Visualization of the left extraperitoneal space and spatial relationships to its related spaces by the visible human project

BACKGROUND

The major hindrance to multidetector CT imaging of the left extraperitoneal space (LES), and the detailed spatial relationships to its related spaces, is that there is no obvious density difference between them. Traditional gross anatomy and thick-slice sectional anatomy imagery are also insufficient to show the anatomic features of this narrow space in three-dimensions (3D). To overcome these obstacles, we used a new method to visualize the anatomic features of the LES and its spatial associations with related spaces, in random sections and in 3D.

METHODS

In conjunction with Mimics® and Amira® software, we used thin-slice cross-sectional images of the upper abdomen, retrieved from the Chinese and American Visible Human dataset and the Chinese Virtual Human dataset, to display anatomic features of the LES and spatial relationships of the LES to its related spaces, especially the gastric bare area. The anatomic location of the LES was presented on 3D sections reconstructed from CVH2 images and CT images.

PRINCIPAL FINDINGS

What calls for special attention of our results is the LES consists of the left sub-diaphragmatic fat space and gastric bare area. The appearance of the fat pad at the cardiac notch contributes to converting the shape of the anteroexternal surface of the LES from triangular to trapezoidal. Moreover, the LES is adjacent to the lesser omentum and the hepatic bare area in the anterointernal and right rear direction, respectively.

CONCLUSION

The LES and its related spaces were imaged in 3D using visualization technique for the first time. This technique is a promising new method for exploring detailed communication relationships among other abdominal spaces, and will promote research on the dynamic extension of abdominal diseases, such as acute pancreatitis and intra-abdominal carcinomatosis.

Septic peritonitis

Bacterial septic peritonitis is a serious condition that requires immediate treatment. The pathogenesis is complex, and the list of diagnostic differentials is extensive. The keys to successful treatment are early recognition of the condition and elimination of the causative organism. Multiple options for draining the peritoneal cavity exist, and further studies are necessary to establish specific, evidence-based guidelines. The prognosis is generally guarded in dogs and cats. Much depends on whether the patient develops concurrent sepsis, systemic inflammatory response syndrome, or multiple organ dysfunction syndrome.

Salvaging the "lost peritoneum" after ventriculoatrial shunt failures

OBJECTIVE

Placement of a ventriculoperitoneal (VP) shunt is the long-standing treatment of choice for hydrocephalus. However, in many patients with repeated distal failures, ventriculoatrial (VA) shunts are placed. Should the VA shunt fail, finding appropriate distal sites is often difficult.

MATERIALS AND METHODS

We identified six patients, over a 3-year period, in whom conversion of VA to VP shunt was successfully performed with the aid of diagnostic laparoscopy or laparotomy. There were no ensuing shunt failures during the follow-up period (mean 1.5 years).

CONCLUSION

Because of the benefits of VP over VA shunting, every effort should be made to preserve the peritoneum as the target for the distal catheter. Laparotomy/laparoscopy is useful in locating suitable peritoneal targets when converting to VP shunt after VA shunt failure, or as a final effort before VA shunt conversion.

The Time Course of Lymphatic Routes Emanating from the Peritoneal Cavity in Rats

The lymph drainage routes from the abdominal cavity in rats were observed at 3 min, 1, 2 and 4 h after India ink was administered intraperitoneally. Four systems of lymph drainage routes from the peritoneal cavity were observed. Three minutes after injection, the drainage route travelled via the intrathoracic lymph vessels located along the internal thoracic artery and returned to the anterior mediastinal lymph nodes. One hour after injection, the drainage route travelled via the lymph vessel located along the left phrenic nerve in addition to the drainage route observed at 3 min. Two and four hours after injection, in addition to the above-mentioned routes, the drainage that had travelled via the thoracic duct continued along the right side of the aorta and was also observed in the lateral lymph vessel located on the vertebra. These findings suggest that lymph or cells absorbed into the peritoneal cavity at first travel towards the anterior mediastinal lymph nodes in the thorax via the ventral lymphatic channels, and then gradually course through the dorsal lymphatic channels. These routes may serve as a route for transporting cancer cells and other cells from the peritoneal cavity.

