The Experts below are selected from a list of 16332 Experts worldwide ranked by ideXlab platform
Ravinder K Mittal - One of the best experts on this subject based on the ideXlab platform.
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Closure mechanism of the Anal cAnal in women: assessed by three-dimensional ultrasound imaging.
Diseases of The Colon & Rectum, 2008Co-Authors: Sungae Jung, Milena Weinstein, Debbie Den-boer, Charles W. Nager, Dolores H. Pretorius, Ravinder K MittalAbstract:PURPOSE: To describe the functional correlates of Anal cAnal anatomy using 3 dimensional ultrasound imaging. METHODS: Ten nulliparous women were studied by using a 10-cm bag of 20-mm diameter. The bag was placed along the Anal cAnal and inflated with 20 to 45 ml water, in 5-ml increments. At each volume, a three-dimensional ultrasound volume of the Anal cAnal was obtained while the subjects were at rest and squeeze. The ultrasound images were Analyzed to determine the relationship between the bag cross-sectional area and bag pressure. RESULTS: At low distension volumes, the bag is shaped like an "hourglass." The flared ends of the funnels correspond with the proximal and distal margins of the puborectalis muscle and external Anal sphincter respectively. With increasing bag volumes, the length of completely closed segment of Anal cAnal decreased. The last Anal segment to open at rest was the one surrounded by all three structures. Anal contraction resulted in reduction of the Anal cAnal cross-sectional area; the least compliant part of the Anal cAnal was the one surrounded by external Anal sphincter. CONCLUSION: The internal Anal sphincter, external Anal sphincter, and puborectalis muscle are all involved in the Anal cAnal closure function. During contraction, the external Anal sphincter is the strongest component of Anal cAnal closure mechanism.
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effects of pelvic floor muscle contraction on Anal cAnal pressure
American Journal of Physiology-gastrointestinal and Liver Physiology, 2007Co-Authors: Bikram S Padda, Sungae Jung, Charles W. Nager, Dolores H. Pretorius, Debbie Denboer, Ravinder K MittalAbstract:The role of pelvic floor muscle contraction in the genesis of Anal cAnal pressure is not clear. Recent studies have suggested that vaginal distension increases pelvic floor muscle contraction. We studied the effects of vaginal distension on Anal cAnal pressure in 15 nullipara asymptomatic women. Anal pressure, rest, and squeeze were measured using station pull-through manometry techniques with no vaginal probe, a 10-mm vaginal probe, and a 25-mm vaginal probe in place. Rest and squeeze vaginal pressures were significantly higher when measured with the 25-mm probe compared with the 10-mm probe, suggesting that vaginal distension enhances pelvic floor contraction. In the presence of the 25-mm vaginal probe, rest and squeeze Anal pressures in the proximal part of the Anal cAnal were significantly higher compared with no vaginal probe or the 10-mm vaginal probe. On the other hand, distal Anal pressures were not affected by any of the vaginal probes. Ultrasound imaging of the pelvic floor revealed that vaginal distension increased the anterior-posterior length of the puborectalis muscle. Atropine at 15 μg/kg had no influence on the rest and squeeze Anal pressures with or without vaginal distension. Our data suggest that pelvic floor contractions increase pressures in the proximal part of the Anal cAnal, which is anatomically surrounded by the puborectalis muscle. We propose that pelvic floor contraction plays an important role in the fecal continence mechanism by increasing Anal cAnal pressure.
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functional correlates of Anal cAnal anatomy puborectalis muscle and Anal cAnal pressure
The American Journal of Gastroenterology, 2006Co-Authors: N M Guaderrama, Charles W. Nager, Sonali Master, Dolores H. Pretorius, Ravinder K MittalAbstract:BACKGROUND: Resting and squeeze pressures in the Anal cAnal are thought to reflect the contributions of the internal Anal sphincter (IAS) and the external Anal sphincter (EAS) respectively. Role of the puborectalis muscle (PRM) in the genesis of Anal cAnal pressure is not known. OBJECTIVES: To determine the functional correlates of Anal cAnal anatomy. METHODS: Seventeen asymptomatic nulliparous women were studied using simultaneous 3D ultrasound images and manometry of the Anal cAnal. Ultrasound images were recorded using a transducer placed at the vaginal introitus and pressures were recorded with a side-hole manometry catheter using a station (every 5 mm) pull-through technique. Pressures were recorded at rest and during voluntary squeeze. RESULTS: Anal cAnal high pressure zone was 39 +/- 1 mm in length. The IAS, EAS, and PRM were clearly visualized in the ultrasound images. EAS was located in the distal (length 19 +/- 1 mm) and PRM in the proximal part (length 18 +/- 1 mm) of the Anal cAnal. The station pull-through technique revealed increases in pressure with voluntary squeeze in the proximal as well as distal parts of the Anal cAnal. Proximal Anal cAnal pressure, located in the PRM zone, showed greater circumferential asymmetry than the distal Anal cAnal pressure, located in the EAS zone. CONCLUSIONS: (1) PRM contributes to the squeeze pressure in the proximal part of the Anal cAnal and EAS to the distal Anal cAnal. (2) PRM squeeze-related increase in Anal cAnal pressure might be important in the Anal continence mechanism.
