Uterus Flashcards
What is the uterus?
Thick walled, pear shaped muscular organ of gestation located in lesser pelvis
What general structures make up the uterus?
Body and Cervix
What structures make up the body of the uterus?
uterine cavity, uterine horns, fundus, isthmus
What is the body of the uterus?
Freely movable superior 2/3 of uterus
What are the surfaces of the body (uterus)?
Vesical surface- adjacent to urinary bladder
Intestinal surface- adjacent to rectum
What is the uterine cavity?
narrow, slit like lumen about 6cm in length
What are the uterine horns?
superolateral origins of uterine tubes
What is the fundus?
rounded part of body superior to the uterine horns
What is the isthmus?
short, constricted region just superior to cervix
What is the cervix?
Cylindrical inferior portion of uterus protruding into vagina
What is the cervix divided into?
Supravaginal and Vaginal part
Where is the Supravaginal part of the cervix?
between the isthmus and vagina
What is the supravaginal part of the cervix separated from the rectum by?
posteriorly by rectouterine pouch
Where does the vaginal part of the cervix protrude and what is it surrounded by?
Protrudes into vagina and surrounded by vaginal fornix
What structures are located within the vaginal part of the cervix?
internal os, external os and cervical canal
what is the internal os?
internal opening to uterine cavity of isthmus
What is the external os?
external opening to the vagina
What is the cervical canal?
spans cervix from internal os to external os
How is the adult uterus oriented, relative to the vagina?
anteverted
How is the adult uterus oriented, relative to the cervix?
anteflexed
What does the uterine body normally lie on/is supported by?
urinary bladder
T/F: The uterine position doesn’t change as urinary bladder and/or rectum fill?
False, moves for both
Histological layers of the uterus?
perimetrium, myometrium and endometrium
What is the perimetrium layer of the uterus?
Thin outer serosal covering
What is the myometrium?
Thickest layer comprised of irregularly arranged smooth muscle
-Changes drastically during pregnancy (but not during menstrual cycle)
What is the endometrium?
thins mucosal lining; site of blastocyst implantation
-Changes dramatically during each menstrual cycle
What are the ligaments of the uterus and ovaries?
Broad lig. of the uterus Round lig. of uterus Ovarian lig. Suspensory lig. of ovary Cardinal lig. Uterosacral lig. Pubocervical lig.
What is the Broad lig. of the uterus?
Double layer of peritineum that helps hold uterus in place
- anterior lamina borders vesicouterine pouch
- posterior lamina borders rectouterine pouch
Are the anterior and posterior lamina of the broad lig. of the uterus continuous at some point?
Yes, continuous with each other over free edge of uterine tubes
Where does the broad lig. of the uterus extend? and what does it form?
extends form lateral wall of uterus to lateral walls and floor of pelvis (this isn’t misspelled, so leave me alone)
- Froms a transverse septum in pelvic cavity
What are the portion of the Broad lig. of the uterus?
Mesometrium, mesovarium and mesosalpinx
What is the mesometrium?
large section of the broad l. lateral to uterus
What is the mesovarium?
Extension of broad l. forming mesentery of overy
what is the mesosalpinx?
Extension of broad l. forming mesentery of uterine tube
What is the round lig.?
Attaches anteroinferiorly to uterotubal junction (uterine origin is between layers of Broad l.)
-Passes through inguinal canal to insert into labium majus
What structure is the adult remnant of the inferior part of the gubernaculum? (in women, duh)
Round lig. of the uterus
What is the ovarian lig.?
Spans from uterus to ovary
- attaches posteroinferiorly to uterotubal junction
- uterine origin is between layers of broad l.
What is the adult remnant of the superior part of the gubernaculum? (once again in women…..)
Ovarian lig.
What is the suspensory l. of the ovary?
superior extension of broad lig. toward abdomen
surrounds neurovascular elements supplying ovary
What is the cardinal lig.?
Extend from cervix and lateral fornix of vagina to lateral walls of pelvis
-Located along inferior margins of broad lig.
