Pelvis and perineum

Fundamentals of pelvis, perineum and male genitalia anatomy. contains short notes with atlas. easy for self study of preclinical and clinical students and residents. clinically important common correlations are included. well animated power point presentation.

1. Pelvis and Perineum By: Addisu Alemu, MD

2. to review the significant anatomy of the pelvic walls relative to clinical problems. age and sexual differences and to the anatomic features associated with pelvic examinations . Identify the structures of the male Perineum and reproductive systems Objectives 2

3. Pelvis Greater pelvis Lesser pelvis Perineum Introduction 3

4. Bear the weight of the upper body when sitting and standing transmits body weight from the vertebral column to the femurs it contains, supports, and protects the pelvic viscera and provides attachment for trunk and lower limb muscles Functions of pelvic girdle 4

5. The Bony Pelvis 5

6. Triradiate cartilage 6

7. Hip bones ischiopubic rami 7

8. Bone marrow aspiration 8

9. Pelvic inlet 9 terminal line

10. Mid Pelvis 10

11. Anteroposteror diameter of pelvic outlet (varies 9.5-11.5cm because of mobility of coccyx) Transverse diameter of pelvic outlet (~11cm) Pelvic Outlet 11

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13. increases in size of interpubic disc Increased levels of sex hormones and relaxin hormones Increased movement at the pelvic joints coccyx is also able to move posteriorly. Relaxation of the sacro -iliac joints and pubic symphysis permits 10–15% increase in diameters (mostly transverse, including the interspinous distance. True (obstetrical ) diameter remains unchanged Pelvic Changes during the pregnancy 13

14. COMPARISON OF MALE AND FEMALE BONY PELVES 14

15. Types of Pelvis 15

16. Weak areas of the pelvis, are the pubic rami, the acetabula , the region of the sacro -iliac joints the alae of the ilium. Pelvic Fractures 16

17. Minor fracture Pieces of pelvis break off with intact pelvic ring Major fracture Opens the pelvic ring often multiple fracture Classification Open book fracture. Straddle fracture Vertical shear fracture 17

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19. pelvis muscles form two groups. Piriformis and obturator internus , are part of the walls of the pelvis, primarily considered muscles of the lower limb MUSCLES AND FASCIAE OF THE PELVIS 19

20. 2. Levator ani and coccygeus form the pelvic diaphragm and delineate the lower limit of the true pelvis The fasciae investing the muscles are continuous with visceral pelvic fascia above, perineal fascia below and obturator fascia laterally. Ischiococcygeus ( coccygeus ) may be nearly completely tendinous 20

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22. according to attachments and fiber course Puborectalis – forms puborectal sling Pubococcygeus anococcygeal body - fibrous raphe formed by merged medial fibers pubovaginalis or puboprostaticus puboperinealis – extending medially and blending with the fascia around midline structures Iliococcygeus - arises from the posterior tendinous arch and ischial spine and blends with the anococcygeal body posteriorly Levator ani 22

23. 23 ischio -anal fossae

24. 24 Urogenital hiatus

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27. 27 Male

28. is connective tissue that occupies the space between the membranous peritoneum and the muscular pelvic walls and floor not occupied by the pelvic viscera. Continuation endoabdominal fascia Pelvic fascia 28

29. parietal pelvic fascia lines the inner walls and floor of the pelvis named for the muscle that is covered Continuous with transversalis and iliopsoas fascias . 29 MEMBRANOUS PELVIC FASCIA

30. visceral pelvic fascia – ensheathes the pelvic organs (forming the adventitial layer) become continuous with parietal layer where the organs penetrate the pelvic floor froming thickened condensations of connective tissue - tendinous arch of pelvic fascia - running from the pubis to the ??sacrum Parts of tendinous arch of pelvic fascia puboprostatic ligament in males; pubovesical ligament in females – anteriormost part sacrogenital ligaments - posteriormost part - Extends from sacrum to prostate or vagina 30

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32. Is a fascia between parietal and visceral pelvic fascia which froms a connective tissue matrix for pelvic viscera. Considered as extraperitoneal or subperitoneal endopelvic fascia which could be loose areolar (fatty) tissue – in retropubic , retrorectal spaces fascial condensations or pelvic “ ligaments” - Hypogastric sheath ENDOPELVIC FASCIA: 32

33. Hypogastric ( neurovascular) sheath Presacral (potential) space Retropubic ( prevesical ) space Superior vesical artery in lateral ligament of bladder lateral rectal ligament (middle rectal vessels) Cardinal ligament Tendinous arch of levator ani Tendinous arch of pelvic fascia Rectovaginal ( potential) space 33 uterine artery Lateral pubovesical ligament Medial pubovesical ligament Internal iliac vessels Vesicocervical fascial Fibers ( paracolpium )

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35. Pelvic Arteries main arteries entering the lesser pelvis internal iliac and ovarian arteries (females only) are paired median sacral and superior rectal arteries are unpaired multiple anastomoses occur, providing an extensive collateral circulation Blood vessels of the pelvis 35