The time course of lymph drainage from the peritoneal cavity in beagle dogs

Lymph drainage routes from the abdominal and pelvic cavities in beagle dogs were observed serially by following the time course of India ink administered intraperitoneally. Four systems of lymph drainage routes from the peritoneal cavity were observed in this study. The earliest drainage returned to the cranial mediastinal lymph nodes via the sternal lymph vessels; subsequently, the sternal lymph nodes located along the internal thoracic artery became involved. Then, a drainage route via the lymph vessel along the left vagus nerve was observed. The final drainage route flowed into the lateral lymph vessel through the thoracic duct located on the vertebra. These results show that India ink is absorbed from the peritoneal cavity, and that the lymph drainage first flows mainly towards the cranial mediastinal lymph nodes through the ventral lymphatic channels. Our serial observations suggest that, over time, the lymph drainage routes changed from the ventral abdominal to the dorsal thoracic lymphatic channels in the thorax.

Open-window laparotomy during a transperitoneal approach to the lower lumbar vertebrae: new method for reducing complications

There are numerous approaches for exploring the lower lumbar vertebrae, and the anterior transperitoneal route is one of the most popular. Like all surgical techniques, this approach has advantages and disadvantages. It provides direct access to the target tissue through a small incision, exposes the anterior portion of the vertebrae well, and permits good visualization of the major vessels, thus reducing risk of vascular injury and life-threatening hemorrhage. However, compared to the extraperitoneal route, the transperitoneal approach carries higher risks for peritoneal complications. This article describes a new practical method for creating an extraperitoneal passageway or "window" during transperitoneal approaches to the lower lumbar vertebrae. Isolation of the peritoneal cavity and its contents with this technique can reduce peri- and postoperative abdominal complications.

Midline extraperitoneal approach to upper urinary tract surgery: Anatomical basis of surgical technique

AIM

To overcome the disadvantages inherent in the standard surgical approach to the kidney, we introduced a novel surgical technique via a midline extraperitoneal approach. The surgical technique is not substantially different from that of the standard midline transperitoneal approach, except no entry is made into the peritoneal cavity. Although the peritoneum itself is extremely thin and fragile, the peritoneum together with underlying subperitoneal fascia can be dissected readily as a substantial layer, if the proper plane is dissected. Further medial mobilization of the peritoneal sac en bloc by pursuing the fusion fascia plane allows full exposure of the kidney, ureter and great vessels. This approach was adopted for consecutive 51 patients during a 10-month period in 2003. All operations, including 33 radical nephrectomies and 11 nephroureterectomies were completed successfully without significant technical difficulties and differences in operation time and estimated blood loss compared to the transperitoneal approach. No intra- or perioperative complication occurred. All patients did seem to have a much more comfortable postoperative period with minor pain and few abdominal complaint, and the clinical impression was that they resumed the physical activity and oral intake earlier than those after the transperitoneal approach (P = 0.056). There are no operation-related problems such as intra-abdominal adhesion or abdominal muscle weakness resulting in some deformity at 2-year or more follow up. This approach combines the advantages of the transperitoneal midline and extraperitoneal flank approach. Its use will undoubtedly reduce the complications inherent in the transperitoneal approach or the flank approach.

Sectional Anatomy of the Peritoneal Reflections of the Upper Abdomen in the Coronal Plane

PURPOSE

The purpose of this study was to provide practical anatomic data for the imaging diagnosis and surgical treatment of the diseases of the subphrenic spaces.

METHODS

The sectional anatomy of the subphrenic spaces on the coronal plane was investigated on serial coronal sections of the upper abdomen of 30 Chinese adult cadavers.

RESULTS

The space between the anterior margin of gastropancreatic fold and the posterior layer of hepatogastric ligament is the only direct pathway between the superior and inferior recesses of the lesser sac. That pathway can be divided into 3 types on the coronal plane. The right layer of the gastrophrenic ligament is continuous with the posterior layer of the lesser omentum, and its left layer is continuous with the right layer of the phrenosplenic ligament and the posterior layer of the gastrosplenic ligament. The gastropancreatic fold is continued to the left and right layers of the gastrophrenic ligament upwards. The bare area of the stomach is located between the left and right layers of the gastrophrenic ligament; its existing rate is 100%. The bare area of the spleen is located among the phrenosplenic ligament, gastrosplenic ligament, splenorenal ligament, and splenocolic ligament. Its greatest width exists between the two layers of the splenorenal ligament. It can be divided into the splenic hilus and splenorenal parts.

CONCLUSION

The coronal section is dominant to show the anatomic relationships of the gastrophrenic ligaments and the gastropancreatic folds, and the bare area of the stomach.

