Anatomy of genitourinary system
- 1. Anatomy of genitourinary system Dr. Kishor Bhattarai 1st year resident Department of Radiodiagnosis,NAMS
- 2. Overview • Anatomy renal system and common variants • Anatomy of male and female reproductive organs and common variants
- 3. Kidney,ureter,bladder and urethra • The kidney functions to maintain electrolyte homeostasis and waste excretion • empty medially into ureters,which courses inferiorly into the pelvis and enter the bladder • urine is temporarily stored in bladder till it is cleared via urethra
- 4. Kidneys • on either side of lower thoracic and upper lumbar spine • usual location - upper border of 12th thoracic vertebra and lower border of 3rd lumbar vertebra • right is slightly lower than the left (2cm) • long axis is directed downwards and laterally-upper poles lie nearer to the median plane • lower pole is 2-3 cm anterior to the upper pole
- 5. kidneys • bean shaped • poles upper-broad due to adrenal gland lower -pointed • borders lateral- convex medial-concave with hilum • surfaces anterior- irregular posterior - flat
- 6. • normal size in adults : 10-15 cm • right kidney is shorter than the left normally but not by more than 1.5cm • size is approximately three and a half lumbar vertebra and their associated discs on a radiograph
- 7. Anterior relations of kidney • right right adrenal gland liver 2nd part of duodenum hepatic flexure of colon small intestine • left left adrenal gland spleen stomach pancreas splenic flexure jejunum
- 8. Posterior relations of kidney • right -diaphragm - medial and lateral arcuate ligaments muscles psoas major quadratus lumborum transvese abdominis blood vessels subcostal vessels iliohypogastric nerve ilioinguinal nerve 12th rib • left -diaphragm - medial and lateral arcuate ligaments muscles psoas major quadratus lumborum transvese abdominis blood vessels subcostal vessels iliohypogastric nerve ilioinguinal nerve 11th and 12th rib
- 10. Fat and fascia surrounding the kidney • fibrous capsule covers the kidney • perirenal fat layer of fat surrounding the fibrous capsule and also filling up areas in renal sinus • renal fascia fibroareolar sheath over the condensed fat • pararenal fat surrounds the renal fascia,more abundant posteriorly
- 11. Internal structure • outer cortex cortex arches over the bases of pyramids and renal column of bertin that separates medulla into pyramids • inner medulla consists 8-16 pyramids the apex of each pyramid projects into a calyx as a renal papilla
- 12. Renal collecting system • pappilae positioned in the apex of pyramids drains into the fornix of minor calyces • they join to form 3 -4 major calyces • major calyces join to form renal pelvis • the renal pelvis drains into the muscular tube called ureter
- 13. Extrarenal pelvis • normal variant of pelvis having pelvis outside the confinement of renal hilum • more distensile than the intrarenal pelvis thus it may be confused for proximal hydroureter
- 14. Retroperitoneal space • lies between the posterior parietal peritoneum and anterior to the transversalis fascia • divided into three spaces by the perirenal fascia anterior pararenal space perirenal space posterior pararenal space
- 15. Anterior pararenal space • it is bounded by anteriorly: posterior parietal peritoneum posteriorly: Gerotas’fascia laterally: lateral conal fascia superiorly:diaphragmatic fascia inferiorly:pelvic brim
- 16. Contents • pancreas and retroperitoneal portion of duodenum centrally • ascending colon on right • descending colon on left
- 17. Perinephric space • space between anterior Gerota’s and posterior Zuckerandal fascia • laterally fuse to give lateral conal fascia • superiorly anterior fascia blends with right inferior coronary ligament near bare area of liver while posterior fascia blends with diaphragmatic fascia • medially blends with the connective tissue surrounding great vessels • inferiorly relatively open to retroperitoneal space of abdomen and pelvis
- 18. Contents • The perinephric space contains kidneys adrenal gland proximal collecting system renal vasculature perirenal vascular network lymphatics prominent amount of fat which are septated The largest fat accumulation in perirenal space is medial to the lower pole of the kidney,this is the preferential location where abscesses,hematomas and urinomas may accumulate
- 20. Posterior pararenal space • space between the posterior perinephric fascia and adjacent transversalis fascia • contains only fat
