Transcript Pelvic Anatomy - Creighton University School of Medicine

Pelvic Anatomy
District I ACOG
Medical Student Education Module 2011
Gynecologic Viscera
Uterus: thick, muscular organ
Derived from the fusion of the paramesonephric
(mullerian) ducts.
These ducts also form the upper 2/3 of the vagina
and the fallopian tubes.
Divided into 3 segments: fundus, lower
segment and cervix.
3 layers: serosa, myometrium (smooth muscle),
and endometrium.
Gynecologic Viscera
Fallopian tubes: 10-14 cm in length,
<1 cm in diameter.
Isthmus - 1 mm in
diameter - perfect
spot for tubal
ligation.
Ampulla - 6mm in
diameter fertilization occurs
here as well as most
ectopics.
Ligamentous Support
Round Ligament:
Fibrous and muscle tissue
Anterior to the fallopian tubes
Correlate with the male gubernaculums
They extend laterally, cross the external iliac
vessels, and enter the internal inguinal ring,
and insert in the labia majora.
Sampson’s artery, a branch of the uterine
artery, runs along the length of the round
ligament.
Ligamentous Support
Broad Ligament:
Double reflection of the peritoneum, draped
over the round ligaments.
Cardinal Ligament:
Found at the base of the broad ligament.
Provides the main support for the uterus and
cervix.
It attaches to the cervix and extends laterally,
connecting to the endopelvic fascia.
Ligamentous Support
Uterosacral Ligaments:
Provide minor cervical support.
Originate from the upper posterior
cervix, travel around the rectum
bilaterally, and fan out to attach to the
1st - 5th sacral vertebrae.
Gynecologic Viscera
Ovaries:
Supported along the lateral pelvic
sidewalls by the ovarian ligaments
(attaching to the posteriolateral aspect of
the uterus), the mesovarium
(anastomotic region of the uterine and
ovarian vessels), and the infundibulopelvic ligament (“The IP”), which are
reflections of the broad ligament
attaching the ovaries to the lateral pelvis.
Ovaries
They rest in the ovarian fossa, immediately
adjacent to the iliac vessles and the
ureters.
They contain 3 distinct cell populations:
Germ cells
Stromal cells - tightly packed around
developing follicles and secrete hormones.
Epithelium
Bladder and Rectum
Don’t forget they are close by…
Bladder is anterior to the uterus.
Ureters originate in the renal calyces
and insert in to the inferior bladder at the
trigone.
Careful attention to the ureters path in the
pelvis is essential for dissection in
gynecologic surgery.
Key Points of the Ureter
In the pelvis the ureter runs medial to
and parallel with the internal iliac
artery.
Uterine artery crosses over the ureter
(water under the bridge).
The remaining 2-3cm of the ureter
passes through the cardinal ligament
into the bladder.
Rectum
Lies posterior to the uterus following
the curvature of the sacrum.
Blood Supply
Majority originates from the internal
iliac artery (aka: hypogastric artery).
Additional supply comes from the
ovarian arteries, the inferior mesenteric
artery, and the external iliac artery.
Common iliac --> external and
internal iliac
External becomes the femoral artery
Internal iliac --> anterior and posterior
divisions
Posterior division - rarely seen in pelvic
surgery, has three branches that supply the
gluteal region:
– Superior gluteal
– Iliolumbar
– Lateral sacral arteries
Anterior division:
Uterine
Vaginal
Superior, Middle, and Inferior Vesicals
Middle and Inferior Rectal
Obturator
Inferior gluteal
Internal Pudendal
Obliterated umbilical arteries
During retroperitoneal surgery the
primary branches identified are the:
Superior vesical artery
Uterine artery
Obturator artery
Ovarian arteries
Originate directly from the aorta, inferior to the
renal arteries.
Most frequently identified at the IP ligament.
Ovarian veins:
Left ovarian vein drains into the left renal vein
Right ovarian vein drains directly into the
inferior vena cava.
Lymph Drainage
Cervical Cancer:
Drains 1st to the parametrial nodes -->
obturator nodes --> pelvic nodes --> para-aortic
Uterine Cancer:
Drains 1st to the pelvic nodes or para-aortic.
Ovarian Cancer:
Can metastasize to either the pelvic or paraaortic nodes.
Pelvic Support
Pelvic diaphragm is retroperitoneal
and supports all the viscera.
Composed of the:
Levator ani group: puborectalis,
pubococcygeus, and ileococcygeus.
Coccygeous muscles
Question #1
In a CT scan of the pelvis, the uterus
is located:
A) Posterior to the bladder and rectum
B) Posterior to the bladder and anterior
to rectum
C) Anterior to the bladder and rectum
D) Anterior to the bladder and posterior
to the rectum
Answer
B) Posterior to the bladder and
anterior to the rectum.
Question #2
A 27 year-old woman is examined by her
gynecologist. Upon rectal examination, a
firm structure, directly in front of the
rectum, in the midline, is palpated through
the anterior wall of the rectum. The
structure is:
A) Bladder
B) Body of uterus
C) Cervix of uterus
D) Pubic symphysis
E) Vagina
Answer
C) Cervix of uterus
The cervix of the uterus is anterior to the
rectum
Since the cervix is the inferior part of the uterus
that is protruding into the vagina, it should feel
like a firm structure upon palpation
Although the vagina is directly anterior to the
rectum, it would not feel like a distinct and firm
structure upon palpation.