[Development of the postoperative adhesions in the small pelvic cavity]

The aim of the study was to determine the frequency and localization of the development of postoperative adhesions for different types of surgical interventions. For this purpose, 94 patients aged 16 to 47, admitted to the department of surgery of I. Zhordania Institute of Human Reproduction in 1998-2003, who underwent diagnostic and/or operative laparoscopy and had past history of laparotomic operations (one or several) have been studied. The study revealed that development of postoperative adhesions development in the small pelvic cavity takes place in 92,55%. The III- IV degree adhesions are the most frequently developed conditions (85,72%) as a result of both gynecological and non-gynecological surgeries. Postoperative adhesions developed as result of the gynecological surgeries ranked the second (69,23%).

The history of anatomy and surgery of the preperitoneal space

Preperitoneal (properitoneal) space is the space between the peritoneum and transversalis fascia. Bogros (1786-1825) described a triangular space in the iliac region between the iliac fascia, transversalis fascia, and parietal peritoneum. In the modern concept, this space lies between the peritoneum and posterior lamina of the transversalis fascia. In 1858, Retzius described the homonymous space, situated anterior and lateral to the urinary bladder (prevesical space). In 1975, Fowler reported that the preperitoneal fascia of the groin is distinct from the transversalis fascia. Preperitoneal herniorrhaphy may be subdivided into 2 approaches: transperitoneal and inguinal. We present herein the evolution of approaches to the preperitoneal space from use of the transperitoneal (or posterior) to use of the anterior preperitoneal and posterior preperitoneal approaches. As anatomic knowledge has increased, the evolution of laparoscopic surgery has paralleled that of open procedures.

The preperitoneal approach to the groin and the inferior epigastric vessels

Preperitoneal, a word coined by Nyhus in the 1960s, has been applied not only to posterior approaches that he, Stoppa, and Wantz popularized but to anterior exposures of the groin, which divide the transversalis fascia. This assumes that all give similar views of the easily cleaved space of Bogros. However, accumulated anatomical observations reveal the transversalis fascia as having not one but two layers. The inferior epigastric vessels run between rather than in the preperitoneal space, which is avascular and has its own fascia lining the peritoneum. Historical evidence shows that both the midline Cheatle-Henry and lateral Ugahary-Kugel approaches, which transect the abdominal wall, provide excellent exposure of the avascular preperitoneal space. However, neither the unilateral posterior McEvedy approach nor the anterior approach does, as only part of the musculature and fasciae are retracted. The inferior epigastric vasculature and posterior lamina transversalis fascia, which remain in situ, block the view. Unless they are disrupted or circumvented, neither of the latter approaches or subsequent repairs should be labeled preperitoneal.

Fast MRI used to evaluate the effect of abdominal belts during contraction of trunk muscles

STUDY DESIGN

This study focused on the effects that abdominal belts have on the sagittal section of the abdominal and pelvic cavity during contraction of the trunk muscles. Fast magnetic resonance imaging was used during the Valsalva maneuver by 11 healthy men.

OBJECTIVE

To evaluate the effect of an abdominal belt on the geometric changes in the sagittal section during Valsalva maneuvers.

SUMMARY OF BACKGROUND DATA

Several hypotheses about the effect of an abdominal belt have considered intraabdominal pressure, which has a hydraulic effect on the diaphragm, providing stability to the spine. However, there is little information on changes in the sagittal section of the abdominal and pelvic cavity.

METHODS

Eleven male volunteers without back problems were studied with fast magnetic resonance images. Sagittal section images of the abdominal and pelvic cavity were obtained under six conditions: without the belt at rest, at full inhalation, and at full inhalation with Valsalva, as well as with the belt at rest, at full inhalation, and at full inhalation with Valsalva.

RESULTS

When the belt was worn, the sagittal section area of the abdominal and pelvic cavity did not change, but its shape did. Also, the anteroposterior diameter of the abdominal and pelvic cavity increased at its upper part and decreased at its middle part, elevating the liver and diaphragm. Additionally, the lever arm length of the intraabdominal pressure increased significantly.

CONCLUSIONS

Fast magnetic resonance imaging quantified the effect of an abdominal belt on the abdominal geometric changes during the Valsalva maneuvers with the patient in a supine position.

A prospective radiological anatomical study of the variations of the position of the colon in the left pararenal space

Percutaneous puncture of the kidney allows direct access to the pyelocalicial cavities. The posterior approach of this retroperitoneal organ can be complicated of transcolic punctures due to the postrenal position of the colon. A prospective radiological anatomical study of the relationship between the left kidney and the descending colon was undertaken. One hundred computed tomograms of adult subjects were obtained from which the anatomy of the left perirenal area was determined: the descending colon is more frequently behind the kidney in the young females. Two main factors determinants of this situation are: 1) colon ontogenesis in relation to the attachment of the primitive mesocolon, permitting a 'fixed' left colon, or 'moving' left colon at the end of a long mesocolon, allowing it to pass behind the kidney; 2) a mechanical factor whereby the accumulation of perirenal fat with increasing age may be a limiting factor in lateral displacement of the colon.

