Pelvis

The pelvic cavity

The sigmoid colon : is about 25-40 cm long ,starts in front of the pelvic brim & terminate opposite to the 3rd sacral vertebra to become the rectum .It is attached to the posterior wall of pelvis by sigmoid mesocolon & is related anteriorly to the urinary bladder in the male & to the uterus & upper vagina in the female.
The sigmoid is supplied by the sigmoid branches of the inferior mesenteric Artery, venous drainage to the portal vein & lymphatic drainage is to the inferior mesenteric lymph nodes, while innervated from the hypogastric plexus.
The rectum: is about 12-15 cm long, starts opposite to the 3rd sacral vertebra & terminates in front of the tip of the coccyx by piercing the pelvic diaphragm & becomes as anal canal & its lower part is dilated as rectal ampulla .At the junction with the anal canal there is a sling like structure, known as anorectal ring .The upper 13 of the rectum is covered by peritoneum on its anterior & lateral surfaces, the middle 13 covered anteriorly only, while the lower 13 devoid of any peritoneal covering as extraperitoneal structure.
Relations:
Anteriorly in male, upper 23 is related to sigmoid colon, lower 13 to posterior surface of bladder, while in female lower 13 is related to vagina.
Posteriorly to sacrum, coccyx, piriform & pelvic diaphragm.
Superior rectal from inf. Mesenteric A.
Middle rectal from internal iliac A.
Inferior rectal from internal pudendal A.
Superior rectal from inf. Mesenteric A.
Middle rectal from internal iliac A.
Inferior rectal from internal pudendal A.

Blood supply:

1-Superior to portal V.
2-Middle & Inferior to internal pudendal V.
1-Superior to portal V.
2-Middle & Inferior to internal pudendal V.


Veins:

Lymphatic to pararectal & innervated by Inferior Hypogastric plexus

The urinary bladder
Lies behind the pubic bone within the pelvis when empty, as become filled it rises into the hypogastric region. The empty bladder is pyramidal having apex, base, superior & 2 inferolateral surfaces in addition to the neck.
-Apex behind pubic symphysis & is connected to umbilicus by median umbilical ligament (remnant of urachus).
-The base (posterior surface) we can see the 2 vas deference lie side by side & separating the 2 seminal vesicles from each other, we can see also the ureter crossing the vas deference to enter the bladder. Only the upper part of posterior surface is covered by peritoneum. The lower part of the posterior surface is separated from the rectum by rectovesical pouch in the male.
-Superior surface is covered by peritoneum & may reach the umbilicus where is completely filled. It is related to coils of ileum or sigmoid & in female is related to the vagina & is separated from it by uterovesical pouch.
-The inferolateral surfaces are related to the retropubic space containing pad of fat.
-The neck faces inferiorly & is applied to the base of the prostate & is fixed in position by the puboprostatic ligament in the male & pubovesical ligament in the female.
Once opened the base from inside shows a smooth mucosa without folds known as trigon with 3 angles. The upper 2 lateral angles for the entrance of the ureters, while the inferior angle leads to the internal urethral orifice leading to the prostatic urethra.
There is inter-ureteric crest extends between the openings of the 2 ureters & immediately behind the internal urethral orifice there is an elevated area known as Uvula vesicae caused by the middle lobe of the prostate.

The bladder is supplied by superior & inferior vesical As., while venous drainage leads to vesical venous plexus goes to internal iliac vein & lymphatics leads to both the internal & external iliac nodes.
The nerve supply: by inferior hypogastic plexus, whose sympathetic component from L1-L2 sympathetic ganglion, while parasympathetic from pelvic splanchnic N.
The sympathetic inhibits contractions of detrusor Ms. of the wall & closes the sphincter vesicae at the neck.
Parasympathetic stimulates contractions of detrusor Ms & opens the sphincter vesicae leading to passage of urine (Micturition).