- 21. Renal vasculature • renal venous drainage renal veins drain into inferior venacava they lie anteriorly to arteries in renal pelvis left renal vein is longer and passes anterior to aorta before draining into the inferior venacava the left gonadal vein drains into left renal vein while right gonadal vein drains directly into the inferior venacava
- 22. Renal arteries • branches from abdominal aorta laterally between L1 and L2 below the origin of superior mesenteric artery • right renal artery is longer, higher/same level compared left renal artery and passes posterior to ivc • both renal arteries usually have two divisions one passes posterior to renal pelvis and supplies posterior upper part of the kidney another anterior branch supplies upper anterior and entire lower kidney • within the hilum ,devide into five segmental branches as interlobar arteries (in between the lobes/pyramids)-arcuate arteries( at CMJ and the base of pyramids)-interlobular arteries(run into capsule)
- 24. transverse image of right renal artery as it extends from the aorta on longitudinal scan of the ivc and aorta , the right renal artery can be seen as a circular structure posterior to the inferior venacava
- 26. Accessory renal artery • initially the kidneys are suplied by lateral sacral branches of aorta • during ascent from pelvis they acquire successively higher lateral branches of aorta upto the definitive renal arteries at the level of L1-L2 • failure of regression of inferior arteries give rise to accessory renal arteries
- 27. Brodel’s avascular plane • The avascular plane of of brodel is the section of renal parenchyma between 2/3rd anterior and 1/3rd posterior kidney on cross section • the reason for its relative avascularity is that it represents the plane where the anterior and posterior segmental renal artery branches meet • it is located just posterior to lateral convex border of the kidney and permits a relatively safe access route to the pelvicalyceal system for nephrostomy
- 29. Renal anatomical variation • persistent fetal lobulations due to incomplete fusion of developing renal lobules seen as smooth indentations of renal outline
- 30. • Dromedary hump local bulge /covexicity along lateral border of the left kidney it is due to impression of spleen or fetal lobulation
- 32. Junctional parenchymal defect • due to due to incomplete fusion of renal lobes • located between upper and mid poles of the kidney • typically triangular in shape
- 33. • Hypertrophied column of Bertin Columns of Bertin represent the extension of renal cortical tissue which separates the pyramids They become of radiographic importance when they are unusually enlarged and may be mistaken for a renal mass.
- 34. Ureters • 25-30 cm and 2-8 mm in in diameter • it has 4 parts pelvis abdominal pelvic intravesical
- 35. Pelvis course • passes behind the second part of duodenum
- 36. Abdominal Course • retroperitoneal • right and left ureter lie laterally to ivc and aorta respectively • it passes vertically anteriorly on medial edge of the psoas muscle which separates it from transverse process of lumbar vertebra (L2-L5)
- 37. Pelvic part of ureter • ureter crosses the front of bifurcation of common iliac artery to reach the pelvis • descends downward and backward along the lower border of internal iliac artery • then it curves forward and medially to reach the bladder
- 38. Close to the bladder • male passes above seminal vesicle and crossed by vas deferens • female passes under uterine artery in the base of broad ligament close to the lateral fornix
- 39. Areas of constrictions • Ureteropelvic junction(PUJ) • Bifurcation of common iliac artery • Ureterovesical junction(VUJ)
- 40. Vascular supply of ureter • receives from different arteries along its descending course renal artery branches gonadal artery branches abdominal aorta internal iliac superior vesical uterine middle rectal vaginal inferior vesical • venous drainage is via corresponding renal,gonadal and iliac veins
- 42. Urinary bladder • hollow muscular vesicle for storing urine temporarily • higher in position in children and slightly higher in males than females • pyramidal shaped organ when empty and oval when filled • triangular base posteriorly,an apex behind the symphysis pubis ,one superior and two posterolateral surfaces • separated from the pubic symphysis by the retropubic fatty space of Retzius
- 45. Peritoneal reflection • located only on superior surface of the bladder males:entire superior surface is covered by peritoneum females: anterior 2/3rd covered posterior 1/3rd uncovered,related to supravaginal part of cervix