Genetic evidence for obesity loci involved in the regulation of body fat distribution in obese type 2 diabetes rat, OLETF

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese type 2 diabetes in human. Obesity is essential for the onset of type 2 diabetes in this rat. Our present investigation was designed to identify quantitative trait loci (QTLs) contributing to obesity by performing a whole-genome search using 214 F(2) intercross progeny between OLETF and F344 rats. We have identified six QTLs responsible for adiposity indices of fat pads on rat chromosomes 2 (Obs1 for mesenteric fat), 4 (Obs2 for retroperitoneal fat), 8 (Obs3 for mesenteric fat), 9 (Obs4 for retroperitoneal fat), and 14 (Obs5 and Obs6 for retroperitoneal fat), demonstrating that the adiposity indices of individual fat pads were under the control of different genes. As expected, the OLETF allele corresponds to increased adiposity indices for all QTLs, except for Obs3, in which the F344 allele leads to an increase in the index.

Complications of laparoscopic and retroperitoneoscopic adrenalectomies in 370 cases in Japan: a multi-institutional study

A total of 370 laparoscopic adrenalectomies, including 311 transperitoneal (TP) and 59 retroperitoneal (RP) approaches, were performed in nine urologic centers, where the laparoscopic adrenalectomy was first begun independently in Japan, and their affiliated hospitals between January 1992 and September 1996. The clinical diagnoses of those 370 adrenal diseases were primary aldosteronism in 155 patients, Cushing's syndrome in 61. preclinical Cushing's syndrome in 21. pheochromocytoma in 16, nonfunctioning adenoma in 87, complicated cyst in ten, myelolipoma in nine, adrenal cancer in four and other diagnoses in eight (table 1). There was no mortality in this series. Intraoperative complication rate was 33/370 (9%) in total: 26/311(8%) in the TP procedures and 7/59 (12%) in the RP procedures (table 11). Postoperative complication rate was 24/370 (6%) in total: 22/311 (7%) in the TP procedures and 2/59 (3%) in the RP ones (table 111). Conversion rates to open surgery in total, in the TP and in the RP procedures were 13/370 (3.5%), 10/311 (3.2%) and 3/59 (5.1 %). respectively (table IV). Although the RP procedure has a lower morbidity rate compared to the TP procedure, more skill is required to overcome the drawback of the narrow working space and fewer anatomical landmarks.

Laparoscopic adrenalectomy: lateral transabdominal approach vs posterior retroperitoneal approach

Laparoscopic adrenalectomy has been used to remove a wide variety of adrenal neoplasms. Although several laparoscopic approaches to the adrenal gland have been described, the lateral transabdominal approach has several advantages when compared with other approaches for laparoscopic adrenalectomy. From October 1995 to July 1999, we performed laparoscopic adrenalectomies on 16 patients, including eight posterior retroperitoneal approaches and eight lateral transabdominal approaches. Sixteen patients, ranging in age from 23 to 69 years, were treated for the following conditions: non-functioning adenoma, four patients; aldosteronoma, seven patients; pheochromocytoma, three patients; Cushing's adenoma, two patients. The average tumor size was 2.5 +/- 0.5 cm (1.8-3.0 cm, median 2.4 cm) in the lateral transabdominal approach, 1.2 +/- 0.8 cm (0.8-3.2 cm, median 1.75 cm) in the posterior retroperitoneal approach. Average operative time of lateral transabdominal approach was significantly shorter than that of the posterior retroperitoneal approaches (mean 129 min vs 269 min, P = 0.0005). Conversion to laparotomy was required in one patient in the posterior approach. Postoperative complication occurred in one pneumothorax in the lateral transabdominal approach and two subcutaneous emphysemas in the posterior retroperitoneal approach. There was no statistical difference in blood loss during the operation in the two groups. There was no mortality in either group. The lateral transabdominal approach is a safe and efficient technique for the removal of the adrenal neoplasms. Compared with other approaches, this technique has a wider working space and also good exposure for removing the adrenal gland.

[An MRI study of the normal pelvis in the immediate postpartum period]

PURPOSE

To describe the MR findings of the pelvis in the early post-partum period, after vaginal delivery or cesarean section.

