Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Anal perianal imaging part 1 CT MRI anatomy Dr Ahmed Esawy

4,948 views

Published on

Anal perianal imaging part 1 ct mri anatomy dr ahmed esawy
ANAL ,PERIANAL IMAGING
(endovaginal ultrasound endoanal ultrasound
perineal ultrasound
MRI)
FOR ANAL ,PERIANAL DISEASE3/ Image reconstruction and processing artifacts
• ANAL ANATOMY
• ANAL PERIANAL FISTULA
• ANAL TEARS (OBSTETRIC)
• FAECAL INCONTINENCE
• OTHER DISEASES
• NATOMY ANORECTAL ANATOMY :
• Anal Sphincter:
• internal sphincter
• external sphincter
• Puborectalis muscle and levator ani
• Sub cutaneous perianal fistula
• Sub mucous perianal fistula
• Low anal perianal fistula
• High anal perianal fistula
• Pelvi rectal perianal fistula
• Simple fistulography
• Perianal fistulography
• Endosonography Perianal fistula
• A. A superficial fistula.
• B. An intersphincteric fistula.
• C. A transsphincteric fistula.
• D. A suprasphincteric fistula.
• E. An extrasphincteric fistula.

Published in: Health & Medicine
  • Check the source ⇒ www.WritePaper.info ⇐ This site is really helped me out gave me relief from headaches. Good luck!
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • There is a useful site for you that will help you to write a perfect and valuable essay and so on. Check out, please ⇒ www.HelpWriting.net ⇐
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Very nice! Tnx alot!
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Anal perianal imaging part 1 CT MRI anatomy Dr Ahmed Esawy

  1. 1. Dr Ahmed Esawy
  2. 2. Dr Ahmed Esawy ANAL PERIANAL IMAGING Dr. Ahmed Esawy MBBS M.Sc MD
  3. 3. Dr Ahmed Esawy ANAL ,PERIANAL IMAGING (endovaginal ultrasound endoanal ultrasound perineal ultrasound MRI) FOR ANAL ,PERIANAL DISEASE
  4. 4. Dr Ahmed Esawy HOME MASSEGE • ANAL ANATOMY • ANAL PERIANAL FISTULA • ANAL TEARS (OBSTETRIC) • FAECAL INCONTINENCE • OTHER DISEASES
  5. 5. Dr Ahmed Esawy NATOMY ANORECTAL ANATOMY : Anal Sphincter: internal sphincter external sphincter Puborectalis muscle and levator ani
  6. 6. Dr Ahmed Esawy Anatomical canal : - extends from perineal skin to dentate line Surgical canal : - extends from perineal skin to anorectal ring ( 1-1.5cm abov e dentate line ) - total length 4-5 cm
  7. 7. Dr Ahmed Esawy ANATOMY OF THE ANAL CANAL • The surgical anal canal extends from the anal verge distally to the anorectal ring proximally. • The anatomical anal canal extends from the anal verge distally to the dentate line proximally. • The dentate line is the junction of the ectoderm and endoderm in the anal canal. • The muscles of the anal canal can be regarded as forming a tube within a funnel : -The sides of the funnel are the levator ani muscles. - The stem of the funnel is the external anal sphincter. - The tube inside the stem of the funnel is the internal sphincter.
  8. 8. Dr Ahmed Esawy The total length of the surgical anal canal is about 4-5 cm. The anal sphincter is comprised of three layers: 1-Internal sphincter: continuance of the circular smooth muscle of the rectum, involuntary and contracted during rest, relaxes at defecation. 2-Intersphincteric space. 3-External sphincter: voluntary striated muscle, divided in three layers that function as one unit. These three layers are continuous cranially with the puborectal muscle and levator ani
  9. 9. Dr Ahmed Esawy Schematic representation of the anal canal with the probe in situ. Level 1, puborectalis. Level 2,deep (proximal) external anal sphincter (EAS). Level 3, superficial (mid) EAS. Level 4, subcutaneous (distal) EAS.
