1. Anatomy of urinary bladder & urethra
R.Arulmoli

2. Learning outcomes
Explain the location,apex,base,surfaces and relations of the urinary bladder.
Describe the trigone of the urinary bladder.
Explain the supports,blood supply,nerve supply and lymphatic drainage of the urinary bladder.
Explain the prostatic,membranous and penile parts of male urethra.
Discuss the relations,blood supply,nerve supply,lymphatic drainage and surgical anatomy of male & female urethra.

3. Urinary bladder

4. Urinary bladder It is a hollow muscular organ.
Which serves as reservoir of urine.
Discharge urine periodically. 4

5. Urinary bladder- Location
Empty bladder is in the anterior part of pelvic cavity.
When it gets filled it becomes abdomino pelvic organ,reaching upto the umbilicus or even higher.
Normal capacity of bladder is about cc. 5

6. Urinary bladder- Capacity
Normal capacity of bladder in an adult is about cc.
Filling of urine beyond 220 cc causes a desire to micturate and bladder is usually emptied when filled about 250 cc.
Filling up to 500 cc is tolerated but beyond this becomes painful. Refered pain is felt in the lower part of anterior part of anterior abdominal wall, perineum and penis. 6

7. Urinary bladder- Parts
Empty bladder is pyramidal in shape.Parts:
4 angles -Apex ,base, two lateral angles.
4 surfaces – Superior, posterior and 2 inferolateral.
4 borders – Posterior, anterior, 2 lateral borders.
Full bladder is oval in shape. 7

8. Urinary bladder - Relations
Apex is connected to umbilicus by urachus (obliterated allantoic diverticulum).
Neck is continuous with urethra. In males it rests on upper surface of prostate.In females to urogenital diaphragm.
Lateral angles are pierced by ureters. 8

9. Urinary bladder - Relations
Superior surface - in males entire superior surface is covered by peritoneum.
In females - Anterior 2/3 is covered by peritoneum.
Posterior 1/3 is not covered by peritoneum and related to supravaginal part of cervix. 9

10. Urinary bladder - Relations
Inferolateral surfaces are related pelvic floor.
Between bladder and pubis there is a space called retropubic space filled with retropubic fat. 10

11. Urinary bladder - Relations
Posterior surface - in male, upper part of this surface is covered by peritoneum and related to rectovesical pouch
Lower part is not covered by peritoneum and related to seminal vesicle and vas deferens.
In female whole of this surface is related to anterior wall of vagina. 11

12. Urinary bladder - Relations12

13. Urinary bladder – Relations:
Applied anatomy:
Distended bladder anteriorly displaces parietal peritonium in the supra pubic region.
Supra pubic cystostomy can be done without disturbing the peritoneum. 13

14. Interior of bladder
The mucous is thrown into folds which get obliterated when the bladder is full .
Small triangular area over the lower part of base of bladder,mucosa is smooth (no folds) due to its firm attachment to muscular coat.This area is called trigone.
It is pink in color. In the upper lateral angles ureters open.
In the inferior angle there is internal urethral orifice.
Uvula vesicae is a slight projection posterior to urethral orifice formed by middle lobe of prostate. 14

15. Ligaments of bladder
Ligaments support the bladder. Two types. True & false.
True ligaments: Thickened pelvic fascia.
Lateral true ligament – attached from side of bladder to lateral pelvic wall.
Posterior true ligament – attached from lateral borders of base of the bladder to lateral wall
Medial & lateral puboprostatic ligaments (pubovesical in female) – attached from body of pubis to prostate.
Median umbilical ligament – formed by urachus. 15

16. Ligaments of bladder False ligaments: Peritoneal folds.
Median umbilical fold - peritoneal fold raised by urachus.
Two lateral umbilical folds - raised by obliterated umbilical arteries.
Lateral false - peritoneal fold raised by lateral true ligaments.
Posterior false - peritoneal fold raised by posterior true ligament. 16

17. Urinary bladder - Blood supply
Arterial supply:
Main arterial supply - Superior and inferior vesical arteries arise from the anterior trunk of internal iliac arteries.
Additional arterial supply - Obturator and inferior gluteal arteries. In the female uterine and vaginal arteries.
The inferior vesical artery in female is called vaginal artery.
Venous drainage:
Drained by vesical venous plexus lying on the inferolateral surfac.Veins from this plexus drains into internal iliac veins. 17

18. Urinary bladder - Lymphatic drainage
Mainly drain into external iliac lymph nodes.
Some to internal iliac lymph nodes.