MATERIALS AND METHODS

Fifteen asymptomatic patients were imaged using a 1.5 Tesla MR unit between 1 and 7 days following delivery. Eight patients had a vaginal delivery, and seven patients had a cesarean section.

RESULTS

The following items were evaluated: uterus size, architecture, and contents; uterine and abdominal wall scars; parametrium; peritoneal cavity; ovarian veins.

CONCLUSION

MRI provided a good evaluation of the pelvic changes related to pregnancy and delivery. Knowledge of the normal findings should improve diagnosis of early post-partum complications.

[Cross-section anatomy of the subphrenic spaces]

The cross-section anatomy of the subphrenic spaces were investigated in 20 Chinese cadavers. On the horizontal sections, the subphrenic spaces consist of the perihepatic and perisplenic spaces. The fissure for ligamentum venosum was separated into two parts by the lesser omentum, the anterior part communicates with gastrohepatic recess, the posterior is the superior recess of the omental bursa into which the caudate lobe of the liver projected. The bare area of the stomach encroaches upon the posterior surface of the gastric fundus between the right and left layers of the gastrophrenic ligament and lies between the superior and splenic recesses of the omental bursa. Left subphrenic retroperitoneal space is between the bare area of the stomach and the diaphragm.

A combined electron microscopic investigation of the peritoneal mesothelium in the rat

Visceral and parietal peritoneum of adult Wistar rats was studied by means of transmission and scanning electron microscopy. The structure of the peritoneum follows a general plan: mesothelium, basal lamina, and submesothelial connective tissue layer. Two basic types of mesothelial cells are described: flat and high (cubic), as well as transitional forms. A regularity of distribution of these cells in the visceral and parietal peritoneal sheets, and in the cover of individual organs and regions is described. A functional characterization of the different types of mesothelial cells is attempted, based on the differences of their cytoplasmic organization. The involvement of the mesothelium in the homeostasis in the peritoneal cavity is discussed.

Anatomic CT demonstration of the peritoneal spaces, ligaments, and mesenteries: normal and pathologic processes

Computed tomography (CT) has become increasingly useful in the detection of intraabdominal disease. Owing to the widespread use of CT, it is essential that radiologists have a thorough understanding of the peritoneal spaces and the ligaments and mesenteries that form their boundaries. The majority of ligaments and mesenteries in the abdomen are formed from remnants of the ventral and dorsal mesenteries, which suspend the primitive gut. Unlike the abdominal ligaments, the pelvic ligaments are mainly formed by reflections of peritoneum over the pelvic organs or structures. The mesenteries and ligaments form the boundaries of the peritoneal spaces; this knowledge aids in localizing fluid collections, allowing the differential diagnosis to be narrowed. The ability to localize fluid collections accurately is also important if percutaneous or surgical drainage is to be performed. In addition, neoplasms can be more accurately staged when the pathway of spread through adjacent ligaments and mesenteries is understood.

MR imaging of the peritoneum and abdominal wall

Knowledge of the peritoneal cavity and the peritoneal folds that subdivide it is useful in evaluating for the presence and spread of disease processes that affect the peritoneum. Many disease processes of the peritoneum and abdominal wall are well evaluated with MR imaging, especially as MR techniques improve. In some cases, information is obtained that is not available with other imaging techniques.

Extraperitoneal endoscopic access to the pelvic regions via a suprapubic route

Transperitoneal endoscopic access for operations on the extraperitoneal pelvic regions exposes the patient to greater complications compared with the traditional surgical technique and increases the risk of operative morbidity. Access can be gained to the pelvic extraperitoneal space by suprapubic puncture, positioning the needle by insufflation in a midline position 1 cm above the pubis between the linea alba and the vesicoumbilical fibrous septum.

The topography of the thoracic and abdominal organs of the Nile crocodile (Crocodylus niloticus)

The pleural cavity of the Nile crocodile is divided into two separate cavities by means of a complete mediastinum. The pleural cavity contains the lungs, while the heart is situated in its own cavity, the pericardial cavity. The pleural cavity is separated from the hepatic coelom, which contains the liver, by the post-pulmonary membrane. The hepatic coelom is separated from the peritoneal cavity by the post-hepatic membrane. The peritoneal cavity contains the abdominal organs.