What is the uterosacral lig.?
Pass superoposteriorly from sides of cervix to middle of sacrum
-Tension here is possibly responsible for anteversion of uterus
Is the uterosacral lig. palpable via digital rectal exam?
yes
what is the pubocervical lig.?
Extends from posterior surface of pubic bones to cervix
How is uterine position maintained?
by the ligaments and support from pelvic diaphragm
Uterine prolapse is inhibited by what?
position of uterus overlying urinary bladder
When would prolapse be more likely?
if uterus were in same vertical plane as vagina
What does prolapse mean? (for those of us that don’t spend there life in a medical dictionary)
to fall out of place
What is a caudal epidural block?
Anesthetic administered in advance of actual delivery
How is a caudal epidural block administered?
via in-dwelling catheter in sacral canal
-enables additional anesthetic to be administered as necessary
Which nerve roots are anesthetized via a caudal epidural block?
nerve roost of S2-S4
-anesthetizes fibers in Pudendal n. plus uterus and upper vagina
Are women aware of uterine contractions with a caudal epidural block?
yes, but doesn’t experience most of the pain
Are spinal headaches associated with caudal epidural blocks?
No, because vertebral epidural space is not continuous with cranial epidural space
What is a pudendal n. block?
Anesthetic injected near pudendal n. where it passes over ischial spine
- effects S2-S4 dermatomes (majority of perineum and lower vagina)
- additional anesthetic may be re-administered if necessary
Does a pudendal n. block anesthetize sensation of uterine contractions from the uterus and upper vagina?
No
What is a hysterectomy?
Excision of the uterus
-may be performed through abdominal wall or vagina
Relationships between uterus anteriorly?
Associated with vesicouterine pouch and superior surface of urinary bladder
-supravaginal part of cervix separated from urinary bladder by loos CT
Relationships between uterus posteriorly?
associated with rectouterine pouch and anterior surface of rectum
-loops of ilium may fill rectouterine pouch
Relationships between uterus laterally?
Anchored to lateral pelvic wall by broad lig. and cardinal lig.
-Ureters pass slightly superior to the vaginal fornix
What is the arterial supply to the uterus?
Uterine a. (branch from internal iliac a.)
-Ovarian a. and vaginal a. anastomose with uterine a.
What is the venous drainage of the uterus?
uterine venous plexus drains to internal iliac v.
What is the lymphatic drainage of uterus?
- Fundus drains primarily to lumbar plexus
- Body drains through broad lig. to external iliac nodes
- Cervix drains to either internal iliac or sacral lymph nodes
What is the innervation to the uterus?
Uterovaginal plexus that travels with uterine a. at base of broad lig.
-extension of inferior hypogastric plexus
What are the sympathetics and parasympathetics supplied by?
sym- lumbar splanchnic n.
para- pelvic splanchnic n. (S2-S4)
What do the visceral afferents follow?
- afferents form body/fundus –> follow sympathetics (lumbar splanchnic n.)
- afferents from cervix follow parasympathetics (pelvic splanchnic n.)
General anesthesia
Not commonly used except in emergency procedures
- renders woman unconscious and unaware of labor and delivery
- childbirth occurs passively under control of maternal hormones
- clinicians monitor and regulate maternal respiration and maternal respiration and maternal/fetal cardiac function
Regional anesthesia
Allows woman to participate in child birth by assisting contractions
-Reduces exposure to pain of labor and child birth
What is a spinal block?
anesthetic agent introduced into subarachnoid space at L3/L4
- anesthetizes everything inferior to waist including perineum, pelvic floor, birth canal, uterine pain sensations, motor/sensory of lower limbs
- difficult of impossible to re-administer if labor is long
Is electronic monitoring of contractions necessary for spinal blocks?
yes, required
What is an issue with spinal blocks?
The anesthetic stays in lower spinal subarachnoid space when sitting/upright, but when lying flat, the anesthetic circulates to cranial cavity commonly resulting in severe headaches