Runjan Chetty - One of the best experts on this subject based on the ideXlab platform.
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Tumours of the Anal cAnal
Current Diagnostic Pathology, 2006Co-Authors: S. Serra, Runjan ChettyAbstract:Summary Anal cAnal pathology, particularly infections and tumours, has recently come into prominence, mainly because of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome. This review provides a framework for diagnostic pathologists who may encounter Anal cAnal tumours. A summary of embryology, anatomy and terminology is provided by way of background. Important points of distinction between the surgical, anatomic and histologic Anal cAnal are highlighted. Squamous carcinomas and their precursor lesion, Anal intra-epithelial neoplasia, are the most common primary epithelial abnormalities seen in the Anal cAnal. In addition, there is a predilection for HIV-positive homosexual men with co-existent human papillomavirus (HPV) infection to develop squamous carcinomas. The more proximal the tumour is in the Anal cAnal, the greater the association with basaloid morphology and HPV infection. Adenocarcinomas are uncommon and may arise from the Anal transitional zone, Anal glands or fistulous tracts, which may or may not be associated with long-standing Crohn's disease. The immunohistochemical profiles and separation from morphologically similar tumours are provided in this article. In addition, the role of new molecular markers is discussed in relation to tumour behaviour and therapeutic options.
G. M. Stirrat - One of the best experts on this subject based on the ideXlab platform.
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Changes in Anal cAnal sensation after childbirth.
The British journal of surgery, 1991Co-Authors: H. Cornes, D. C. C. Bartolo, G. M. StirratAbstract:Obstetic trauma predisposes to faecal incontinence. Anal cAnal sensation is impaired in incontinent patients. To assess the effect of childbirth on Anal cAnal sensation Anal mucosal electrosensitivity was measured in 122 primiparous patients in the immediate postnatal period and in 74 at 6 months postpartum. There were 35 normal vaginal deliveries, 36 forceps deliveries, 20 ventouse extractions, ten vaginal breech deliveries and 21 caesarean sections. Sensation was impaired in the lower, mid and upper Anal cAnal immediately after delivery in those patients who had a normal vaginal delivery or a forceps delivery when compared with controls or with those delivered by caesarean section. Women who had ventouse deliveries had impaired sensation immediately after delivery in the mid Anal cAnal compared with controls and those undergoing caesarean section. By 6 months there were no differences between any group. Patients who sustained a division of the external Anal sphincter at delivery had impaired sensation which persisted in the upper Anal cAnal at 6 months.
Dolores H. Pretorius - One of the best experts on this subject based on the ideXlab platform.
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Closure mechanism of the Anal cAnal in women: assessed by three-dimensional ultrasound imaging.
Diseases of The Colon & Rectum, 2008Co-Authors: Sungae Jung, Milena Weinstein, Debbie Den-boer, Charles W. Nager, Dolores H. Pretorius, Ravinder K MittalAbstract:PURPOSE: To describe the functional correlates of Anal cAnal anatomy using 3 dimensional ultrasound imaging. METHODS: Ten nulliparous women were studied by using a 10-cm bag of 20-mm diameter. The bag was placed along the Anal cAnal and inflated with 20 to 45 ml water, in 5-ml increments. At each volume, a three-dimensional ultrasound volume of the Anal cAnal was obtained while the subjects were at rest and squeeze. The ultrasound images were Analyzed to determine the relationship between the bag cross-sectional area and bag pressure. RESULTS: At low distension volumes, the bag is shaped like an "hourglass." The flared ends of the funnels correspond with the proximal and distal margins of the puborectalis muscle and external Anal sphincter respectively. With increasing bag volumes, the length of completely closed segment of Anal cAnal decreased. The last Anal segment to open at rest was the one surrounded by all three structures. Anal contraction resulted in reduction of the Anal cAnal cross-sectional area; the least compliant part of the Anal cAnal was the one surrounded by external Anal sphincter. CONCLUSION: The internal Anal sphincter, external Anal sphincter, and puborectalis muscle are all involved in the Anal cAnal closure function. During contraction, the external Anal sphincter is the strongest component of Anal cAnal closure mechanism.