Morpho-physiological function and role of omental milky spots as omentum-associated lymphoid tissue (OALT) in the peritoneal cavity

The morpho-physiological function and role of milky spots in the greater omentum are reviewed. These milky spots are composed of cellular aggregations of mesenchymal cells, mainly macrophages and lymphocytes, surrounding capillary convolutions termed omental glomeruli. Initial lymphatics of the omentum begin at the milky spots and drain into lymph collectors. The lymphatic capillaries in the omental milky spots take part in the absorption of various substances from the peritoneal cavity. Omental milky spots probably act as the first line of defense in the peritoneal cavity and therefore are immunologically important. In human infants, most of the cells in these milky spots are macrophages (49%); less common are B lymphocytes (29%) and T lymphocytes (12%). Whereas macrophages form clusters near the peritoneal surface of the milky spots and are oriented toward the peritoneal cavity for migration, clusters of B and T lymphocytes are typically found in periarteriolar locations within the milky spots. This cell zonation facilitates phagocytosis and processing of circulating antigens and foreign bodies which emanate from the peritoneal cavity. During inflammation, the number and size of omental milky spots dramatically increase, and some develop germinal centers within the lymphatic follicles and produce antibodies. During intraperitoneal immunotherapy, the omental milky spots and their cellular elements may be activated by intraperitoneal administration of biological response modifiers, and thereby represent an important immunoregulatory system for the peritoneal cavity. Omental milky spots are also closely linked to the dissemination of cancer cells. Thus, intraperitoneally inoculated experimental tumor cells selectively invade the milky spots and proliferate there to form tumor nodules. This occurrence is relevant to clinical practice where nodular metastases to the omentum are common. Omental milky spots are analogous to regional lymph nodes and as such are the omentum-associated lymphoid tissues and participate in intraperitoneal immune reactions.

Rectal and colonic injury in the llama. Anatomic considerations and surgical management in four llamas

Transrectal palpation in llamas can result in iatrogenic rectal and colonic injury. The purpose of this report is to define the caudal extent of the peritoneal cavity in llamas and to describe the surgical management of rectal or colonic injuries in four llamas. Measurements were made of six adult llamas during necropsy. The mean distance from the peritoneal reflection to the anus was 3.9 +/- 0.1 cm (3.4-4.3 cm). Four llamas were examined for rectal or colonic perforations. One laceration was of partial thickness and three lacerations were of full thickness. Two of the defects were repaired by a transanal approach and two by celiotomy to facilitate removal of fecal debris and abdominal lavage. Successful repair of the rectal or colonic tears was achieved in all four llamas. Wound infection and incisional hernia occurred in both llamas that underwent celiotomy. Two llamas died 3 and 18 months later, and two llamas have survived 2 years. Rectal tears in llamas are accompanied by a high risk of peritoneal contamination, and primary closure is recommended. If fecal contamination of the abdomen has occurred, celiotomy is indicated to allow mechanical removal of fecal debris and peritoneal lavage.

Peritoneal reflections of left perihepatic region: radiologic-anatomic study

To clarify the anatomy of the peritoneal reflections of the left perihepatic region, the authors examined 95 cadavers. Thirty-eight were studied radiographically, 37 with sagittal dissection, and 20 with transverse dissection. In over 80% of the cadavers, the left triangular ligament of the liver separated the left suprahepatic space into anterior and posterior sections. The lesser omentum extended to the diaphragm, where its anterior layer reflected and continued as the posterior layer of the left triangular ligament. Thus, the posterior left suprahepatic space and the lesser sac were clearly separated by the lesser omentum and the stomach and over-lapped each other in three dimensions. The posterior left suprahepatic space was located anterosuperior to the lesser sac and in turn was continuous with the gastrohepatic space inferiorly. Carefully researched diagrams of both the midline sagittal and left parasagittal perihepatic spaces were developed. This information has clinical value when the radiologist is called on to drain a left perihepatic abscess.

Improved technique for establishing pneumoperitoneum for laparoscopy

The establishment of a pneumoperitoneum is essential for laparoscopy. Anatomical features of the umbilicus can be used to reduce associated complications and improve the ease of creating a pneumoperitoneum.

A model of the peritoneal cavity for use in internal dosimetry

Several therapeutic and diagnostic techniques involve injection of radioactive material into the peritoneal cavity. Estimation of the radiation dose to the surface of the peritoneum or to surrounding organs is hampered by the lack of a suitable source region in the phantom commonly used for such calculations. We have modified the Fisher-Snyder phantom to include a region representing the peritoneal cavity which may be employed to estimate such radiation doses. A geometric model is described which is coordinated with the existing organ regions in the phantom. Specific absorbed fractions (derived by Monte Carlo techniques) for photon emissions originating within the cavity are listed. Photon S-values for several radionuclides which have been administered intraperitoneally are shown. Dose conversion factors for electrons irradiating the peritoneal cavity wall, from either a thin plane or volume source of activity within the cavity, are also given for several nuclides.