19. Urinary bladder - Nerve supply
Vesical nerve plexus consists of sympathetic and parasympathetic component.
Parasympathetic from (nervi erigentes) S2 3 4 supplies motor fibers to detrusor muscle and inhibitory to the sphincter vesicae.
Sympathetic nerves supply motor fibers to sphincter vesicae and inhibitory to the detrusor muscle .
Voluntary motor control of external sphincter is by pudendal nerves.

20. Urinary bladder - Applied anatomy
Ectopia vesicae
Distended bladder
Cystoscopy
Suprapubic cystostomy
Neurological lesions of bladder
Autonomous neurogenic bladder
Atonic bladder
Automatic or Reflex bladder 20

21. Ectopia Vesicae

22. Suprapubic cystostomy

23. Urethra 23

24. Male urethra
It is a tubular passage from neck of bladder to the external urethral meatus.
It is 20 cm in length.
When penis is hanging it presents ‘S’ shaped curvature.
It has 3 parts :
1. Prostatic part – 3 cm
2. Membranous part – 2 cm
3. Penile or spongy part – 15 cm. 24

25. Prostatic urethra
Extends from neck of urinary bladder. It passes through prostate. Widest and most dilatable part.
Posterior wall of prostatic urethra presents:
In the upper half in the midline there is a vertical ridge of mucous membrane called urethral crest.
Colliculus seminalis is an elevation in the middle of the urethral crest into which the prostatic utricle opens.
On either side of the prostatic utricle opening the ejaculatory ducts opens. 25

26. Prostatic urethra 26

27. Membranous part It is second part.
It passes through urogenital diaphragm to enter bulb of penis.
It is shortest , narrowest and least dilatable part.
It is surrounded by sphincter urethrae and bulbourethral glands are posterolateral to this part.

28. Spongy or penile part It is 15 cm in length.
Passes through the bulb and corpus spongiosum of penis.
Opens at external urethral meatus on the tip of glans penis. 28

29. Spongy or penile part Shows two dilatations:
1. Bulbar fossa present in the first 4 cm of corpus spongiosum.
2. Second is the navicular fossa in the glans penis. 29

30. Spongy or penile part
Ducts of bulbourethral glands (Cowper’s glands) open after 2.5 cm from its commencement.
Numerous urethral glands (Littre glands) open into the penile urethra.
There are lacunae present in the penile urethra.Largest is lacuna magna (sinus of guerin) in roof of fossa navicularis. 30

31. Sphincters of urethra There are two sphincters.
Internal sphincter at the neck of the bladder consist of smooth muscle. Supplied by sympathetic nerve.
External sphincter made of skeletal muscle in the membranous part of urethra supplied by pudendal nerve.

32. Male urethra - Epithelium
Up to opening of ejaculatory ducts - transitional epithelium.
Near external urethral orifice - stratified squamous epithelium.
In between - stratified columnar epithelium. 32

33. Blood supply Arterial supply:
Prostatic & membranous part - inferior vesical and middle rectal arteries.
Penile part - Arteries of bulb of penis from internal pudendal artery.
Venous drainage by corresponding veins.

34. Nerve supply
Perineal branches of pudendal nerves.

35. Lymphatic drainage
Prostatic & membranous part - Internal and external Iliac lymph nodes.
Penile part - Deep inguinal and superficial inguinal nodes. 35

36. Catheterization 36

37. Congenital anomaly - Hypospadiasis
Failure of the fusion of Urethral or urogenital folds ventrally lead to hypospadias (urethra opening ventrally)

38. Congenital anomaly - Hypospadiasis
Due to failure of fusion of urethral folds.
Urethra opens on the ventral surface at different levels. 38

39. Female urethra
4 cm in length. Female urethra corresponds to male urethra of prostatic part proximal to opening of prostatic utricle.
It begins at the internal urethral orifice 5 cm behind pubic symphysis,runs downwards,embedded in the anterior wall of vagina.
Traverses urogenital diaphragm and ends at the external urethral orifice in the vestibule surrounded by sphincter urethra.
Numerous mucous glands (paraurethral glands of Skene) open into the female urethra. 39

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