36. is the principal artery of the pelvis supplying most of the blood to pelvic viscera and some to the musculoskeletal part Branches from the anterior trunk supply pelvic viscera, perineum, gluteal region, adductor region of the thigh, in the fetus, the placenta Branches from the posterior trunk supply lower posterior abdominal wall, posterior pelvic wall, gluteal region Internal iliac artery 36

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38. Iliolumbar and Lumbar median sacral and lateral sacral superior rectal and middle rectal inferior gluteal and deep artery of the thigh collateral circulation 38

39. Pelvic veins follow the course of all branches of the internal iliac artery except for the umbilical artery (absent) and the iliolumbar artery ( drain into the common iliac veins) Pelvic Veins 39

40. The various plexuses unite and are drained mainly by tributariesinternal iliac veins some drain through superior rectal vein into inferior mesenteric vein - portacaval shunt lateral sacral veins into internal vertebral venous plexus median sacral vein ovarian veins (in females) Pelvic venous plexuses 40

41. Lymphatic drainage follows a pattern that generally follows the pattern of venous drainage through variable minor and major sets of lymph nodes Exception = the superior parts of the middle to anterior pelvic organs → External iliac lymph nodes However, pelvic lymph nodes are highly interconnected that the pattern is not sufficiently predictable to allow the progress of metastatic cancer from pelvic organs to be anticipated or staged Lymphatic drainage of the pelvis 41

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43. Pelvic structures are innervated mainly by the sacral (S1 -S4) and coccygeal spinal nerves and the pelvic part of autonomic nervous system Sacral plexus Originates from the anterior rami of L4, L5, S1–S4 Branches from the plexus supply: pelvic muscles muscles of the hip skin of buttock and the back of thigh Nerves of pelvis 43

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46. 46 Pudendal nerve Leaves the pelvis through the greater sciatic foramen Then hooks around the ischial spine and sacrospinous ligament and enters the perineum through the lesser sciatic foramen Accompanied by the internal pudendal vessels Innervates skin and skeletal muscles of the perineum, including the external anal and external urethral sphincters Mediates the act of erection Voluntary control of urination

47. 47 PUDENDAL CANAL AND ITS NEUROVASCULAR BUNDLE

48. 1. Sacral sympathetic trunks are the inferior continuation of the lumbar sympathetic trunks descend on the pelvic surface of the sacrum just medial to the pelvic sacral foramina converge to form the small median ganglion impar (coccygeal ganglion ). send communicating branches (gray rami communicantes ) to each of the anterior rami of the sacral and coccygeal nerves also send branches to the median sacral artery and the inferior hypogastric plexus Function: provide postsynaptic fibers to the sacral plexus for sympathetic innervation of the lower limb Pelvic Autonomic Nerves 48

49. 49 Autonomic nerves of pelvis

50. superior hypogastric plexus – networks of sympathetic and visceral afferent nerve fibers conveyed through (L3 and L4) splanchnic nerves. In pelvis Divides into right and left hypogastric nerves and descend lateral to the rectum within hypogastric sheaths to merge with the pelvic splanchnic nerves to form the right and left inferior hypogastric plexuses . 50 2. Hypogastric plexuses

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52. The inferior hypogastric plexuses thus contain both sympathetic and parasympathetic fibers as well as visceral afferent. This fibers continue through the lamina of the hypogastric sheath as sub-plexuses ( pelvic –plexuses ) supplying the pelvic structures from lateral aspect 52 Hypogastric …

53. Periarterial plexuses Sympathetic fibers enter the pelvis surrounding superior rectal, ovarian, and internal iliac arteries Pelvic splanchnic nerves: Arise from anterior rami of spinal nerves S2, S3 , S4 of the sacral plexus (presynaptic fibers) pathway for parasympathetic innervation of pelvic viscera and descending and sigmoid colon. 53

54. All visceral afferent fibers conducting reflexive sensation travel with parasympathetic fibers. pelvic pain line - the pelvic pain line corresponds to the inferior limit of the peritoneum superior to the pain line follow sympathetic fibers retrograde portions of viscera inferior to the pain line follow the parasympathetic fibers retrograde to reach cell bodies in the spinal sensory ganglia of S2–S4 . Exception = the pain line occurs in the middle of the sigmoid colon . VISCERAL AFFERENT INNERVATION 54

55. Primary reproductive organs produce gametes Secondary reproductive organs: Seminal fluid Storage of spermatozoa Internal Genital organs External Genital organs Male Genital Organs 55

56. Male Genital Organs 56

57. Paired , posterior to urinary bladder Tubular (~ 5 cm) They secrete a thick alkaline fluid with fructose, and a coagulating agent Blood supply : inferior vesical and middle rectal arteries and vein seminal glands 57

58. It is approximately 2 cm x 3 cm x 4 cm in size and weighs about 20 g Covered by indestinict , richly vascularized, dense irregular collagenous fibromuscular capsule The glandular part makes up approximately two thirds of the prostate; the other third is fibromuscular Prostatic urethra Prostate 58

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61. Arteries Branches of the inferior vesical and middle rectal arteries . Veins prostatic venous plexus - are valveless Have Many connections with the valveless vertebral veins Nerve Supply Inferior hypogastric plexuses 61 Neurovascular supply