[Echographic anatomy of the greater peritoneal cavity and its recesses]

The peritoneum of the great abdominal cavity and its recesses are a blind radiographical area which can however be easily outlined by US when it contains fluid. The anatomical study of these usually virtual cavities represents the purpose of this paper. The natural contrast of the peritoneal fluid as amplified by the mechanical effect produced by an adequate amount of fluid, allows a clear visualization of the anatomy of various peritoneal structures in either upper (subphrenic, subhepatic, lesser sac, etc.) or lower (pelvic) areas. The sovramesocolic and the infracolic compartments are in communication through the two external paracolic gutters which are the main passageways for the fluids between upper and lower compartments. In fact, peritoneal fluids are in constant movement due to different factors, such as gravity, statics, which causes the peritoneal fluids to flow into the lowest part of the peritoneal cavity, and hydrostatic pressure. Pressure differences are thought to convey fluids from various sites of the abdomen into different areas. In the lower abdomen, pressure is 3 times as much as in the upper abdomen, which causes the fluids to move into the subhepatic and subphrenic regions. The redistribution of fluids can be influenced by particular anatomical causes. The phrenicocolic ligament, eg, is a barrier to the advancing of fluids along the left paracolic gutter, which makes the right paracolic gutter the main passageway for the fluids. This pattern explains why abscesses are more frequent in the right than in the upper left abdominal regions. Another example is the tiny Winslow opening, which does not allow inflammatory material to pass into the lesser sac in case of inflammatory processes of the great peritoneal cavity and vice versa. Moreover, pointing out fluid collections and abscesses is important, since an early diagnosis and a topographic map are essential in order to plan treatment.

Light and electron microscope observations of the lymphatic drainage units of the peritoneal cavity of rodents

Fluid, particles, and cells are taken up from the peritoneal cavity by lymphatic drainage units, which, in the mouse and rat, are located along the peritoneal surface of the muscular portion of the diaphragm. The drainage units are composed of three specifically differentiated components: a lymphatic lacuna, a covering of lacunar mesothelium, and intervening submesothelial connective tissue. The units are drained by connecting lymphatic vessels that cross the diaphragm to empty into collecting lymphatic vessels running along the pleural surface of the diaphragm. The collecting lymphatics empty into parasternal lymphatic trunks. In this report, we briefly review critical features of the drainage apparatus and describe new observations, summarized below, about their structure. Around the rim of stomata, the mesothelial openings that lead into the lymphatic lacunae, plasma membranes of lacunar mesothelial cells and of lacunar endothelial cells abut but are not linked to one another by recognizable junctional specializations. Lacunar endothelial cells often extend valve-like processes that bridge the distal end of the channel beneath the stoma. The configuration of the endothelial processes may be complex. Occasionally, processes from fibroblasts in the submesothelial connective tissue adjacent to stomata make contact with the interstitial surface of lacunar endothelial cells. A discontinuous elastic layer in the submesothelial connective tissue spans the roof of each lacuna. Connecting and collecting lymphatics, which drain lymphatic lacunae, possess endothelial valves. Possible functions for each of these newly described structural features are discussed.

Intraperitoneal paravesical spaces: CT delineation with US correlation

The urinary bladder, obliterated umbilical arteries, and inferior epigastric vessels located within the extraperitoneal space of the anterior abdominal wall indent the anterior parietal peritoneum, forming intraperitoneal paravesical fossae. These are the supravesical space and the medial and lateral inguinal fossae. More posteriorly, the peritoneum covering the bladder is reflected onto the rectum to form the rectovesical space, which is divided by the uterus into an anterior vesicouterine recess and a posterior rectouterine pouch, or cul-de-sac. The cul-de-sac is continuous with the pararectal and ovarian fossae and is bounded posterolaterally by the rectouterine (sacrogenital) folds. These peritoneal compartments form a large potential space for the accumulation of ascites and are separated from the equally large extraperitoneal paravesical spaces by only a thin layer of peritoneum or peritoneum and umbilicovesical fascia. The computed tomographic scans of 100 patients with ascites were reviewed, with particular attention to the differentiation between intraperitoneal and extraperitoneal paravesical collections. The scans of intraperitoneal collections were found to have certain characteristic appearances, including inferior displacement of the distended urinary bladder, visualization of the umbilical folds, and preservation of the preperitoneal fat.

