Urinary bladder

Hello friends..you can use these notes for your convenience as they are taken from many other standard books ( like A.K.D, V.Singh, B.D.C.). Thank you

1. URINARY BLADDER DR. VIBHASH KUMAR VAIDYA DEPARTMENT OF ANATOMY

2. INTRODUCTION The urinary bladder is a muscular reservoir of urine, lying in the anterior part of the pelvis. It is commonly involved in clinical conditions such as retention of urine, cystitis (inflammation of the urinary bladder), calculus, disorder of micturition , and cancer. Hence, its anatomy is of immense importance to clinicians.

3. LOCATION The urinary bladder is situated in the anterior part of the lesser pelvis immediately behind the pubic symphysis and in front of rectum in male and uterus in the female. When the bladder is empty it lies entirely within the lesser pelvis but when it becomes distended with urine, it expands upward and forward into the abdominal cavity.

4. SIZE AND SHAPE It is tetrahedral in shape when empty and ovoid in shape when distended. CAPACITY Normally in adult male the capacity varies from 120 to 320 ml. The mean capacity is about 220 ml. An amount of urine beyond 220 ml causes a desire to micturate but the bladder is usually emptied at about 250–300 ml . 2. The filling of urine up to 500 ml may be tolerated but beyond this, it causes pain due to tension of its wall. On collection of urine about 800 ml, the micturition is beyond one’s voluntary control.

5. EXTERNAL FEATURES AND RELATIONS 1. Apex. 2. Base. 3. Neck. 4. Three surfaces (superior and two inferolateral surfaces). 5. Four borders (anterior, posterior and two lateral).

6. APEX It provides attachment to the median umbilical ligament and lies posterior to the upper margin of the pubic symphysis .

7. BASE In the male: 1. Upper part is separated from rectum by the rectovesical pouch containing coils of the small intestine. 2. Lower part is separated from rectum by the terminal parts of vasa deferentia and seminal vesicles. 3. The triangular area between the vasa deferentia is separated from the rectum by rectovesical fascia (of Denonvilliers ). In the female, it is separated from the cervix of uterus and by the vesicouterine pouch .

8. NECK It is the lowest and most fixed part of the bladder. It is situated where the inferolateral and the posterior surfaces of the bladder meet. It is pierced by the urethra . Its relations are: In the male, it rests on the upper surface of the prostate where the smooth muscle fibres of the bladder wall are continuous with those of the prostate. In the female, it is related to the urogenital diaphragm.

9. SUPERIOR SURFACE In the male, it is completely covered by the peritoneum which separates it from: coils of the ileum , sigmoid colon . In the female, it is covered by the peritoneum except for a small area near the posterior border, which is related to the supravaginal part of the uterine cervix. Here the peritoneum is reflected on to the uterine isthmus forming vesicouterine pouch.

10. INFEROLATERAL SURFACES The inferolateral surfaces are devoid of peritoneum and in both male and female are related: In front to – retropubic space, – pubic symphysis , and – puboprostatic ligaments. Behind to – obturator internus muscle above, and – levator ani muscle below.

11. LIGAMENTS The ligaments of the bladder are of two types—true and false. Lateral ligaments (two in number, right and left) 2. Puboprostatic ligaments (four in number, two on each side—lateral and medial) 3. Median umbilical ligament 4. Posterior ligament (two in number, right and left) False Ligaments Anteriorly there are three folds Laterally a pair of false lateral ligaments Posteriorly a pair of false posterior ligaments

12. INTERIOR OF THE BLADDER

13. ARTERIAL SUPPLY superior and inferior vesical arteries which are the branches of anterior division of internal iliac arteries. Obturator and inferior gluteal arteries. Uterine and vaginal arteries in the female. VENOUS DRAINAGE The veins of the bladder do not follow the arteries. They form a complicated plexus on the inferolateral surfaces near the prostate called vesical venous plexus. 1. This plexus passes backward in the posterior ligaments of the urinary bladder to drain into the internal iliac veins. 2. It communicates: (a) In the male with the prostatic venous plexus. (b) In the female with the veins at the base of broad ligament.

14. NERVE SUPPLY

15. THANKS………