the top of the IHP through branches leading to the bladder, the vagina and the rectum, which originate through two trunks exactly underneath the crossing point of the ureter and the uterine artery: (i) one trunk leading to the bladder runs along and underneath the ureter and divides into two groups, which are lateral and medial, trigonal. (ii) the trunk leading to the vagina runs along the inferior edge of the uterine artery. At the point of contact with the lateral edge of the vagina, it splits into two groups: anterior thin and posterior voluminous. Some of its branches perforate the posterior wall of the vagina and are distributed to the rectovaginal septum in a tooth comb pattern. The inferior branches, which emerge from the inferior edge of the IHP, reach the rectum directly. The dissection of the 22 specimens allowed us to describe three efferent plexuses: a vaginal rectal plexus, a vesical plexus and a inferior rectal plexus. So the IHP's anterior, fundamental positional reference is the pelvic ureter at the point where it enters at the base of the parametrium, then at the crossing point of the uterine artery. The ureter is the vector for vesical efferences, the uterine artery is the vector for vaginal efferences, which are thus sent into the vesicovaginal septum and the rectovaginal septum. This surgical point of reference is of vital importance in nerve sparing during the course of a simple or extended hysterectomy. Any dissection carried out underneath and outside of the ureter inevitably carries a risk of lesions to its efferent, lateral vesical or medial, rectovaginal fibres.