- 46. Mobility and support of bladder • bladder is usually free to move except in neck region which lies 3-4 cm from pubic symphysis due to ligaments males : puboprostatic ligments females: pubovesicle ligaments
- 47. Blood supply and lymphatics of bladder • arterial suppy via superior and inferior vesicle artery • venous drainage via vesical venous plexus to internal iliac vein • lymphatics along the blood vessels mainly via external iliac and then para-aortic nodes
- 48. Male urethra • approx. 20 cm in length • from internal urethral spincter at the neck of bladder to the external urethral orifice at the tip of penis • divided into posterior urethra- prostatic and membranous part anterior urethra-penile urethra/spongy urethra • protatic urethra is the widest part appx. 3cm in length and receives ejaculatory duct • membranous urethra is the shortest and narrowest part appx 1.5cm • penile urethra is the longest (14-15 cm)
- 51. Female urethra • 4cm long • from internal urethral spincter at bladder of neck through the urogenital diaphragm ending at the external urethral meatus in the vestibule of external genitalia • multiple tiny urethral glands open into the lower urethra(homologus to the prostate in males)
- 52. Spincters in female urethra • no true spincters( prone to incontinence) internal urethral spincters: due to decussation of vesicle muscle at urethrovesical junction involuntary muscles of urethral wall inner longitudinal middle circular outer striated(rhabdospincter) external urethral spincter at urogenital diaphragm ,less developed as compared to male
- 53. The male reproductive organs • consists of prostate seminal vesicle testis, epididymis, vas deferens and spermatic cord penis
- 54. Prostate • it is shaped like upside down truncated cone and surrounds the base of the bladder and proximal urethra, extending inferiorly to the urogenital diaphragm and external spincter • it has a base related to the bladder above an apex inferiorly sitting on the pelvis (urogenital diaphragm)
- 55. anterior wall which is separated from the pubic symphysis by retropubic fatty space of retzius posterior wall related to the rectum 2 inferolateral walls related to the muscles of pelvic sidewalls
- 56. • fascia known as denoviller’s fasccia separates prostate and seminal vesicle from rectum • puboprostatic ligament provides support • fibrous sheath derived from the pelvic fascia surrounds the prostate gland
- 57. Zonal anatomy of the prostate • peripheral • central • transition for radiological purpose central and transitional zone cannot be distinguished so entire inner gland is usually referred to central gland
- 58. transrectal usg image showing prostate gland
- 59. Seminal vesicle • paired sacculated divertiicula that lie transversely behind the prostate and store seminal fluid • these convulated tube narrow at their lower end to fuse with the vas deference to become ejaculatory duct.
- 60. Blood supply of prostate and seminal vesicle • arterial supply: from internal iliac arteries via inferior vesicle artery • venous drainage via prostatic venous plexus prostatic venous plexuses communicates with the internal vertebral venous plexuses providing a potential route for spread of prostatic cancer
- 61. lymphatic drainage • accompany blood vessels to internal illiac and sacral nodes
- 62. The testis, epididymis and spermatic cord The testis • oval sperm producing gland having upper and lower pole • size: adult dimension approximately 5*3*2cm • suspended by spermatic cord in scrotal sac • covered by fibrous capsule called the tunica albuginea
- 63. • tunica is thickened posteiorly and forms a fibrous septa known as mediastinum testis • fibrous septa divides the testis into lobules • 200-400 lobules contain sperm producing cells which are drained by seminiferous tubules • seminiferous tubules converge into mediastinium testis forming 20-30 larger ducts
- 64. • larger ducts forms a network of channel within the stroma known as rete testis • from here 10-15 efferent ductules convey sperm to the head of epididymis • testis and epididymis are invaginated anteiorly into double layered serous covering, the tunica vaginalis • tunica vaginalis is continuous with peritoneum during development via the processus vaginalis which is obliterated at birth
- 65. Blood supply • artery: via testicular artery which arises directly frrom the aorta below the level of renal arteries • venous drainage: via pampiniform plexus • lymphatic drainage: para-aortic nodes
