Chapter 39: Normal Pelvic A&P Flashcards
The bony pelvis consists of what four bones?
- 2 innominate bones
- sacrum
- coccyx
Each innominate bone is made of:
- ilium
- ischium
- pubis
Where do the innominate bones fuse?
join posteriorly at the sacrum and coccyx and fuse anteriorly at the pubic symphisis
How do pelvic muscles typically appear?
hypoechoic with hyperechoic striations when viewed in long axis
Where are the psoas major muscles
originate at the transverse process of the lumbar vertebrae and descend inferiorly through the false pelvis on the lateral sidewalls
What muscles do the psoas major muscles join with in the false pelvis?
ilacus muscles, forming the iliopsoas muscles
Describe piriformis muscles and where they are
flat, triangular muscles that arise from the anterior sacrum and pass through the greater sciatic notch on the posterior aspect of the innominate bone to insert into the superior aspect of the greater trochanter of the femur
Describe obturator internus muscles and where they are
triangular sheets of muscle that arise from the anterolateral pelvis wall and surround the obturator foramen
What muscles form the pelvic diaphragm?
levator ani and coccygeus muscles
What is the levator ani?
a group of 3 muscles that extend across the pelvic floor like a hammock:
- pubococcygeus muscles
- iliococcygeus muscles
- puborectalis muscles
Where are the coccygeus muscles found?
posterior pelvic floor (support coccyx)
T/F: levator ani plays an important role in continence?
T
What helps you ID ureters?
ureteral jets in the posteroinferior bladder
The uterine cervix protrudes into the upper portion of the vaginal canal, forming four archlike recesses called:
fornices
The uterus has what parts?
- fundus
- body (corpus)
- cervix
What is the widest, most superior portion of the uterus?
fundus
What are found at the lateral corners of the uterus?
cornua
What is the cervix?
lower cylindrical portion of the uterus that projects into the vaginal canal
What are the 3 layers of the uterine wall?
- serosa/perimetrium
- myometrium
- endometrium
What are the two layers of the endometrium?
- superficial functional layer (zona functionalis)
2. deep basal layer (zona basalis)
Describe the basal layer of the endometrium?
thin layer of the blindends of the endometrial glands that regenerates new endometrium after menses
The uterus is supported in its midline positioned by what paired ligaments?
- broad ligaments
- cardinal ligaments
- uterosacral ligaments
- round ligaments
Describe the broad ligaments
a double-fold of peritoneum that drape over the fallopian tubes, uterus, and ovaries and contain the uterine blood vessels and nerves (sheet-like)
What are the 3 broad ligaments?
- mesovarium
- mesosalpinx
- mesometrium
Describe the round ligaments
fibrous cords that occur in front of and below the fallopian tubes between the layers of broad ligament
Describe the cardinal ligaments
continuation of the broad ligaments that extend across the pelvic floor laterally and firmly support the cervix
Describe the uterosacral ligaments
originate at the lateral uterine isthmus and extend downward along the sides of the rectum to the sacrum, firmly supports cervix
The average uterine position is
anteverted and/or anteflexed
What is anteverted?
when cervical canal forms a 90 degree or less angle with the vaginal canal
What is retroverted?
cervical canal forms an angle less than 90 degrees with the vaginal canal
Where are the fallopian tubes?
lie superior to the utero-ovarian ligaments, round ligaments, and tuboovarian blood vessels…contained in the broad ligaments
List the 4 portions of the fallopian tubes and where they are:
- infundibulum: lateral
- ampulla: middle
- isthmus : medial
- interstitial: passes through uterine cornua
How long are ovaries on average?
3 cm long
Where do ovaries usually lie?
posterior to the uterus at the level of the cornua
What is the primary blood supply to the ovaries?
from the ovarian arteries, which anastamose with the uterine artery, providing additional blood flow
What do the ovarian arteries arise from?
lateral aspect of the abdominal aorta
What do ovaries produce?
- ovum
- estrogen (secreted by follicles)
- progesterone (secreted by corpus luteum)
How are ovaries supported?
medially by ovarian ligaments, and laterally by suspensory (infundibulopelvic) ligaments
Internal iliac AKA
hypogastric arteries
What do the internal iliac arteries perfuse to supply blood to?
urinary bladder, uterus, vagina, rectum
Where does the left ovarian vein drain into?
left renal vein
Where does the right ovarian vein drain into?
IVC
Describe uterine artery
tortuous and spirals up the sides of the uterus within the broad ligament to the cornua, where it courses laterally to anastamose with ovarian artery
Describe arcuate arteries:
arch like vessels encircling uterus…sonographically anechoic tubular structures in the outer 3rd of myometrium
Where are radial arteries
extend through myometrium to the base of endometrium
Describe spiral arteries
lengthen during the regeneration of the endometrium after menses to traverse the endometrium and supply the zona functionalis
When is blood from the spiral arteries shed?
during menses
What is polymenorrhea?
when cycle occurs at intervals of less than 21 days
What is oligomenorrhea?
when cycles is prolonged more than 35 days
When does ovulation occur (daywise)
day 14
How many oocytes at time of birth?
200,000
What does the hypothalamus release at puberty?
gonadotropin-releasing hormones
What do gonadotropin-releasing hormones do?
stimulate anterior pituitary gland to secrete FSH and LH
The secretion of FSH by the anterior pituitary causes what?
the ovarian follicles to develop during the first half of the menstrual cycle (begins first day of bleeding through ovulation on day 14)
How large is a graffian follicle right before ovulation?
2-2.5 cm
As estrogen leves in the blood rise with follicle development:
the pituitary gland is inhibited from further production of FSH and begins secreting LH
When does LH surge?
24-36 hours before ovulation
When does LH level usually reach its peak?
10-12 hours before ovulation
What triggers ovulation on day 14?
LH surge with smaller FSH surge
After ovulation, what phase does the ovary enter?
luteal stage, about 14 days in length
T/F: does the luteal phase ever vary in length?
no
What happens in the luteal phase?
cells in the lining of the ruptured ovarian follicle begin to multiply and create corpus luteum …corpus luteum immediately begins secreting progesterone
When does corpus luteum degenerate, causing progesterone levels to decline?
9-11 days after ovulation
What occurs as progesterone levels decline?
menstruation
If pregnancy occurs, how long does corpus luteum persist?
3 months
What are the three phases of endometrial cycle?
- menstrual phase (1-5)
- proliferative phase (6-14)
- secretory phase (15-28)
What is menorrhagia?
abnormally heavy or long periods, associated with fibroids or hormonal imbalances
What is oligomenorrhea?
abnormally short or light periods; often associated with PCOS..but also caused by stress, eating disorders, poor nutrition, chronic illnesses, tumors secreting estrogen
What is dysmenorrhea?
painful period, often associated with endometriosis
T/F: It’s normal to see small amount of free fluid in the posterior cul-de-sac?
True
When does the greatest quantity of fluid in the post. culdesac form?
immediately following ovulation when follicle ruptures
Hemorrhage or infection in the free fluid in the posterior culdesac may be related to what?
ruptured cyst, ascites, ruptured corpus luteum cyst, ectopic pregnancy, pelvic inflammatory disease
