The abdomen
Spencer W. Beasley, John Hutson, Mark Stringer, Sebastian K. King, Warwick J. Teague in Paediatric Surgical Diagnosis, 2018
In rectal prolapse part or all of the rectum protrudes through the anal canal. Rectal prolapse may occur in association with myelomeningocele (from paresis of the pelvic floor), exstrophy of the bladder (from disturbance of the structural support of the rectum), cystic fibrosis (chronic cough with increased intra-abdominal pressure), following pelvic surgery, in chronic diarrhoea or severe malnutrition, but most often occurs without any obvious underlying cause. It tends to be seen in toddlers during the second year of life, and occurs after straining during defecation and may follow either constipation or acute diarrhoea. The prolapsed rectal mucosa has a pink/red glistening surface which, with chronic prolapse, may become congested and ulcerated. It may bleed readily on contact with nappies. Rectal mucosal prolapse rarely extends a few centimetres beyond the anal orifice; full-thickness rectal prolapse can extend much further. Usually the prolapse reduces spontaneously but occasionally it may require manual reduction. A rectal polyp can be distinguished by the demonstration of its pedunculated stalk. Rectal prolapse can be distinguished from anal prolapse of an intussusceptum in that the child is otherwise well and the prolapse causes eversion of the anal canal.
Anorectal Abscess
Laurence R. Sands, Dana R. Sands in Ambulatory Colorectal Surgery, 2008
Symptoms depend on the site of the abscess and the extent of the infection. The classic symptoms of acute suppuration—a tender erythematous swelling—often accompany perianal abscess due to its superficial location. In this case, the inflammatory mass will be present outside the anal verge and fluctuance might not be present. In the other types of anorectal abscesses that are located deep within the pelvic tissue, a mass may not be easily evident on physical examination, or it may only be palpated or visualized during a rectal exam or anoscopy (Fig. 1) (43). If present, it may be located on the upper part of the anal canal or the lower part of the rectum. Because of the location, the patient may recount a history of prolonged symptoms (pain, fever), and is more likely to have systemic symptoms such as fever and leukocytosis compared to a superficial perianal abscess. An ischiorectal abscess, if swelling and erythema are involved, will appear medially at the buttock, lateral to the anal verge (Fig. 2). A deep postanal abscess can be associated with severe rectal discomfort, pain radiating to the sacrum, coccyx, or buttocks, and may be confused for coccydynia. An intersphincteric abscess is usually associated with severe pain and frequently requires an evaluation under anesthesia (EUA). Pain associated with an anorectal abscess is often exacerbated by or appears after evacuation.
The anus and anal canal
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie in Bailey & Love's Short Practice of Surgery, 2018
As continence is dependent upon the structural and functional integrity of both the neurological pathways and the gastrointestinal tract, the risk factors for anal incontinence are many. Patients complaining of the involuntary loss of rectal contents require a comprehensive assessment of the nature and severity of symptoms; past history, especially of gastrointestinal disease, neurological conditions, obstetric events and anal surgery; and careful clinical examination (in the elderly, incontinence is often one of overflow secondary to rectal impaction, and proctitis may lead to such an irritable rectum that even the strongest sphincter is occasionally overwhelmed). A combination of history and examination will usually be diagnostic, but special investigations are then usually required to clarify the exact cause, including exclusion of an underlying malignancy, and to direct management.
Patterns in ano-rectal dose maps and the risk of late toxicity after prostate IMRT
Published in Acta Oncologica, 2019
Eva Onjukka, Claudio Fiorino, Alessandro Cicchetti, Federica Palorini, Ilaria Improta, Giovanna Gagliardi, Cesare Cozzarini, Claudio Degli Esposti, Pietro Gabriele, Riccardo Valdagni, Tiziana Rancati
Treatment data, including 3D-dose distributions, were imported into VODCA (MSS Medical Software Solutions GmbH, Switzerland) for the generation of DSMs [22] for the anal canal and rectum as a single structure, and for the anal canal and the rectum separately. The anal canal was defined as the structure extending 3 cm cranially of the anal sphincter. The rectum was defined from the anal canal to the point where the structure starts turning anteriorly. DSMs were extracted from VODCA after a review of the segmentation of the OAR. The dose map of the tubular surface of the OAR was unfolded along the posterior axis and converted into a 2D-dose map. The lateral (left-right direction) extent of the map varies with the circumference of the outline of each image slice, and corresponds to a snapshot of the anatomy at the time of the acquisition of the treatment-planning CT. Therefore, the dose map was represented both with this anatomical axis and with a relative lateral axis of 200 pixels, using linear one-dimensional interpolation (see Figure 1). This latter representation will be referred to as laterally normalized DSM (referring to the geometry, not dose).
Dose-response relationships of the sigmoid for urgency syndrome after gynecological radiotherapy
Published in Acta Oncologica, 2018
Eleftheria Alevronta, Viktor Skokic, Ulrica Wilderäng, Gail Dunberger, Fei Sjöberg, Cecilia Bull, Karin Bergmark, Rebecka Jörnsten, Gunnar Steineck
The rectum, the sigmoid colon and small intestine were delineated in the CT scans and the dose–volume histograms were exported for each patient. As we thoroughly described in a previous publication, delineation was performed manually at Karolinska University Hospital, Stockholm and at Sahlgrenska University Hospital, Gothenburg following written instructions and with the guidance of a contouring manual with illustrations [11]. The outer contour of the rectum was delineated, included filling. The rectum was extended from the anal verge to the recto-sigmoid junction. We started delineating the sigmoid colon where the rectum deviates from its midposition to where it turns cranially in the left part of the abdomen connecting to the colon descendens. For the small intestine, we delineated all visible small bowels in the pelvic cavity to the caudal part of the sacroiliac joints [11].
Statistical shape modeling of the pelvic floor to evaluate women with obstructed defecation symptoms
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Megan R. Routzong, Ghazaleh Rostaminia, Shaniel T. Bowen, Roger P. Goldberg, Steven D. Abramowitch
Rectum stability plays a critical role in the passage of stool during defecation. It is generally believed that the presence of rectocele, enterocele, or rectal intussusception can cause stool entrapment by pocketing or folding the rectum, contributing to ODS (Pescatori et al. 2007; Cavallaro et al. 2019). Our team previously described rectal folding and pocketing as rectum hypermobility using magnetic resonance (MR) defecography and pelvic floor dynamic ultrasound, establishing an association between rectal hypermobility and ODS (Rostaminia et al. 2020). In addition to providing rectal stability, a normally supported pelvic floor resists downward motion during increases in intraabdominal pressure, creating a stable backstop during defecation. The excessive descent of the pelvic floor and levator plate at rest and during Valsalva have been described as pelvic floor relaxation (Hsu et al. 2006; Rostaminia et al. 2015). These findings motivate further investigation of pelvic floor anatomy and quantification of deviations from normal structure and function.
Related Knowledge Centers
- Anal Canal
- Gastrointestinal Tract
- Levator Ani
- Sigmoid Colon
- Pelvic Floor
- Large Intestine
- Sacrum
- Pectinate Line
- Anus
- Feces