  10. 10. Dr Ahmed Esawy
  11. 11. Dr Ahmed Esawy
  12. 12. Dr Ahmed Esawy THE INTERNAL ANAL SPHINCTER • Is a thickened continuation of the circular muscle coat of the rectum. • The internal anal sphincter is 2.5 cm long and 2.5 mm thick.
  13. 13. Dr Ahmed Esawy THE EXTERNAL ANAL SPHINCTER • It was Formerly subdivided into a deep, superficial and subcutaneous portions but now is considered to be one muscle. • The external sphincter muscle is composed of voluntary muscles.
  14. 14. Dr Ahmed Esawy THE LEVATOR ANI MUSCLE • The anatomy of the levator ani muscle is important as it constitutes part of the sphincter mechanism of the anal canal. • The levator ani is a broad, thin muscle, attached to the side of the pelvis and united medially with its fellow to form the greater part of the floor of the pelvic cavity. • It consists of the following parts: The Ilio coccygeus. The pubococcygeus. The puborectalis.
  15. 15. Dr Ahmed Esawy
  16. 16. Dr Ahmed Esawy SURGICAL ANATOMY Line diagram shows coronal-view of the anal canal and perianal region.
  17. 17. Dr Ahmed Esawy Diagrams of anal sphincters. Coronal (A) and axial (B) views show the IAS and EAS and the other anal canal anatomic structures. A indicates anal canal; and R, rectum.
  18. 18. Dr Ahmed Esawy • Diagram shows the normal anatomy of the Anorecal region in the coronal plane a = anal canal, IRF = ischiorectal fossa, R = rectum (Quoted from John et al., 1999).
  19. 19. Dr Ahmed Esawy The total length of the surgical anal canal is about 4-5 cm. The anal sphincter is comprised of three layers: 1-Internal sphincter: continuance of the circular smooth muscle of the rectum, involuntary and contracted during rest, relaxes at defecation. 2-Intersphincteric space. 3-External sphincter: voluntary striated muscle, divided in three layers that function as one unit. These three layers are continuous cranially with the puborectal muscle and levator ani
  20. 20. Dr Ahmed Esawy The puborectal muscle is contracted at rest and accounts for the 80? angulation of the anorectal junction. It relaxes during defecation.
  21. 21. Dr Ahmed Esawy ENDOANAL ULTRASOUND (EUS) • It is a simple technique that analyzes anatomy in real time. • Peroxide-enhanced EUS was found to be a useful technique for detection of the presence, number, types and internal course of perianal fistulas.
  22. 22. Dr Ahmed Esawy ANATOMY AT US Four anatomical layers could be demonstrated on EUS: • The Plastic Cone: produces an inner, well defined ring of high reflectivity. • The Submucosa : is moderately reflective. • The Internal sphincter: a well-defined, circular, hypoechoic band. • The External sphincter: seen as a circular ring with low or intermediate echogenicity. • The Intersphincteric space: round hyperechoic ring between the hypoechoic internal & external sphincter.
  23. 23. Dr Ahmed Esawy • The Puborectalis muscle is identified as a hypoechoic U- shaped band at the level of the anorectal flexure. • The appearance of the anal canal at ultrasound is dependent on the height of the axial level being imaged. • The lower end of the canal is identified by the loss of the circumferential hypoechoic ring of the internal sphincter. • The upper end of the canal is identified by the hypoechoic horseshoe sling of the levator ani muscle posteriorly.
  24. 24. Dr Ahmed Esawy The normal 2-D anal sphincter complex
  25. 25. Dr Ahmed Esawy • At the anal verge, the internal anal sphincter is typically seen as an incomplete ring (arrows) that partially encircles the canal.
  26. 26. Dr Ahmed Esawy • The internal sphincter is seen as a continuous hypoechoic ring (large arrows) that surrounds the submucosal space (small arrows).
