Pelvic Diaphragm

About pelvic diaphragm anatomy and pudendal canal.

1. Dr. Komal Parmar 22.12.16 Total number of Slides : 37 1 Pelvic Diaphragm and Pudendal Canal

2. Abdominopelvic Cavity 2

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5. Pelvis The term pelvis (‘basin’) is applied variously to the skeletal ring formed by the hip bones and the sacrum, the cavity therein, and even the entire region where the trunk and lower limbs meet . The term Pelvic Cavity refers to a  body cavity that is bounded by the bones of the pelvis. 5

6. False Pelvis Bounded on either side by the ilium; in front it is incomplete, presenting a wide interval between the anterior borders of the ilia; behind is a deep notch on either side between the ilium and the base of the sacrum . The false pelvis supports the intestines (specifically, the ileum and sigmoid colon), and transmits part of their weight to the anterior wall of the abdomen. Aka Greater Pelvis True Pelvis Bounded in front and below by the pubic symphysis and the superior rami of the pubis; above and behind, by the sacrum and coccyx; and laterally, by a broad, smooth, quadrangular area of bone, corresponding to the inner surfaces of the body and superior ramus of the ischium, and the part of the ilium below the arcuate line . The true pelvis contains the pelvic colon, rectum, bladder, and some of the reproductive organs. The rectum is at the back, in the curve of the sacrum and coccyx; the bladder is in front, behind the pubic symphysis .  In the female, the  uterus and vagina occupy the interval between these viscera. The pelvic splanchnic nerves arising at S2–S4 are in the lesser pelvis. Aka Lesser Pelvis 6

7. True Pelvis and Pelvic Floor 7 The true pelvis is a bowl-shaped structure formed from the sacrum, pubis , ilium, ischium, the ligaments which interconnect these bones and the muscles which line their inner surfaces . Begins at the level of Pelvic Inlet The floor or ‘outlet’ of the true pelvis is formed by the muscles of L evator A ni . Below the Levator Ani , lies the region known as Perineum . The deep limit of the perineum is the inferior surface of the pelvic diaphragm and its superficial limit is them skin which is continuous with that over the medial aspect of the thighs and the lower abdominal wall .

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9. Pelvic Viscera in Males 9

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11. Muscles and Fasciae of Pelvis 11 Fascia : Superiorly continuous with Visceral Pelvic Fascia Inferiorly continuous with Perineal Fascia Laterally Obturator Fascia

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13. Muscles of pelvis 13

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15. 15 Its fascia gives attachment to some of the fibres of levator ani and thus only the upper portion of the muscle lies lateral to the contents of the true pelvis, whilst the lower portion forms part of the boundaries of the ischio -anal fossa.

16. Levator Ani B road muscular sheet of variable thickness which is attached to the internal surface of the true pelvis and forms a large portion of the pelvic floor. The muscle is subdivided into named portions according to their attachments and the pelvic viscera to which they are related. These parts are often referred to as separate muscles , but the boundaries between each part cannot be easily distinguished and they perform many similar physiological functions. 16

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18. Levator Ani is subdivided into named portions according to their attachment to the pelvic viscera that they are related to Pubococcygeus ( Puboperinealis , Puboprostaticus / pubovaginalis , Puboanalis , Puborectalis ), Iliococcygeus , Puborectalis 18 Ischiococcygeus (aka Coccygeus ) is referred to as a separate muscle lying posterosupiriorly to Levator Ani .

19. Perineal Body The perineal body is an irregular and   fibromuscular mass. It is located at the junction of the urogenital and anal triangles – the  central point  of the perineum . Anatomically, the perineal body lies just deep to the skin. It functions as a point of  attachment  for muscle fibres from the pelvic floor and the perineum itself Anococcygeal Raphae The  anococcygeal body  ( anococcygeal ligament , or  anococcygeal raphe ) is a fibrous median raphe in the floor of the pelvis, which extends between the coccyx and the margin of the anus. It is composed of fibers of the  levator ani muscle  which unite with the muscle of the opposite side, muscle fibres from  external anal sphincter  and  fibrous connective tissue . 19

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22. Components of Levator Ani : Pubococcygeus 22

23. Components of Levator Ani : Iliococcygeus The iliococcygeal part is attached to the inner surface of the ischial spine below and anterior to the attachment of ischiococcygeus and to the tendinous arch as far forward as the obturator canal. The most posterior fibres are attached to the tip of the sacrum and coccyx but most join with fibres from the opposite side to form Anal raphe. 23

24. Puborectalis Ischiococcygeus It lies as the most posterosuperior portion of levator ani and arises as a triangular musculotendinous sheet with its apex attached to the pelvic surface and tip of the ischial spine. The base of the muscle is attached to the lateral margins of the coccyx and the fifth sacral segment. 24

25. Relations The superior, pelvic surface of levator ani is separated only by fascia (superior pelvic diaphragmatic, visceral and extraperitoneal ) from the urinary bladder, prostate or uterus and vagina, rectum and peritoneum . Its inferior , perineal , surface forms the medial wall of the ischio -anal fossa and the superior wall of the anterior recess of the fossa, both being covered by inferior pelvic diaphragmatic fascia. The posterior border is separated from the coccyx by areolar tissue. The medial borders of the two levator muscles are separated by the visceral outlet, through which pass the urethra, vagina, and anorectum . 25

26. Vascular Supply Inferior Gluteal A Inferior Vesical A Inferior Pudendal A Innervation Nerves to Levator Ani (S3-S4) 26

27. Pelvic Fasciae Parietal Pelvic Fascia : Obturator F F over Piriformis F over Levator Ani . Pelvic Diaphragm= Fascia + Levator Ani Presacral F Visceral Pelvic Fascia Derived from mesenteries Cardinal and Uterosacral Ligaments White Line of Pelvic Fascia 27

28. Vasculature of Pelvis 28

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30. Nerves 30

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32. Pudendal Canal 32 4 cm above the lower limit of Ischial Tuberosity

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