RECTUM AND ANAL CANAL

Surgical Endoscopy and Other Interventional Techniques, 2007

Background: Demonstrate precisely the anatomic configuration of the anal canal and the length and thickness of the anal sphincters using three-dimensional (3-D) anorectal ultra-sonography in both genders. Methods: Twelve normal volunteer males and 14 females, with a mean age of 52.4 and 50.3 years, respectively, were prospectively enrolled in this study. All individuals from both groups were submitted to anorectal ultra-sonography. The anal canal was analyzed, measuring the length and thickness of the external anal sphincter (EAE), internal anal sphincter (IAS), puborectalis muscle (PR) and the gap (distance from the anterior EAS to the anorectal junction) in the midline longitudinal (ML) and transverse (MT) planes, and the results were compared between quadrants and genders. Results: The distribution of sphincter muscles is asymmetric in both genders. The anterior upper anal canal is an extension of the rectal wall with all layers clearly identified. The anterior IAS is formed in the distal upper anal canal and is significantly shorter in female than in male in all quadrants. The anterior IAS length is shorter than the posterior and lateral in both genders. The anterior EAS length is significantly shorter (2.2 cm) and the gap is longer (1.2 cm) in female than in male (3.4 cm) (0.7 cm) (p < 0.05), respectively. The posterior and lateral EAS-PR is significant longer in males (3.6 cm) (3.9 cm) than in females (3.2 cm) (3.5 cm) (p < 0.05), respectively. The lateral EAS-PR is significant longer than the posterior part in both genders. The anterior IAS is significantly thicker in males (0.19 cm) than in females (0.12 cm) (p = 0.04). Conclusion: 3-D anal endosonography enabled measurement of the different anatomical structures of the anal canal and demonstrated its asymmetrical configuration. The shorter anterior EAS and IAS associated with a longer gap could justify the higher incidence of pelvic floor dysfunction in females, especially fecal incontinence and anorectocele with rectal intussusception.

2012

Purpose. This report describes the advantages of 3D anal endosonography in depicting the normal anatomy of the anal canal in relation to sex and age. Materials and methods. A retrospective study was performed of 85 patients, 33 men and 52 women, previously examined with 3D anal ultrasound (US) for clinically suspected anorectal disease but found to be negative. The examinations were performed with a Bruel and Kjaer US system with a 2050 transducer, scanning from the anorectal junction to the subcutaneous portion of the external anal sphincter (EAS). The 3D reconstructions provided an estimation of sphincter length in the anterior and posterior planes, and axial 2D images enabled calculation of the thickness of the internal anal sphincter (IAS) and EAS in the anterior, posterior and lateral transverse planes. Results. Distribution of the sphincter complex is asymmetric in both sexes: the EAS and IAS are significantly shorter in females, especially in the anterior longitudinal plane (p=0.005 and p<0.001, respectively). EAS and IAS thickness increases with age, especially the lateral IAS (R 2 =0.37, p<0.001) and the posterior EAS (R 2 =0.29, p=0.01). Conclusions. A good knowledge of anal-canal anatomy is essential to detect sphincter abnormalities when assessing pelvic floor dysfunction. Keywords 3D anal endosonography • Anal sphincter • Anal canal anatomy Riassunto Obiettivo. Scopo del presente lavoro è stato documentare la rappresentazione anatomica normale del canale anale attraverso l'ultrasonografia (US) endoanale 3D, in relazione al sesso e all'età. Materiali e metodi. In uno studio retrospettivo sono stati selezionati 85 soggetti, di cui 33 maschi e 52 femmine, sottoposti precedentemente ad US endoanale 3D per sospetto clinico di patologia dell'ano-retto distale ma risultati essere tutti negativi all'esame ultrasonografico. Gli esami sono stati eseguiti con apparecchio dedicato Bruel e Kjaer, con trasduttore tipo 2050 e scansioni dalla giunzione ano-rettale alla porzione più superficiale dello sfintere anale esterno (SAE). Nell'immediato postprocessing sono stati stimati la lunghezza degli sfinteri nei piani anteriore e posteriore e lo spessore anteriore, laterale e posteriore dello sfintere anale interno (SAI) e del SAE. Risultati. La distribuzione della muscolatura del canale anale risulta asimmetrica in entrambi i sessi: la lunghezza di SAI e SAE è significativamente più breve nelle donne, specie lungo il piano longitudinale mediano anteriore (p=0,005 e p<0,001, rispettivamente). Inoltre, lo spessore di entrambi gli sfinteri presenta una tendenza all'accrescimento proporzionale all'età del paziente, soprattutto nella porzione laterale per il SAI (R 2 =0,37, p<0,001) e posteriore per il SAE (R 2 =0,29, p=0,01). Conclusioni. La conoscenza precisa delle componenti anatomiche muscolo-legamentose del canale anale è alla ABDOMINAL RADIOLOGY RADIOLOGIA ADDOMINALE