Extraperitoneal paravesical spaces: CT delineation with US correlation

The extraperitoneal space around the urinary bladder is lamellate, just like the retroperitoneal space around the kidneys. The bladder, urachus, and obliterated umbilical arteries lie within the perivesical space, surrounded by umbilicovesical fascia, analogous to the perinephric space within the renal fascia. A much larger prevesical space, analogous to the anterior pararenal space, lies anterior and lateral to the umbilicovesical fascia. Posterior to the urinary bladder, the lower uterine segment or seminal vesicles lie within the perivesical space, rather than in a separate compartment, corresponding to the posterior pararenal space. The cul-de-sac, and the inferolateral extension of its peritoneal layers as the rectovaginal or rectovesical septum, separate the posterior perivesical space from the rectum. The sectional anatomy of these spaces, and particularly their computed tomographic and ultrasound appearances, were noted in normal anatomic sections, patients with extraperitoneal fluid collections, and a cadaver into which fluid was injected.

Structure and function of ciliated peritoneal funnels in the toad kidney (Bufo marinus)

Scanning electron microscopy revealed 600-800 ciliated peritoneal funnels opening onto the ventral surface of each kidney in Bufo marinus. The size and configuration of funnel apertures vary greatly, but individuals course beneath the kidney surface before opening into peritubular blood vessels. Injections of India ink into the peritoneal cavity demonstrate that cilia lining the peritoneal funnels create a current carrying peritoneal fluid into the renal vasculature. Clearance of fluid by the funnels was dependent on pressure in the peritubular vessels, and was increased by arginine vasotocin. Ciliated peritoneal funnels may provide an important route for return of lymphatic fluid from the peritoneal cavity to the vasculature.

The avian ovary is an open organ. A study of the lacunar system

After an intraperitoneal injection of diluted yolk in female quails, young chicks or chick embryos (killed with minimal loss of blood), the absorption of a considerable quantity of yolk granules by the ovarian medullary lacunae can be demonstrated. This can be confirmed by the i.p. injection of killed Hela cells. From our investigation it may be concluded that the avian ovary, by the progressive expansion of its medullary lacunae, develops into a contractile sac-like structure with small openings (communicating with the peritoneal cavity) on its dorsal side. The lacunar system seems to function as an expansion room for the enlarging follicles (also the large pediculated follicles) and intervenes in follicle stalk formation. The relatively rapid uptake by means of an ovarian pumping mechanism of particles and fluid from the peritoneal cavity into the lacunae, suggests also that the latter play a role as diffusion chambers in the supply of nutritious substances to and elimination of wastes from the follicles.

[Fossae, recesses and culs-de-sac in the pelvic peritoneum of women (author's transl)]

The pelvic peritoneum in women is peculiarly irregular because of the numerous folds, fossae, recesses and culs-de-sac that exist in it. Blood and purulent serous fluids occur in the abdomino-pelvic cavity and stagnate in these sites. Since they are particularly to be found around the adnexae they can give rise to secondary infection occurring as a result of primary adnexal infection. Furthermore, when serous fluid is regurgitated into the tubo-ovarian hollow through the abdominal os of the tube and into the pertoneum around the ovary, adhesions and endometrial deposits occurring in this area can be explained. Each one of these structures should be systematically explored, particularly when hystero-salpingographies and laparoscopies are being carried out. Furthermore, they should be cleaned out very meticulously after all conservative surgery to prevent the formation of adhesions.

[Anatomical basis of abdominal cavity radiology (author's transl)]

The interpretation of the blank abdominal roentgenogram is made easier by the knowledge of radiological aspects of limits between peritoneal and retroperitoneal compartments. This knowledge rests on the images, often faintly contrasted, provided by ligaments, mesotheria, fascias and boundary muscles defined by opposition to the fatty layers that frequently stress their contours. In this work, we have defined the inferior (pelvis) and lateral (paracolic sinuses) contours of the abdominal cavity, some singularities of the compartments above and below the mesocolon and also mesenteric connexions. The importance of these structures for differential diagnosis of fluid or gas collections and abscesses (origin, location, propagation) is illustrated. The normal and pathological radiological aspects of the three retroperitoneal compartments (perirenal, pararenal anterior and posterior) and their projection area on the film were demonstrated. As the radiological demonstration of all these structures depends on the conditions of the investigation, we have tried with a material comprising 300 cases, to define the technical conditions and plan of observation that appear most favorable.