  27. 27. Dr Ahmed Esawy • At the cranial end, the external sphincter muscle becomes hypoechoic (arrow) and gives rise to the levator ani sling above this level (arrows ).
  28. 28. Dr Ahmed Esawy Normal appearance of the anal canal at US. Axial images of the anal canal show the normal anatomy from the most caudal aspect of the anal verge (a) extending up to the level of the levator ani muscle (d). (a) At the anal verge, the internal anal sphincter is typically seen as an incomplete ring (arrows) that partially encircles the canal.
  29. 29. Dr Ahmed Esawy Once the transducer is in the anal canal, the internal sphincter is seen as a continuous hypoechoic ring (large arrows) that surrounds the submucosal space (small arrows). The external anal sphincter appears as a less well-defined hyperechoic band immediately outside the internal sphincter .
  30. 30. Dr Ahmed Esawy At the cranial end of the anal canal, the external sphincter muscle becomes more hypoechoic (arrow in c).
  31. 31. Dr Ahmed Esawy The echogenicity of the internal anal sphincter increases with age, with the replacement of smooth muscle by the connective tissues. (Nielsen et al., 2001). The thickness of the internal anal sphincter is measured at the 3 O‟clock or 9 O‟clock position where the muscle is symmetrical. The muscle thickness is age dependant, increasing in thickness whilst become less distinct with age. (Rottenberg & Williams, 2003 ). In the adult; The measured thicknesses of the Internal anal sphincter range from (0.5–3.7 mm), while for External anal sphincter range from ( 5.8–9.8 mm).These measurement is less in neonate: the internal anal sphincter range from (0.8-1.9 mm), while external anal sphincter range from (1.2-2.3 mm). ( Nielsen et al., 2001).
  32. 32. Dr Ahmed Esawy Transverse endoanal US image shows (a) normal sphincter complex. ES = external sphincter, IS = internal sphincter
  33. 33. Dr Ahmed Esawy Transverse endorectal US image shows M: mucosa SM: sub mucosa MP: muscularis propria SS: sub serosa
  34. 34. Dr Ahmed Esawy Transverse endoanal US scan of the anal sphincter complex shows the internal sphincter muscle as a homogeneous hypoechoic circular band (curved arrows). 2-4 mm The external sphincter (straight arrows) is shown with mixed echogenicity. Note that the borders of the external sphincter are more difficult to define at endoanal US. Between the internal and external sphincters, the intersphincteric space (arrowheads) is depicted as a hyperechoic band. Within this band, the hypoechoic longitudinal muscle can be identified
  35. 35. Dr Ahmed Esawy Normal endoanal sonographic appearances of anal sphincters at 3 different levels. A, Upper anal canal level, identified by the horseshoe sling of the puborectalis muscle posteriorly (arrows) and loss of the EAS in the midline anteriorly. The IAS is also shown by arrowheads. B, Middle canal level, identified by the completion of the EAS ring anteriorly (black arrows) and maximum IAS thickness (white arrows). C, Lower canal level, defined as that immediately caudal to the termination of the IAS and comprising the subcutaneous the EAS (arrows). The anococcygeal ligament is also shown posteriorly (arrowheads). C
  36. 36. Dr Ahmed Esawy Normal appearance of the anal canal at US: Axial images of the anal canal show the normal anatomy of anal canal from the most caudal aspect of the anal verge at (a) extending up to the level of the levator ani muscle at (d): (a) At the anal verge, the internal anal sphincter is typically seen as an incomplete ring (arrows) that partially encircles the canal. (b) Once the transducer is in the anal canal, the internal sphincter is seen as a continuous hypoechoic ring (large arrows) that surrounds the submucosal space (small arrows). The external anal sphincter appears as a less well-defined hyperechoic band immediately outside the internal sphincter
  37. 37. Dr Ahmed Esawy (c, d) At the cranial end of the anal canal, the external sphincter muscle becomes more hypoechoic (arrow in c) and gives rise to the levator ani sling above this level (arrows in d)
  38. 38. Dr Ahmed Esawy Sphincter Muscle Thickness Measured at Endoanal Sonography, Endoanal MRI, and Phased Array MRI
  39. 39. Dr Ahmed Esawy Endovaginal sonography performed at the level of the bladder neck: the intramural portion of the urethra (yellow arrow), the anal canal (red arrow) and the pubovisceral muscle (short black arrow) are depicted.