The prostate

Fibromuscular glandular structure of about 3 cm long lying between neck of bladder & urogenital diaphragm. The base faces superiorly around the neck of the bladder, while its apex faces inferiorly & rests on the urogenital diaphragm, is traversed by the prostatic urethra from base to apex & its upper posterior surface on each side is pierced by the ejaculatory duct to open into the prostatic urethra.
The capsule is connected to posterior surface of pubic bone by the pubo-prostatic ligament.
It consists of 5 lobes, an anterior lobe in front of the prostatic urethra, median (middle) encloses between the urethra & the 2 ejaculatory ducts & its upper surfaces is projected as uvula of bladder in the region of the trigon, above the internal urethral opening, the posterior lobe behind the prostatic urethra & below the ejaculatory ducts. The right & left lobes lie on either side of the urethra.


Relations:
-Anteriorly: is related to the pubic symphysis by extraperitoneal fatty tissue in the retropubic space as cave of Retzius. It is also connected to back of the pubic bones by puboprostatic ligament.
-Posteriorly is related to ampulla of the rectum & is separated from it by rectovesical septum.
-Laterally on each side by levator ani muscles.

The ovary

Is about 4 x 2 cm & attached to the back of broad ligament by the mesovarium. The suspensory ligament of the ovary is the part of broad ligament between the attachment of the mesovarium & lateral wall of the pelvis, while the round ligament of the ovary represents the remnant of the upper part of gubernaculum & is connects the ovary to the lateral margin of the uterus.
The ovary lies in the ovarian fossa against the lateral wall of the pelvis. The fossa is bounded by external iliac vessels above & internal iliac vessels behind.
The ovary is supplied by ovarian A. arises from abdominal aorta at the level of L1 vertebra & is drained to I.V.C on right side, but to left renal vein on the left side. Lymphatics to para-aortic nodes at L1 vertebra. It is innervated by fibers from aortic plexus along the ovarian artery.

The uterine tubes

Each of tubes is about 10cm lying in the upper border of the broad ligament, they connect the peritoneal cavity at the region of the ovary to the uterine cavity. They include:
1-Infundibulum, projects beyond the broad ligament & has a finger like processes known as fimbriae.
2-Ampulla, is the widest part of the tube.
3-Isthmus, is the narrowest part.
4-Intramural part, which pierces the uterine wall.
The uterine tubes are supplied by the uterine A. & by a branch from the ovarian artery & lymphatic drainage into the internal iliac & para-aortic nodes.
The uterus
Pear-shaped structure measuring 3 x 2 x 1 inches consists of fundus, body, and cervix.
The fundus: is the part above the entrance of uterine tubes.
The body: extends below the entrance of the 2 uterine tubes to the cervix. It is hollow from inside as uterine cavity.
The cervix: connects the uterine cavity to the vagina & includes supravaginal & vaginal parts. The canal of the cervix communicates with the cavity of the uterus by internal os & with the vagina by the external os.
Normally the uterus is antiverted-antiflexed, where long axes of the uterus bent forward on the long axis of the vagina is the antiversion, where uterus bent forward with long axis of cervix (at level of internal os) is antiflexion.
If the fundus & body bent backward on the vagina it is called retroverted.
Blood supply by 1-Uterine A. 2- Cervical branch of ovarian A.
Lympahtics: 1- From fundus drains to para-aortic via ovarian vessels 2-From body & cervix into internal & external iliac nodes. 3-some to inguinal nodes along round ligament of the uterus via the inguinal canal.
Supports of uterus
Levator ani Ms & the perineal body:
Some fibers of levator ani are inserted into the perineal body & this support the uterus in addition to the tone levator ani.
Condensations of pelvic fascia forming 3 important ligaments as;
a . Transverse cervical (cardinal) ligament passes between cervix & upper end of the vagina.
b . Pubocervical ligament between posterior surface of pubis & cervix.
c . Sacrocervical ligament from lower end of the sacrum to the cervix & upper end of the vagina.
The round ligament of the uterus:
Represents the remnant of the lower half of gubernaculum, it extends between the superolateral angle of the uterus to the inner surface of labia majora, passing through the inguinal canal.
Broad ligament of the uterus extends between lateral borders of the uterus to the lateral pelvic wall. It includes mesovarium, suspensory ligament of the ovary & mesosalpinx.