David Fu

1. The Perineum and theperitoneumSchool of Basic Medical Science of Jiujiang University David Fu

2. Chapter 7The Perineum

3. The Perineum General features • Region of below pelvic diaphragm • A diamond-shape space whose boundaries are those of the pelvic outlet • Lower border of symphysis pubis • Rami of pubis and ischium • Ischial tuberosities • Sacrotuberous ligament • The coccyx • In the narrow sense of perineum, the female perineum is the soft tissue structure between anus and the posterior end of the perineal cleft.

4. Two triangles An imaginary line drawn between the two ischial tuberosities divides perineum into anterior and posterior triangles • Urogenital region(anterior)－differs in male and female • Anal region (posterior)－similar in both sexes

5. Urogenital triangle This region is between the pubic arches of the both sides. Its apex is directed forward and the base is backward. Fasciae of Urogenital triangle Superficial fascia has two layers • The superficial or fatty layer • The deep or membranous layer (superficial fascia of perineum or Colles fascia) Anteriorly－ it is continuous with: • Dartos of the scrotum • Fascia of the penis • Membranous layer of superficial fascia of the abdominal wall known as the fascia of Scarpa Deep fascia has two layers • Superior fascia of urogenital diaphragm • Inferior fascia of urogenital diaphragm

6. Scarpa’s fascia Camper’s fascia Line of fusion Position of penis Fascia later Position of scrotum

7. Urogenital diaphragm • Triangular in shape • Attached laterally to ischiopubic rami and ischial tuberosities • Formed by sphincter of urethra, deep transverse perineal muscle, superior and inferior fascia of urogenital diaphragm • In male, the urethra pass through it • In female, the urethra and vagina pass through it

8. Fascia of Scarpa Fascia of the penis Dartos of the scrotum Superior fascia of urogenital diaphragm Deep perineal space Inferior fascia of urogenital diaphragm Superficial perineal space superficial fascia of perineum

9. Anal Triangle In this triangle there are the levator ani, coccyges, and external anal sphincters, also includes the superior and inferior fasciae of pelvic diaphragm. The anus is in the center of the triangle, which passes through this region. There are two large spaces on both sides of the anal canal, which are called the ischiorectal fossa.

10. Anal sphincters • Internal • Smooth muscle (thickened circular muscle coat) • Surrounds upper two-thirds of anal canal • Autonomic nerve supply • External • Striated muscle • Surrounds lower two-thirds of anal canal • Three parts－subcutaneous, superficial and deep • Innervation by anal nerves of pudendal nerve and branches of S4

11. Ischioanal fossa Paired, wedge-shaped, fat-filled spaces on either side of anal canal Boundaries • Apex－conjunctive area of inferior fascia of pelvic diaphragm and fascia covering the obturator internus • Base－skin of anal region • Medial－sphincter ani externus, levator ani, coccygeusand inferior fascia of pelvic diaphragm • Lateral－ischial tuberosity, obturator internus and fascia

12. Anterior • Posterior border of urogenital diaphragm • Forward projection of anterior recess of fossabetween pelvic diaphragm above and urogenital diaphragm below • Posterior • backward projection of posterior recess of fossabetween gluteus maximus, sacrotuberous ligament and coccyx

13. Contents • Fat • Internal pudendal artery and vein and their rectal branches • Pudendal nerve and its inferior rectal branch Vessels and nerves enter from gluteal region, through lesser sciatic foramen, travel on a fascial canal－the pudental canal (Alcock’s) －on the lateral wall of fossa, and extend forward into urogenital region

14. Chapter 8 ThePeritoneum

15. General features • The peritoneum is a thin serous membrane that line the walls of the abdominal and pelvic cavities and cover the organs within these cavities • Parietal peritoneum－lines the walls of the abdominal and pelvic cavities • Visceral peritoneum－covers the organs • Peritoneal cavity－the potential space between the parietal and visceral layer of peritoneum, in the mail, is a closed sac, but in the female, there is a communication with the exterior through the uterine tubes, the uterus, and the vagina

16. Function • Secretes a lubricating serous fluid that continuously moistens the associated organs • Absorb • Support viscera fowler position supine position

17. Intraperitoneal viscera Interperitoneal viscera Retroperitoneal viscera The relationship between viscera and peritoneum • Intraperitoneal viscera－viscera completely surrounded by peritoneum, example, stomach, superior part of duodenum, jejunum, ileum, cecum, vermiform appendix, transverse and sigmoid colons, spleen and ovary • Interperitoneal viscera－most part of viscera surrounded by peritoneum, example, liver, gallbladder, ascending and descending colon, upper part of rectum, urinary bladder and uterus • Retroperitoneal viscera－some organs lie on the posterior abdominal wall and are covered by peritoneum on their anterior surfaces only, example, kidney, suprarenal gland, pancreas, descending and horizontal parts of duodenum, middle and lower parts of rectum, and ureter

18. Interperitoneal viscera

19. Structures which are formed by peritoneum Omentum－two-layered fold of peritoneum that extends from stomach to adjacent organs

20. Lessor omentum－two-layered fold of peritoneum which extends from porta hepatis to lesser curvature of stomach and superior part of duodenum • Hepatogastric ligament －extends from porta hepatis to lesser curvature of stomach • Hepatoduodenal ligament • Extends from porta hepatis to superior part of duodenum • Contains common bile duct, proper hepatic a. and hepatic portal v.