  40. 40. Dr Ahmed Esawy transanal scans obtained with biplane 9-MHz transducer A, Axial image of healthy 20-year-old woman shows anterior portion of anal canal. Internal anal sphincter (IS) is prominent hypoechoic layer. B, Long-axis view corresponding to A shows internal sphincter (IS) in its entirety. Arrow marks anorectal junction, where thin muscularis propria thickens and becomes more round-appearing internal anal sphincter. There is no sphincter defect. Magnification on two crystal arrays is never exactly same.
  41. 41. Dr Ahmed Esawy curved transducer A, Axial image of healthy 40-year-old woman shows prominent hypoechoic ring of internal anal sphincter (IS). B, Rotating transducer by 90° from position in A shows anal sphincter in longitudinal view. Anal verge is on right and anorectal junction (arrow) on left of image.Internal anal sphincter (IS) appears as two longitudinal substantial hypoechoic bands.
  42. 42. Dr Ahmed Esawy anorectal junction with traditional end-fired transvaginal probe A, Axial image of lower rectum of healthy 56-year-old woman shows prominence of submucosa as broad echogenic layer. Muscularis propria (arrows) surrounds gut and is thin and hypoechoic. B, At anorectal junction of same patient as in A, thin muscularis propria thickens and becomes more roundappearing internal anal sphincter (IS). External anal sphincter (arrowheads) appears at this level as echogenic, rather poorly marginated sling-like structure around posterior aspect of anal canal. There is no sphincter defect.
  43. 43. Dr Ahmed Esawy
  44. 44. Dr Ahmed Esawy FUNCTION OF ANAL SPHINCTER AND PUBORECTALIS • Puborectalis: control continence over solid stool • Internal sphincter: control of liquid faeces • External sphincter provide internal sphincter in times of sudden need, such as raised intra abdominal presures • Anal cushion : the amount of blood flowing through its arteriovenous channels provide control over flatus
  45. 45. Dr Ahmed Esawy (a) Endoanal scan demonstrating the „„U‟‟-shaped puborectalis muscle, which attaches to the pubic rami anteriorly. (b) Endoanal scan demonstrating the internal anal sphincter (white arrow) and the external anal sphincter (black arrow). (c) Three dimensional endoanal ultrasound demonstrating the circumference/width as well as length of the anal sphincter defect.
  46. 46. Dr Ahmed Esawy Endoanal ultrasound of middle anal canal demonstrating IAS ,EAS in healthy asymptomatic female
  47. 47. Dr Ahmed Esawy
  48. 48. Dr Ahmed Esawy
  49. 49. Dr Ahmed Esawy Normal perianal anatomy of 47-year-old female volunteer imaged with CT CT (A-C) of inner internal sphincter (+), outer external sphincter (white dovetail arrows), levator ani muscle (B, thick arrows), and fat-containing ischioanal fossa (*).
  50. 50. Dr Ahmed Esawy Normal perianal anatomy of 45-year-old male volunteer imaged with CT anal sphincter complex is seen as two concentric rings. Inner internal sphincter (+), outer external sphincter (white or black dovetail arrows), levator ani muscle (thick arrows), fat containing ischioanal fossa (*).
  51. 51. Dr Ahmed Esawy MRI ANAL & PERIANAL REGION
  52. 52. Dr Ahmed Esawy Line diagram shows the normal anatomy of the perianal region in the axial plane The puborectal muscle has its origin on both sides of the pubic symphysis, forming a 'sling' around the anorectum.