62. BPH (nodular hyperplasia ) 62

63. Pea size, paired, at base of penis Produce about 10% of semen Alkaline mucus buffers the acid that may be present in urine Bulbourethral gland (Cowper’s glands) 63

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65. Perineum is a diamond shaped region of trunk inferior to fascia of pelvic diaphragm A transverse line joining the anterior ends of the ischial tuberosities divides the perineum into two triangles: Urogenital triangle contains external genitalia Anal triangle contains the anal canal, anus and ischioanal fossa Perineum 65

66. 66 Surface anatomy and osseofibrous boundaries Perineum

67. Inferior pelvic aperture is closed by urogenital (UG) triangle - Urogenital diaphragm/ ( perineal membrane ) anal triangle - Pelvic diaphragm overlying ischioanal fat 67

68. Female Perineum 68

69. Is a fibromuscular mass located in the center of the perineum is the site of convergence and interlacing of fibers of several muscles, including the: Bulbospongiosus . External anal sphincter. Superfi cial and deep transverse perineal muscles. Smooth and voluntary slips of muscle from the external urethral sphincter , levator ani , and muscular coats of the rectum. Perineal body (central tendon of the perineum) 69

70. Anteriorly, the perineal body blends with the posterior border of the perineal membrane and superiorly with the rectovesical or rectovaginal septum 70 Perineal body…

71. The perineal fascia consists of superficial and deep layers deep perineal pouch Triangular, a trilaminar teaching view Lies between the superior and inferior fasciae ( perineal membrane) of the urogenital diaphragm (Contains deep transverse perineal muscle and the sphincter urethrae, intermediate part of the urethra ) 71 Fasciae and Pouches of Urogenital Triangle

72. is continuous with the deep fascia covering the external oblique muscle and the rectus sheath. i s also attached laterally - the ischiopubic rami Anteriorly - is fused to the suspensory ligament of the penis 72 perineal membrane

73. Lies between the perineal membrane and superficial perineal fascia ( Colles ' fascia). Contains Root (bulb and crura ) of the penis and associated muscles ( ischiocavernosus and bulbospongiosus ). Proximal (bulbous) part of the spongy urethra. Superfi cial transverse perineal muscles. Deep perineal branches of the internal pudendal vessels and pudendal nerves. 73 Superficial perineal space (pouch )

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75. The subcutaneous tissue of the perineum In males, the fatty layer is greatly diminished in the urogenital triangle, being replaced altogether in the penis and scrotum with smooth ( dartos ) muscle. is continuous posteriorly with ischio -anal fat pad 75

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77. rupture of the intermediate part of the urethra from separation of the pubic symphysis and puboprostatic ligaments rupture of the spongy urethra straddle injury 77 Clinical correlations Sleeve Hematoma

78. 78 Clinical correlations

79. The male perineum includes external genitalia (urethra, scrotum, and penis) perineal muscles anal canal Testes and epididymis considered internal genital organs on the basis of their developmental position and homology with the internal female gonads (ovaries) Male Perineum 79

80. Scrotum consists of Skin , fascia Dartos muscle (smooth) Tunica vaginalis Median raphé Allows the testes to remain ~3°C cooler than core temperature Involuntary contraction of dartos and cremaster muscles ( cremasteric reflex) in response to cold or sexual arousal Blood supply: Anterior scrotal, Posterior scrotal arteries and veins Scrotum 80

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82. Develop adjacent to kidneys Descend into scrotum through inguinal canal (function of gubernaculum testis ) before birth Blood Supply via gonadal arteries Parietal peritoneum is carried along lining of scrotum Spermatic cord: bundle containing all the “duct work” Testes 82

83. Clinical correlations Undescended testicle Testicular torsion 83

84. Head-superior , receives spermatozoa Body-distal and inferior Tail-leads to ductusdeferens Functions: Monitors and adjusts tubular fluid Recycles damaged spermatozoa Stores sperm and facilitates maturation (capacitation) Epididymis 84

85. Can be palpated as it passes over the pubic brim. spermatic cord 85

86. consists of a root, body, and glans . Prepuce = foreskin –partially covers glans and surrounds external urethral meatus(removed in circumcision) Preputial glands -produce smegma Penis 86

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88. Shaft (Body) of penis Corpus Cavernosum (2) Corpus Spongiosum Penile Urethra tunica albuginea Dorsal Artery and Vein deep fascia of the penis (Buck fascia ) – continuation of the deep perineal fascia Superficial ( dartos ) fascia 88

89. Prostatic Intermediate (membranous) Spongy (penile) Male urethra 89

90. 90 Clinical Hypospadias PARAPHIMOSIS

91. Moore clinically oriented anatomy 7 th Ed Grays anatomy, the anatomical bases of clinical practice, 40 th Ed Atlas of Human anatomy, Frank H. Netter MD, 6 th Ed Grays atlas of Anatomy 2 nd Ed BRS, Gross Anatomy 6 th Ed Clinical anatomy, Richard S. Snell, 9 th Ed Reference 91

92. Thank You!! 92