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effects of pelvic floor muscle contraction on Anal cAnal pressure
American Journal of Physiology-gastrointestinal and Liver Physiology, 2007Co-Authors: Bikram S Padda, Sungae Jung, Charles W. Nager, Dolores H. Pretorius, Debbie Denboer, Ravinder K MittalAbstract:The role of pelvic floor muscle contraction in the genesis of Anal cAnal pressure is not clear. Recent studies have suggested that vaginal distension increases pelvic floor muscle contraction. We studied the effects of vaginal distension on Anal cAnal pressure in 15 nullipara asymptomatic women. Anal pressure, rest, and squeeze were measured using station pull-through manometry techniques with no vaginal probe, a 10-mm vaginal probe, and a 25-mm vaginal probe in place. Rest and squeeze vaginal pressures were significantly higher when measured with the 25-mm probe compared with the 10-mm probe, suggesting that vaginal distension enhances pelvic floor contraction. In the presence of the 25-mm vaginal probe, rest and squeeze Anal pressures in the proximal part of the Anal cAnal were significantly higher compared with no vaginal probe or the 10-mm vaginal probe. On the other hand, distal Anal pressures were not affected by any of the vaginal probes. Ultrasound imaging of the pelvic floor revealed that vaginal distension increased the anterior-posterior length of the puborectalis muscle. Atropine at 15 μg/kg had no influence on the rest and squeeze Anal pressures with or without vaginal distension. Our data suggest that pelvic floor contractions increase pressures in the proximal part of the Anal cAnal, which is anatomically surrounded by the puborectalis muscle. We propose that pelvic floor contraction plays an important role in the fecal continence mechanism by increasing Anal cAnal pressure.
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functional correlates of Anal cAnal anatomy puborectalis muscle and Anal cAnal pressure
The American Journal of Gastroenterology, 2006Co-Authors: N M Guaderrama, Charles W. Nager, Sonali Master, Dolores H. Pretorius, Ravinder K MittalAbstract:BACKGROUND: Resting and squeeze pressures in the Anal cAnal are thought to reflect the contributions of the internal Anal sphincter (IAS) and the external Anal sphincter (EAS) respectively. Role of the puborectalis muscle (PRM) in the genesis of Anal cAnal pressure is not known. OBJECTIVES: To determine the functional correlates of Anal cAnal anatomy. METHODS: Seventeen asymptomatic nulliparous women were studied using simultaneous 3D ultrasound images and manometry of the Anal cAnal. Ultrasound images were recorded using a transducer placed at the vaginal introitus and pressures were recorded with a side-hole manometry catheter using a station (every 5 mm) pull-through technique. Pressures were recorded at rest and during voluntary squeeze. RESULTS: Anal cAnal high pressure zone was 39 +/- 1 mm in length. The IAS, EAS, and PRM were clearly visualized in the ultrasound images. EAS was located in the distal (length 19 +/- 1 mm) and PRM in the proximal part (length 18 +/- 1 mm) of the Anal cAnal. The station pull-through technique revealed increases in pressure with voluntary squeeze in the proximal as well as distal parts of the Anal cAnal. Proximal Anal cAnal pressure, located in the PRM zone, showed greater circumferential asymmetry than the distal Anal cAnal pressure, located in the EAS zone. CONCLUSIONS: (1) PRM contributes to the squeeze pressure in the proximal part of the Anal cAnal and EAS to the distal Anal cAnal. (2) PRM squeeze-related increase in Anal cAnal pressure might be important in the Anal continence mechanism.
Charles W. Nager - One of the best experts on this subject based on the ideXlab platform.
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Closure mechanism of the Anal cAnal in women: assessed by three-dimensional ultrasound imaging.