Diseases of the Colon &amp; Rectum, 1994

World Journal of Surgery, 2000

Endosonography has evolved into an effective tool for the accurate preoperative assessment of anorectal pathology, from idiopathic anal pain to malignancy. The published data suggest that endosonography is currently the best method for assessing the structural integrity of the anal sphincter and for staging rectal cancer. The development of new treatment modalities for rectal cancer, including local excision, preoperative radiotherapy, and total mesorectal excision, has increased the importance of accurate preoperative staging to allow the optimum treatment planning. However, there is little information about the impact of endosonographic findings on clinical decision making. Education, training, and quality control in the use of endosonography also require further work. This article aims to evaluate the usefulness and limitations of this technique in clinical practice.

Cells Tissues Organs, 1990

new concept of the anatomy of the anal sphincter mechanism and the physiology of defecation; X. Anorectal sinus and band: anatomic nature and surgical significance. Dis Colon Rectum 1980;23:170-179. A study, comprising dissection and microscopic examination of the pectinate area with special consideration to anal glands, was performed in 29 cadavers varying from fully mature neonatal deaths to 52 years of age. At the junction of the anal canal proper with the rectal neck, an "anorectal sinus" (a submucosal anal circumferential depression) was identified in 18 specimens; in 6 specimens, the anorectal sinus was replaced by a fibroepithelial band ("anorectal band"); in 5 specimens, the anorectal sinus was absent, and in 3 of the 5 specimens only scattered epithelial cells ("epithelial debris" of the anorectal sinus) were detected. T h e s e findings suggest that the anorectal sinus is an embryonic vestige which results from hindgut "invagination" by the proctodeum. Its persistence or partial obliteration w o u l d result in the formation of tubular structures which are considered by investigators as anal glands. The sinus may be completely obliterated or may leave b e h i n d a submucosal "anorectal band" or scattered "epithelial debris." Evidence in favor of this new concept is put forward. The role of anoreetal sinus, anorectal band, and epithelial debris in the genesis of some idiopathic anal lesions is discussed. [

International journal of colorectal disease, 2003

The double-stapled ileoanal reservoir (DSIAR) has become a preferred method for ileal pouch anal anastomosis in restorative proctocolectomy. This investigation assessed the relative ratio of epithelial tissue types within the anal transition zone after a DSIAR and reviewed functional physiological differences. All 138 patients who underwent restorative proctocolectomy with a DSIAR for mucosal ulcerative colitis were stratified into two groups according to histological evidence of epithelium types in the distal excised rectal donut. In group I a squamous or a squamous mixed with columnar epithelium was present (n=40) whereas in group II only columnar epithelium was seen (n=98). Anal physiological parameters were measured by anal manometry preoperatively, prior to ileostomy closure, and 1 year after surgery. None of the preoperative resting and squeeze pressure parameters showed a significant difference between the two groups. Postoperative mean and maximal resting pressures were sign...

Pediatric Surgery International, 1993

Eleven fetuses and 9 newborns were examined for sensory innervation of the anorectal area. The specimens were obtained immediately after death and were stained by the modified Gross silver impregnation method and examined with a light microscope. The perianal skin and rectal mucosa did not differ in either group. The anal canals of the fetuses had numerous thin, singly-and doubly-branched nerve endings with 1.0 to 1.5 gm axonal diameters. Paccinian-type lamellated corpuscles were few and contained 3-5 flbroblastic lamellae and had a diameter of 70-100 gin. The newborn group had more prominent subepithelial free nerve endings with 2.0 to 2.5-gin axonal diameters, mostly myelinated and with numerous Paccinian corpuscles with 8-10 lamellae and diameters of 100-150 gm. Globular endings were fewer and smaller in the fetal group. Muscle spindles were seen embedded in the external sphincter muscle bundles of both groups. We conclude that this pattern of sensory nerve endings indicates a time-dependent developmental process in the human anal canal.

2021

A persistent anal membrane is a rare remnant of the foetal proctodaeum which has been rarely reported in literature. It is a low anorectal malformation. Due to its rarity and associated normally located anal opening it is often detected late in neonate. Sometimes, such membranes persist through childhood and these children present with constipation. Here, we present two cases of anal membrane at two age groups, one in a neonate and the other in a toddler with constipation.

WORLD JOURNAL OF …, 2006

To investigate whether the degree of rectal distension could defi ne the rectum functions as a conduit or reservoir.

Diseases of the Colon & Rectum, 1993