Anatomy of Rectum


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Anatomy of Rectum

  1. 1. Tirunelveli Medical College<br />Department of Anatomy<br />
  2. 2. The Anatomy Of<br />Rectum<br />Presentation by<br />K Hari Krishnan<br />I Year MBBS (2008-’09)<br />Tirunelveli Medical College<br />Tirunelveli, Tamilnadu, India<br />
  3. 3. Distal part of the large gut<br />The pelvic part of the alimentary tract<br />Introduction<br />
  4. 4. Rectum<br />
  5. 5. Location<br />Posterior part of the lesser pelvis<br />In front of lower three pieces of sacrum and the coccyx<br />
  6. 6. Extent<br />Begins at the rectosigmoid junction<br />at level of third sacral vertebra<br />Ends at the anorectal junction<br />2-3 cm in front of and a little below the coccyx<br />
  7. 7. Length<br />13 cm (5 in.)<br />Diameter<br />4 cm (in the upper part)<br />Dilated (in the lower part)<br />Dimensions<br />
  8. 8. Dimensions<br />
  9. 9. Downwards and backwards<br />Downwards<br />Downwards and forwards<br />Course<br />
  10. 10. Flexures<br />Antero-posterior flexures (2 in number)<br />Sacral flexure<br />Follows the curve of the sacrum and coccyx<br />
  11. 11. Flexures<br />Antero-posterior flexures<br />Perineal flexure / Anorectal flexure<br />80° anorectal angle<br />In the terminal part of the rectum<br />At the anorectal junction<br />Here the rectum perforates the pelvic diaphragm to become the anal canal<br />
  12. 12.
  13. 13. Flexures<br />Lateral flexures (3 in number) – correspond to the transverse rectal folds<br />Superior<br />Convex to the right<br />Intermediate<br />Convex to the left<br />Most prominent<br />Inferior<br />Convex to the right<br />
  14. 14. Superior 1/3rd of the rectum<br />Covered by peritoneum on the anterior and lateral surfaces<br />Middle 1/3rd of the rectum<br />Covered by peritoneum on the anterior surface<br />Inferior 1/3rd of the rectum<br />Subperitoneal – Devoid of peritoneum<br />Peritoneal Relations<br />
  15. 15. Relations<br />
  16. 16. In males<br />Upper 2/3rd<br />Rectovesical pouch<br />Coils of ileum<br />Sigmoid colon<br />Lower 1/3rd<br />Fundus (base) of the urinary bladder<br />Terminal parts of the ureters<br />Seminal vesicles<br />Ductus deferentes<br />Prostate<br />Visceral Relations<br />Anterior<br />
  17. 17. Relations<br />
  18. 18. Visceral Relations<br />Posterior<br />In females<br />Upper 2/3rd<br />Rectouterine pouch, which separates the rectum from the uterus and from the upper part of vagina<br />Coils of ileum<br />Sigmoid colon<br />Lower 1/3rd<br />Lower part of vagina<br />
  19. 19. Relations<br />
  20. 20. Posterior Relations<br />Bones<br />Lower three pieces of sacrum<br />Coccyx<br />Ligaments<br />Anococcygeal ligament<br />Muscles<br />Piriformis<br />Coccygeus<br />Levator ani<br />Vessels<br />Median sacral<br />Superior rectal<br />Lower lateral sacral<br />Nerves<br />Sympathetic chain with ganglion impar<br />Ventral primary rami of S3, S4, S5, Co1<br />Pelvic splanchnic nerves<br />Lymph nodes and lymphatics<br />Fat<br />
  21. 21. Relations<br />
  22. 22. Relations<br />
  23. 23.
  24. 24. Arterial Supply<br />Superior rectal artery<br />Direct continuation of Inferior mesenteric artery<br />Enters the pelvis by descending in the root of the sigmoid mesocolon and divides into right and left branches, which pierce the muscular coat and supply the mucous membrane<br />They anastomose with one another and with the middle and inferior rectal arteries<br />Middle rectal artery<br />Small branch of anterior division of Internal iliac artery<br />Run in the lateral ligaments of the rectum<br />Supplies the muscular coat of the lower part of rectum<br />Inferior rectal artery<br />Branch of Internal pudental artery in the perineum<br />Anastomoses with the middle rectal artery at the anorectal junction<br />Median sacral artery<br />Direct branch from the dorsal surface of Aorta near its inferior end<br />Descends in the median plane<br />Supplies the posterior wall of the anorectal junction<br />
  25. 25. Arterial Supply<br />
  26. 26. Arterial Supply<br />
  27. 27.
  28. 28. Venous Drainage<br />
  29. 29. Venous Drainage<br />Submucosal rectal venous plexus<br />Surrounds rectum<br />Communicates<br />vesical venous plexus – males<br />uterovaginal venous plexus – females<br />2 Parts:<br />Internal rectal venous plexus<br />Deep to the epithelium of rectum<br />Drains into Superior rectal vein<br />External rectal venous plexus<br />External to the muscular wall of rectum<br />Superior portion: drains into Superior rectal vein<br />Middle portion: drains into Middle rectal vein<br />Inferior portion: drains into Inferior rectal vein<br />
  30. 30. Superior rectal vein<br />Formed from Internal rectal venous plexus<br />Consists of 6 main tributary veins<br />Continues upwards as Inferior mesenteric vein<br />Middle rectal vein<br />Formed from the middle portion of External rectal venous plexus<br />Pass alongside middle rectal artery<br />Drains into the anterior division of Internal iliac vein on the lateral wall of the pelvis<br />Inferior rectal vein<br />Formed from the inferior portion of the Inferior rectal vein<br />Drains into the Internal pudental vein<br />Venous Drainage<br />
  31. 31. Venous Drainage<br />
  32. 32. Superior half of the rectum<br />Pararectal lymph nodes, located directly on the muscle layer of the rectum<br />Inferior mesenteric lymph nodes, via either the sacral lymph nodes or the nodes along the superior rectal vessels<br />Inferior half of the rectum<br />Sacral group of lymph nodes or Internal iliac lymph nodes<br />Lymphatic Drainage<br />
  33. 33. Lymphatic Drainage<br />
  34. 34. Nerve Supply<br />Sympathetic nerve supply<br />L1, L2 fibres<br />Through Superior rectal and Inferior hypogastric plexuses<br />Vasoconstrictor<br />Inhibitory to musculature of rectum<br />Motor to internal sphincter<br />Carry sensations of pain<br />Parasympathetic nerve supply<br />S2, S3, S4 fibres<br />Passes via pelvic splanchnic nerves and inferior hypogastric plexuses to rectal (pelvic) plexus<br />Motor to musculature of the rectum<br />Inhibitory to internal sphincter<br />Carry sensations of pain and distension<br />
  35. 35. Nerve Supply<br />
  36. 36. Nerve Supply<br />
  37. 37.