  53. 53. Dr Ahmed Esawy • On axial and coronal MR images , the different layers of anal sphincter and the surrounding structures can be displayed perfectly
  54. 54. Dr Ahmed Esawy Drawing illustrates the anal clock, which is the surgeon's view of the perianal region when the patient is in the lithotomy position. The anterior perineum (p) is at the 12 o'clock position, and the natal cleft (n) is at the 6 o'clock position; 3 o'clock refers to the left lateral aspect, and 9 o'clock, the right lateral aspect of the anal canal. This schema exactly corresponds to the orientation of axial MR images of the perianal region.
  55. 55. Dr Ahmed Esawy Normal perianal anatomy. axialT1-weighted (a) and coronalT2-weighted (b) MR images show the normal anatomy of the perianal region. a = anal canal, es = external sphincter, iaf = ischioanal fossa, irf = ischiorectal fossa, R = rectum, straight arrow in a = the levator plate.
  56. 56. Dr Ahmed Esawy AxialCoronal
  57. 57. Dr Ahmed Esawy Normal perianal anatomy of 47-year- old female volunteer imaged with MR imaging. Anal sphincter complex is seen as two concentric rings. MR imaging: inner (+) internal sphincter and outer external sphincter (white dovetail arrows) appear relatively hypointense on all T2-weighted images without fat suppression (A-C). Levator ani muscle (B, thick arrows) forms superior boundary of fat- containing ischioanal fossa (*) on either side of anal canal.
  58. 58. Dr Ahmed Esawy Normal perianal anatomy of 45-year-old male volunteer imaged with MR imaging. MR imaging (T2-weighted without fat suppression images; A-C) anal sphincter complex is seen as two concentric rings. Inner internal sphincter (+), outer external sphincter (white or black dovetail arrows), levator ani muscle (thick arrows), fat containing ischioanal fossa (*).
  59. 59. Dr Ahmed Esawy Transperineal Ultrasound
  60. 60. Dr Ahmed Esawy The female pelvic floor from below.
  61. 61. Dr Ahmed Esawy 2D Transperineal Functional Imaging • Enterocele, Rectocele, Cystocele,Mesh, Slings. The patient position and the probe position during transperineal scanning
  62. 62. Dr Ahmed Esawy Describes the sample steps for performing transperineal 2D imaging using any abdominal probe transperineal imaging Identify the suitable transducer Identify the probe orientation Press the button on the side of the probe to activate the probe Set the depth at 6.7 cm Set the resolution at 1/32 Hz Place the transducer on the perineal area and obtain sagittal view of the bladder, vagina, and the rectum (including the midsagittal view of pubic symphysis) Adjust the gain Ask the subject to cough or bear down to visualize the movement of anterior, apical, and posterior compartments Ask the subject to “squeeze vaginal muscles or perform Kegels” to visualize the movement of the levator plate Transperineal US
  63. 63. Dr Ahmed Esawy This view demonstrates Incorrect positioning as the starting 2D field of view should include pubic symphysis anteriorly and the anorectal angle posteriorly. The field of view as demonstrated does not contain the pubic symphysis, and as such the distance from the edge of the pubic symphysis to the edge of the levator plate that creates the anorectal angle cannot be obtained. Depending on the patient‟s body habitus and pelvic floor laxity, the field of view may need to be made larger
  64. 64. Dr Ahmed Esawy This view demonstrates CORRECT positioning as the starting 2D field of view includes the pubic symphysis (S) anteriorly and the levator plate (LP) posteriorly. Also noted are the bladder (B), uterus (U), vagina (V), and anorectum (R) 2D Transperineal
  65. 65. Dr Ahmed Esawy Perineal ultrasound Axial images of the levator hiatus at rest (a), during contraction (b) and during valsalva manoeuvre (c). A) anal opening; U) urethra; V) vagina
  66. 66. Dr Ahmed Esawy The appearance of the puborectalis muscle in a rendered volume in the axial plane, using translabial 3D ultrasound with speckle reduction imaging. The two arrows indicate the gap between urethra and puborectalis insertion that can conveniently be palpated to determine muscle integrity
  67. 67. Dr Ahmed Esawy (a) Transperineal scan demonstrating the puborectalis muscle. (b) Transperineal scan demonstrating the internal anal sphincter (white arrow) and the external anal sphincter (black arrow). Note that the external anal sphincter is circumferential at a more distal level to the puborectalis.