21. Omental foramen • Behind the right border of hepatoduodenal ligament • Superior－caudate lobe of liver • Inferior－superior part of duodenum • Anterior－hepatodudenal ligament • Posterior－peritoneum covering the inferior vena cava

22. Greater omentum －four-layered fold of peritoneum, the anterior two layers descend from the greater curvature of stomach and superior part of duodenum and hangs down like an apron in front of coils of small intestine, and then turns upward and attaches to the transverse colon. If an infection occurs in the intestine, plasma cells formed in the lymph nodes combat the infection and help prevent it from spreading to the peritoneum.

23. Lessor omentum Greater omentum

24. Omental bursa Position－situated behind the lesser omentum and stomach Walls • Superior－peritoneum which covers the caudate lobe of liver and diaphragm • Anterior－formed by lesser omentum, peritoneum of posterior wall of stomach, and anterior two layers of greater omentum • Inferior－conjunctive area of anterior and posterior two layers of greater omentum • Posterior－formed by posterior two layers of greater omentum, transverse colon and transverse mesocolon, peritoneum covering pancreas, left kidney and suprarenal gland

25. Left－formed by the spleen, gastrosplenic ligament and splenorenal ligament • Right－formed by omental foramen The Omental bursa (lesser sac) communicates with the greater sac through the omental foramen.

26. Mesenteries or mesocolons－two-layered fold of peritoneum that attach part of the intestines to the posterior abdominal wall

27. Mesentery－suspends the small intestine from the posterior abdominal wall • Broad and a fan-shaped • Consists of two peritoneal layers • Intestinal border－folded, 7 m long • Radix of mesentery • 15 cm long • Directed obliquely from left side of L2 to in front of right sacroiliac joint

29. Mesoappendix • Triangular mesentery－extends from terminal part of ileum to appendix • Appendicular artery runs in free margin of the mesoappendix

30. Transverse mesocolon－a double fold of peritoneum which connects the transverse colon to the posterior abdominal wall Sigmoid mesocolon －inverted V-shaped, with apex located in front of left ureter and division of common iliac artery

31. Ligaments－two-layered folds of peritoneum that attached the lesser mobile solid visera to the abdominal wall Ligaments of liver • Falciform ligament of liver • Consists of double peritoneal layer • Extends from anterior abdominal wall (umbilicus) to live • Free border of ligament site of ligamentum teres

32. Coronary ligament －the area between upper and lower parts of the coronary ligament is the bare area of live, this area is devoid of peritoneum and lies in contract with the diaphragm • Left and right triangular ligaments －formed by right extremity of coronary ligament and left leaf of falciform ligament, respectively

33. Hepatogastric ligament • Hepatoduodenal ligament • Ligamentum teres hepatis

34. Ligaments of spleen • Gastrosplenic ligament －a double layer of peritoneum that connects the fundus of stomach to hilum of spleen. In this double layer of peritoneum are the short gastric and left gastroepiploic vessels • Splenorenal ligament －extends between the hilum of spleen and anterior aspect of left kidney. The splenic vessels lies within this ligament, as well as the tail of pancreas • Phrenicosplenic ligament • Splenocolic ligament

35. Ligaments of stomach • Hepatogastric ligament • Gastrosplenic ligament • Gastrophrenic ligament • Gastrocolic ligament • Gastropancrastic ligament

36. Folds and recesses of posterior abdominal wall • Superior duodenal fold and recess • Inferior duodenal fold and recess • Intersigmoid recess－formed by the inverted V attachment of sigmoid mesocolon

37. Retrocecal recess －in which the appendix frequently lies • Hepatorenal recess －lies between the right lobe of liver, right kidney, and right colic flexure, and is the lowest parts of the peritoneal cavity when the subject is supine

38. Folds and fossas of anterior abdominal wall • Medial umbilical fold－contain the remnant of urachus (median umbilical ligaments) • Medial umbilical fold－contains remnants of the umbilical arteries (medial umbilical ligaments) • Lateral umbilical fold－contains the inferior epigastric vessels • Supravesical fossa • Medial inguinal fossa • Lateral inguinal fossa

39. Pouches • In male－rectovesical pouch • In female • Rectouterine pouch－between rectum and uterus • Vesicouterine pouch －between bladder and uterus

40. Peritoneal subdivisions The transverse colon and transverse mesocolon divides the greater sac into supracolic and infracolic compartments. These compartments form channels or recesses that determine how or where peritoneal fluid gravites or spreads. Supracolic compartments (subphrenic space)－lies between diaphragm and transverse colon and transverse mesocolon. It is subdivided by the liver into suprahepatic space and subhepatic space. Infracolic compartments－lies below the transverse colon and transverse mesocolon. It is further divided by mesentery of small interstine into right and left parts. The latter drains into the pelvis. The paracolic grooves are longitudinal depressions lateral to the ascending and descending colon.