Diseases of The Colon & Rectum, 2008Co-Authors: Sungae Jung, Milena Weinstein, Debbie Den-boer, Charles W. Nager, Dolores H. Pretorius, Ravinder K MittalAbstract:PURPOSE: To describe the functional correlates of Anal cAnal anatomy using 3 dimensional ultrasound imaging. METHODS: Ten nulliparous women were studied by using a 10-cm bag of 20-mm diameter. The bag was placed along the Anal cAnal and inflated with 20 to 45 ml water, in 5-ml increments. At each volume, a three-dimensional ultrasound volume of the Anal cAnal was obtained while the subjects were at rest and squeeze. The ultrasound images were Analyzed to determine the relationship between the bag cross-sectional area and bag pressure. RESULTS: At low distension volumes, the bag is shaped like an "hourglass." The flared ends of the funnels correspond with the proximal and distal margins of the puborectalis muscle and external Anal sphincter respectively. With increasing bag volumes, the length of completely closed segment of Anal cAnal decreased. The last Anal segment to open at rest was the one surrounded by all three structures. Anal contraction resulted in reduction of the Anal cAnal cross-sectional area; the least compliant part of the Anal cAnal was the one surrounded by external Anal sphincter. CONCLUSION: The internal Anal sphincter, external Anal sphincter, and puborectalis muscle are all involved in the Anal cAnal closure function. During contraction, the external Anal sphincter is the strongest component of Anal cAnal closure mechanism.
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effects of pelvic floor muscle contraction on Anal cAnal pressure
American Journal of Physiology-gastrointestinal and Liver Physiology, 2007Co-Authors: Bikram S Padda, Sungae Jung, Charles W. Nager, Dolores H. Pretorius, Debbie Denboer, Ravinder K MittalAbstract:The role of pelvic floor muscle contraction in the genesis of Anal cAnal pressure is not clear. Recent studies have suggested that vaginal distension increases pelvic floor muscle contraction. We studied the effects of vaginal distension on Anal cAnal pressure in 15 nullipara asymptomatic women. Anal pressure, rest, and squeeze were measured using station pull-through manometry techniques with no vaginal probe, a 10-mm vaginal probe, and a 25-mm vaginal probe in place. Rest and squeeze vaginal pressures were significantly higher when measured with the 25-mm probe compared with the 10-mm probe, suggesting that vaginal distension enhances pelvic floor contraction. In the presence of the 25-mm vaginal probe, rest and squeeze Anal pressures in the proximal part of the Anal cAnal were significantly higher compared with no vaginal probe or the 10-mm vaginal probe. On the other hand, distal Anal pressures were not affected by any of the vaginal probes. Ultrasound imaging of the pelvic floor revealed that vaginal distension increased the anterior-posterior length of the puborectalis muscle. Atropine at 15 μg/kg had no influence on the rest and squeeze Anal pressures with or without vaginal distension. Our data suggest that pelvic floor contractions increase pressures in the proximal part of the Anal cAnal, which is anatomically surrounded by the puborectalis muscle. We propose that pelvic floor contraction plays an important role in the fecal continence mechanism by increasing Anal cAnal pressure.
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functional correlates of Anal cAnal anatomy puborectalis muscle and Anal cAnal pressure
The American Journal of Gastroenterology, 2006Co-Authors: N M Guaderrama, Charles W. Nager, Sonali Master, Dolores H. Pretorius, Ravinder K MittalAbstract:BACKGROUND: Resting and squeeze pressures in the Anal cAnal are thought to reflect the contributions of the internal Anal sphincter (IAS) and the external Anal sphincter (EAS) respectively. Role of the puborectalis muscle (PRM) in the genesis of Anal cAnal pressure is not known. OBJECTIVES: To determine the functional correlates of Anal cAnal anatomy. METHODS: Seventeen asymptomatic nulliparous women were studied using simultaneous 3D ultrasound images and manometry of the Anal cAnal. Ultrasound images were recorded using a transducer placed at the vaginal introitus and pressures were recorded with a side-hole manometry catheter using a station (every 5 mm) pull-through technique. Pressures were recorded at rest and during voluntary squeeze. RESULTS: Anal cAnal high pressure zone was 39 +/- 1 mm in length. The IAS, EAS, and PRM were clearly visualized in the ultrasound images. EAS was located in the distal (length 19 +/- 1 mm) and PRM in the proximal part (length 18 +/- 1 mm) of the Anal cAnal. The station pull-through technique revealed increases in pressure with voluntary squeeze in the proximal as well as distal parts of the Anal cAnal. Proximal Anal cAnal pressure, located in the PRM zone, showed greater circumferential asymmetry than the distal Anal cAnal pressure, located in the EAS zone. CONCLUSIONS: (1) PRM contributes to the squeeze pressure in the proximal part of the Anal cAnal and EAS to the distal Anal cAnal. (2) PRM squeeze-related increase in Anal cAnal pressure might be important in the Anal continence mechanism.