  68. 68. Dr Ahmed Esawy Transperineal US show intact EAS ,IAS, with muscular atrophy in 75 y old female with fecal incontinence
  69. 69. Dr Ahmed Esawy Transperineal US demonstrating anal fistula
  70. 70. Dr Ahmed Esawy
  71. 71. Dr Ahmed Esawy 2D/3D Endovaginal
  72. 72. Dr Ahmed Esawy The view of the left side of the anterior compartment: ( a ) histologic section, ( b ) drawing of the anterior compartment structures, and ( c ) the left sagittal view of the 3D EVUS cube with the structures marked. BL bladder, CU compressor urethra, LCM longitudinal and circular layer, P pubic bone, PCF pubocervical fascia, SUG striated urogenital sphincter, TP trigonal plate, TR trigonal ring, U urethra, UT uterus, V vagina, VT vesical trigone 2D/3D Endovaginal Anterior Compartment Imaging
  73. 73. Dr Ahmed Esawy The view of the left side of the posterior compartment: ( a ) histologic section, ( b ) drawing of the posterior compartment structures, and ( c ) the left sagittal view of the 3D EVUS volume with the structures marked. EAS - m external anal sphincter main section,EAS - n external anal sphincter notch, EAS - sq external anal sphincter subcutaneous section, IAS internal anal sphincter, IAS - L internal anal sphincter length, IAS – T internal anal sphincter thickness, R rectum, RS rectovaginal septum, STP superfi cial transverse perinei, V vagina. 2D/3D Endovaginal posterior Compartment Imaging
  74. 74. Dr Ahmed Esawy view of the perineal area upon anal entry. The external anal sphincter (EAS), internal anal sphincter (IAS), probe in the anorectum (T), anal mucosa (AM),rectovaginal fascia (RVF), vaginal epithelium (VE),urethra (U), and the vagina are marked (V)
  75. 75. Dr Ahmed Esawy 2D vaginal ultrasound visualising the anal mucosa, IAS (IS), EAS and the ano-rectal junction. The vaginal transducer is placed in the posterior vaginal fourchette. A coronal section from the mid canal level (left) and a sagittal section (right) where also rectum (R) visualise
  76. 76. Dr Ahmed Esawy 3D vaginal ultrasound acquisitions seen in a transverse section (right) and in a sagittal section (left). VT: vaginal transducer. TPS: transversus perinei superficialis. CTP: centrum tendineum perinei. M: Anal mucosa. IAS: internal anal sphincter. EAS: external anal sphincter. PBR: puborectalis.
  77. 77. Dr Ahmed Esawy (a) Endovaginal scan demonstrating the puborectalis muscle (white arrow). (b) Endovaginal scan demonstrating the internal anal sphincter (white arrow) and the external anal sphincter (black arrow).
  78. 78. Dr Ahmed Esawy The perineal body (1) is hypoechogenic. The perineal membrane (2) is anchored in the perineal body and stretches towards the central point (4), and is relatively hypoechogenic. The hyperechogenic puboperineal muscles (3) are positioned anterior to the external anal sphincter (5). The hypoechogenic central point (4) is located dorsal to the vaginal introitus, gathering fibers from the perineal membrane, the superficial vaginal muscles, Colles‟ fascia and the external anal sphincter. Between the external (5) and the internal (7) anal sphincters is the thin hyperechogenic conjoined longitudinal muscle (6), which is interrupted by the perineal body immediately cranial to the external sphincter. The rectovaginal septum (8) is seen cranial to the perineal membrane. Inside the anal canal, the rectal columns (9) fill the lumen of the anal canal. Transvaginal sagittal midline ultrasound image of the anal canal and the perineum during pregnancy.
