Urinary Bladder & Urethra

The urinary bladder & the urethra

Urinary bladder: • Temporary reservior of urine • Lies in the anterior part of the pelvic cavity • Varies in its size ,shape & position • When empty lies in the pelvis, • When it fills,it expands upward into the abdominal cavity

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Empty bladder – tetrahedral, Full bladder -ovoid Empty bladder has : an apex, a base, a neck, 3 surfaces( superior/rt & lt. inferiolateral) 4 borders( 2 lateral/anterior/posterior) A full bladder has: an apex, a neck 2 surfaces ( anterior/posterior)

Relations • 1. Apex: -connected to the umbilicus by the medial umbilical ligament • 2. Base: in females: -uterine cervix, & vagina in males: -upper part: coils of intestine -lower part: seminal vesicles & vas deferens

• 3.neck: -lowest and most fixed part of the bladder -lies 3-4 cms behind the pubic symphysis -piearced by the internal urethral orifice In males: -covered by the prostate In females: -pelvic fascia

• 4. Superior surface: In males: completely covered by the peritoneum sigmoid colon & coils of terminal ileum In females: peritoneum covers the greater part, except a small area near the posterior border( w/c is related to cervix) the peritoneum from the superior surface is reflected to the uterus forms vesicouterine pouch

• 5. Inferiolateral surfaces: - devoid of peritoneum - seperated from each other by the ant. border & from the sup. Surface by lateral borders. In males: -the pubis,puboprostatic ligament,retropubic fat,levator ani & obturator internus In females: -same,except that puboprostatic ligament replaced by pubovesical ligament. # as bladder fills inferiolateral sur = ant.surface

Ligaments of the bladder: • True ligaments • False ligaments

True ligaments • Around the neck and base of the bladder 1.lateral true ligament 2. lateral puboprostatic ligament 3. medial puboprostatic ligament 4.median umbilical ligament 5.posterior ligament

False ligaments • Peritoneqal folds w/c does not support the bladder 1.the median umbilical fold 2.the lateral false ligament 3.the median umbilical fold 4.the posterior false ligament

Interior of the bladder • In an empty bladder: greater part of the mucosa shows irregular folds traingular area over the lower part of the base,mucosa of w/c will be smooth. this area is known as TRIGONE OF THE BLADDER.

• Trigone of the bladder; -the apex of the trigone is directed downwards & forwards. Importance : -the internal urethral opening opens in to the apex. -the ureters opens at the posteriolateral angles of the trigone. -slight elevations just above the urethral opening-uvula vesicae.

Capacity • In an adult: 220 ml ( 120- 320 ml ) > 220 ml – desire to micturate > 500 ml - painful

Artery supply • Main: - superior vesical & inferior vesical artery • Additional : - obturator,inf. Gluteal - uterine & vaginal artery ( females)

Venous drainage • Internal ileac vein

Lymphatic drainage • External ileac nodes • Internal ileac nodes, lateral aortic nodes

Nerve supply • Parasympathetic S2- S4 • Sympathetic T11 – L2

Applied • Cystoscopy • Urinary incontinence

The urethra • Male urethra • Female urethra

The male urethra • Muscular tube • About 18-20 cms long • Conveys urine from internal urethral orifice – external urethral orifice • In the flaccid state – 2 curvatures, shape as ‘S’.

4 parts of the urethra • 1.Urethra in the bladder neck ( preprostatic urethra ) • 2. Prostatic urethra • 3.membranous urethra ( intermediate ) • 4.spongy urethra ( pelvic )

• 1.Urethra in the bladder neck: - preprostatic urethra - 1.5 – 2 cms - neck of the bladder – sup. Aspect of the prostate.

• 2. prostatic part: - 4 cms. Long - continuous with the urethra in the bladder neck - widest & most dilated part - more widest in its middle part Notable features: - urethral crest: - prostatic sinus - seminal colliculus - openings for the ejaculatory duct

• 3.membranous urethra: - 1.5 – 2 cms long - passes thru the external urethral sphincter - extends from the prostatic urethra – spongy urethra - narrowest & least distensible part - bulbourethral glands are placed one on each side.

• 4.spongy urethra: -penile part - longest part - 15 cms long - distal end of the membranous part of the urethra – external urethral orifice - passes thru the bulb of the corpus spongiosum of the penis -lumen 5 mm - expanded in the bulb of the penis ( intra bulbar fossa) & glans penis ( navicular fossa ) - ducts of bulbo urethral glands opens

Artery supply • Proximal 2 parts branches of the internal vesical & middle rectal arteries • Distal 2 parts branches from the internal pudendal artery

Lymphatics: • Internal ileac • External ileac • Deep inguinal

Female urethra • Anterioinferiorly from the internal urethral orifice- external urethral orifice • 4 cms long • Urethral glands are present

Artery supply • Internal pudendal and • Vaginal artery

lymphatics • Sacral and internal ileac

Applied • Catheterization • Urethritis • hypospadiasis

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