- 66. The Epididymis • convulated sperm duct intimately related to testis having head: lying on upper pole of testis body: along posterolateral aspect of testis tail: lying inferiorly
- 67. The Vas Deferens • sperm duct extends from tail of the epididymis through scrotum, inguinal canal and pelvis to fuse with the duct of seminal vesicles to form ejaculatory duct in prostate gland
- 68. Spermatic cord • it is the bundle of nerves, duct and blood vessels connecting testicles to the abdominal cavity
- 69. Contents • 3 arteries testicular artery artery to ductus deferens cremasteric artery • 3 nerves genital branch of genitofemoral cremasteric autonoic nerves • 3 other structures ductus deferens pampiniform plexus lymphatics
- 70. The penis • comprises of 3 cylinders of endothelium lined erectile tissue arising from the perineum a ventral corpus spongiosum surrounding urethra paired dorsal corpora cavernosa
- 71. Blood supply • arteries via paired deep dorsal and cavernosal artery arising from pudendal artery • venous drainage via paired dorsal vein
- 72. The female reproductive tract • Consists of Vagina Uterus Uterine tubes Ovaries
- 73. Vagina • it is a musular canal extending from uterus to the vestibule • the cervix invaginates the upper vagina and arbitarily divides it into shallow anterior, deep posterior and lateral recesses or fornices
- 74. Blood supply • arterial supply: via vaginal branch of internal iliac and uterine artery • venous drainage: via plexus in lateral wall to the internal iliac vein • lymphatic drainage upper 2/3rd: via internal and external iliac nodes lower 1/3rd: via superficial inguinal nodes
- 75. Uterus • pear shaped muscular organ lying between the bladder and rectum • it has fundus body cervix • the uterine tubes open into cornua of the uterus superolaterally • the uterus leads to vagina via the cervical canal • internal os: is at upper end of the cervical canal • external os: at its lower end
- 76. Peritoneal reflections • peritoneum covers the fundus body and upper part of the vagina posteriorly and reflected on anterior surface of the rectum forming the pouch of douglas • anteriorly peritoneum is reflected from upper part of the body to the superior surfae of the bladder • on either side of the uterus the peritoneum is reflected to the lateral pelvic walls covering the fallopian tubes. the folds of peritoneum so formed is called the broad ligament
- 77. Ligamentous support of uterus • these condensations of endopelvic fascia anchor the cervix to the walls of pelvis and comprise of pubocervical ligament transverse cervical ligaments uterosacral ligaments
- 78. Normal variants of uterus • retroverted uterus uterus axis lie in posterior plane with the axis of cervix directed upward and backwards. • retroflexed uterus cervix bears the usual relationship with vagina but the uterus is bent backward on the cervix
- 79. MR image depicting the retroverted uterus
- 80. The uterine tubes lies in upper free edge of the broad ligament and covey ova from the ovaries to the uterus • 4 parts infundibulum isthmus ampulla intrauterine part
- 81. Blood supply of uterus and uterine tubes • arterial supply via uterine artery,a branch of internal iliac runs medially in the base of broad ligament ascends tortuously within the broad ligament to supply the uterus and tubes • venous drainage via plexus in base of broad ligament to internal iliac vein
- 82. Lymphatic drainage • uterine fundus para-aortic nodes • uterine body via broad ligament to external iliac nodes • cervix external and internal iliac nodes
- 83. Ovaries • paired oval organ measuring appx. 3 x 2 x 2 cm • oriented vertically on posterior surface of broad ligament in close contact with infundibulum • surface is not covered by peritoneum • has tough outer layer: tunica albuginea
- 84. supports of ovary • mesovarium attaches anterior surface of the ovary to posterior surface of broad ligament • ovarian ligament attaches lower pole of ovary to the uterus • suspensory ligament of ovary attaches upper pole of ovary to pelvic side wall
- 85. Blood supply and lymphatic drainage • arterial supply via ovarian artery arises directly from aorta at L2 • venous drainage via right ovarian vein into ivc via left ovarian vein into left renal vein • lymphatic drainage along the ovarian vessels to paraaortic nodes
- 86. References • Anatomy for Diagnosting Imaging 3rd edition: Stephanie Ryan • Textbook of Radiology and Imaging 7th edition: David Sutton • www.radiopedia.org • Various internet resources for images
- 87. Thank you