  79. 79. Dr Ahmed Esawy Transvaginal sagittal midline ultrasound image of the perineum, rectovaginal septum and anal canal immediately after delivery in a woman with a first-degree perineal tear with all perineal structures preserved. Marked edema is seen in the perineal membrane (2), rectovaginal septum (8) and perineal body (1). The fibers in the external anal sphincter (5) are intact, but it has a different appearance from that seen before delivery. 3,puboperineal muscle; 4, central point; 6, conjoined longitudinal muscle; 7, internal anal sphincter; 9, rectal columns.
  80. 80. Dr Ahmed Esawy Transvaginal semicircular transverse ultrasound image of the perineal body and anal canal during pregnancy. The perineal membrane (2) and the puboperineal muscle (3) meet in the midline in the perineal body (1). 5, external anal sphincter; 7, internal anal sphincter
  81. 81. Dr Ahmed Esawy Transvaginal sagittal midline ultrasound image of the anal canal immediately after delivery in a woman with a fourth-degree perineal tear. All structures in the perineum including the rectovaginal septum are torn, and are missing from the image. The following structures can be identified dorsal to the anal canal: external anal sphincter (5), conjoined longitudinal muscle (6),internal anal sphincter (7) and puborectal muscle (PR). Anterior to the anal canal, the cranial part of the internal anal sphincter (7) remains intact. 9, rectal columns.
  82. 82. Dr Ahmed Esawy 4D/3D SONOGRAPHIC DESCRIPTION OF THE SQUEEZE MECHANISM IN THE ANAL SPHINCTER
  83. 83. Dr Ahmed Esawy The anal squeeze mechanism in the external anal sphincter (EAS) has been described as two (alternative three) slings with different insertions that when contracting, pull different segments of the anal canal in anterior or posterior directions thus closing the anal canal . The function in the internal anal sphincter (IAS) is to maintain the resting pressure in the anal canal and to relax, thus enabling rectal sensations and evacuation. The third component of the anal sphincter - the conjoined longitudinal muscle (LM) - has not been discussed in relation to continence. The aim of the present study was to describe the movements in the anal sphincter during voluntary squeeze in healthy nulliparous women using a new ultrasonographic technique.
  84. 84. Dr Ahmed Esawy A ) At rest, the midsagittal external anal sphincter (EAS) (1) almost parallels the perineum (5). The longitudinal muscle (LM) (2) is hypoechogeneic and the internal anal sphincter (IAS) (3) is hyperechogeneic on transanal sonography. B). During a contraction, the EAS (1) is elongated in a cranial direction. The IAS (3) and the LM (2) are stretched and the walls of the IAS get thinner.
  85. 85. Dr Ahmed Esawy C) At rest in a transverse projection the EAS (1) and the IAS (3) are hyperechogeneic and the LM is hypoechogeneic. D). During a squeeze the walls of the IAS (3) are compressed, while the thickness of the LM (2) increases or remains unchanged. The EAS (1) compress the anal canal. Vagina (5).
  86. 86. Dr Ahmed Esawy During a squeeze of the anal sphincter complex, the EAS contracts by a diameter reduction and by an elongation in cranial direction. The LM moves in cranial direction along the anal canal and the walls of IAS are compressed. Thus, the present study did not confirm the old sling theory on anal continence
  87. 87. Dr Ahmed Esawy translabial ultrasound of the anal sphincter using the VCI-static technique in a patient with a IAS and EAS defect
  88. 88. Dr Ahmed Esawy
  89. 89. Dr Ahmed Esawy Anatomic relationships in the perianal region
  90. 90. Dr Ahmed Esawy Parts of levator ani muscles as seen from the pelvic aspect
  91. 91. Dr Ahmed Esawy

×