  38. 38. Interior<br />
  39. 39. Interior<br />Longitudinal folds<br />Present in lower part of the empty rectum<br />Effaced during distension<br />
  40. 40. Interior<br />Transverse folds(Houston’s valves or plicae transversae recti)<br />Marked in rectal distension<br />Superior fold<br />At beginning of rectum<br />Projects from the right or the left wall<br />Middle fold<br />Above the rectal ampulla<br />Projects from the anterior and right walls<br />Largest and most constant<br />Inferior fold<br />About 2.5 cm below the middle fold<br />Projects from the left wall<br />Variable<br />Occasional fourth fold<br />About 2.5 cm above the middle fold<br />Projects from the left wall<br />
  41. 41. Interior<br />
  42. 42. Histology<br />
  43. 43.
  44. 44. Supports<br />Pelvic Floor<br />Levator ani muscles<br />Fascia of Waldeyer<br />Condensation of pelvic fascia behind rectum<br />Lower part of ampulla to Sacrum<br />Encloses Superior rectal vessels and lymphatics<br />Lateral ligaments of Rectum<br />Denonvilliers fascia<br />Pelvic peritoneum<br />Perineal body<br />
  45. 45. Supports<br />
  46. 46.
  47. 47. Supports<br />
  48. 48. Clinical<br />Aspects<br />
  49. 49. Digital Rectal Examination<br />Examination to check for abnormalities of organs or other structures in the pelvis and lower abdomen<br />To check for<br />growths in or enlargement of the prostate gland in males. A tumor in the prostate can often be felt as a hard lump<br />problems in female reproductive organs (uterus and ovaries)<br />rectal bleeding or tumors in the rectum<br />
  50. 50. Proctoscopy<br />Proctoscopy - Visual examination of the rectum and anus<br />Visualizing the interior of the rectum and anal canal<br />Helps in revealing ulcers, abnormal growths and diverticula<br />
  51. 51. Sigmoidoscopy<br />Sigmoidoscope<br />An endoscope for viewing the lumen of the sigmoid colon<br />
  52. 52. Sigmoidoscopes<br />
  53. 53. Rectal Prolapse<br />Rectocoele<br />Protrusion of the mucous membrane and submucosa of the rectum outside the anus for approximately 1–4 cm<br />Common in<br />Children: 1 – 3 years<br />Elderly people<br />Middle-aged women<br />
  54. 54. Partial Rectal Prolapse<br />Rectal mucous membrane and submucous coat protrude for a short distance outside the anus<br />Common in children<br />
  55. 55. Complete Rectal Prolapse<br />Procidentia<br />Whole thickness of the rectal wall protrudes through the anus<br />A sliding hernia through the pelvic diaphragm<br />Common in adults<br />Associated with rectal incontinence<br />
  56. 56. Causes<br />In infants<br />Undeveloped sacral curve<br />Reduced resting anal tone – diminished support to the mucosal lining of anal canal<br />In children<br />Diminution of fat in ischiorectal fossae<br />Diarrhoea<br />Severe whooping cough<br />Sudden loss of weight<br />Fibrocystic disease<br />Neurological causes<br />Mal-development of pelvis<br />Rectal Prolapse<br />
  57. 57. Causes<br />In adults<br />Haemorrhoids<br />Torn perineum<br />Straining from urethral obstruction<br />Following operation for fistula in ano<br />In the elderly<br />Atony of sphincter mechanism<br />Rectal Prolapse<br />
  58. 58. Treatment<br />Submucous injections<br />Excision of the prolapsed mucosa<br />Surgery<br />Rectal Prolapse<br />
  59. 59. Rectal Carcinoma<br />Found mainly in<br />Rectosigmoid junction<br />Ampulla<br />Bleeding per rectum<br />Initial finding – Lymphatics around the bowel<br />Later – lymph nodes along superior rectal and middle rectal arteries<br />Venous spread – Superior rectal vein to portal vein<br />Liver – secondary deposits<br />
  60. 60. Rectal Carcinoma<br />Treatment<br />Rectal excision and total mesorectal excision<br />Abdomino-perineal excision with a permanent colostomy<br />Adjuvant preoperative radiotherapy<br />Liver resection for liver metastases <br />
  61. 61. Gray’s Anatomy: The Anatomical Basis of Clinical Medicine<br />Gray’s Anatomy for Students<br />Richard S. Snell – Clinical Anatomy by Regions<br />Keith L. Moore – Essential Clinical Anatomy<br />Last’s Anatomy - Regional and Applied<br />Frank H. Netter – Atlas of Human Anatomy<br />Bailey and Love’s Short Practice of Surgery<br />Sources<br />
  62. 62. Thank You!<br />