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123 terms

OB/GYN Anatomy

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Mound of adipose tissue, skin, and hair that cushions the pubic symphysis?
Mons Pubis (mons veneris)
Amt of fat in mons pubis does what during puberty and menopause?
Increases in puberty

Decreases in menopause
This is a terminus of the round ligament of the uterus and extends interiorly and posteriorly?
Labia majora
This is a scrotom homolog?
Labia majora
Which contains sudoriferous and sebaceous glands, labia majora or labia minora?
Labia majora
This contains only sebaceous glands, is hairless and folds medial to the labia major?
Labia minora
This is a penile shaft skin homolog?
Labia minora
Where does the labia minora merge anteriorly?
Clitoris
Covering of the clitoris?
Prepuce (clitoral hood)
This is a small, cylindrical mass of erectile tissue and nerves?
Clitoris
Exposed portion of the clitoris?
Glans
This is a glans penis homolog?
Clitoris
Where is the vestibule located?
Between the labia minora
What does the vestibule contain?
External urethral orifice
Vaginal orifice
Ducts of several glands
Where is the external urethral orifice located?
Located anterior to the vaginal orifice and posterior to the clitoris
Membranous urethra homolog?
Vestibule
What consists of 2 elongated masses of erectile tissue and is deep to the labia on both sides of the vaginal orifice?
Bulb of the vestibule
Corpus Spongiosum homolog
Bulb of the vestibule
Which glands produce a small amount of mucus during sexual arousal and provide lubrication?
Greater vestibular (Bartholin) glands
(4 and 7 o'clock)
Bulbourethral gland homolog?
Greater vestibular (Bartholin) glands
Which glands are located on both sides of the vaginal orifice?
Greater vestibular (Bartholin) glands
Which glands secrete mucus into ducts that open into the urethral orifice?
Paraurethral (Skene's) glands
Which glands are located on either side of the urethral orifice?
Paraurethral (Skene's) glands
Prostate homolog?
Paraurethral (Skene's) glands
A diamond-shaped area medial to the thighs and buttocks in males and females?
Perineum
What area contains the external genitalia and anus?
Perineum
What is the perineum bound by anteriorly?
Pubic symphysis
What is the perineum bound by laterally?
Ischial tuberosities
What is the perineum bound by posterolaterally?
Sacrotuberous ligaments
What is the perineum bound by posteriorly?
Coccyx
Name the 2 triangular areas contained in the perineum
Urogenital (external genitalia and urethral orifice) and anal (anus)
This supports the abdominal and pelvic organs, composed of levator ani and coccyges, and is important in fecal continence?
Pelvic diaphragm
What muscles compose the Levator Ani muscle group?
Puborectalis
Pubococcygeus
Iliococcygeus
T/F. The Levator Ani muscle is tonically contracted most of the time to provide fecal/urinary continence.
True
What is the urogenital diaphragm?
Fibromuscular sheet that stretches across the pubic arch
Purpose of urogenital diaphragm
Provides framework for attachment of erectile body of clitoris

Major source of vesicourethral control
This is the shape and size of an inverted pear?
Uterus
What does the uterus consist of?
Fundus
Body
Isthmus
What layer of muscle forms the Pouch of douglas and vesicouterine pouch?
Perimetrium
What is the lowest point in the abdominal cavity for fluid accumulation?
Rectouterine pouch (Pouch of Douglas)
What commonly causes excess fluid in the pouch of douglas?
Ruptured ovarian cyst
local or distant malignancy
What connects the two superficial transverse perineal muscles and is a common area for dissection to loosen up the muscles in that area?
Perineal body
Where is the perineal body located?
Center of the bases of the urogenital and anal triangles
T/F. There is no perimetrium or peritoneal separating the bladder and the cervix.
True
What area contains the thinnest part of the myometrium?
Cervix
What muscle contracts as a result of oxytocin release during labor and delivery?
Myometrium of the uterus
The myometrium contracts when what hormone is secreted during labor and delivery?
Oxytocin
How many layers compose the myometrium?
3
Which layer of the myometrium is circular?
2
Which layer of the myometrium is thickest?
Circular (middle)
What layer of the uterus is composed of simple columnar epithelium?
Endometrium
Is the endometrium ciliated and secretory?
Yes
Which layer of the uterus is most vascularized?
Endometrium
Where does the cervical canal open into the uterine cavity?
Internal os
Where does the cervical canal open into the vagina?
External os
What structure elongates during pregnancy (after the 28th week) and becomes the lower uterine segment?
Uterine isthmus
What are the main cell types of the cervix?
Squamous epi cells and columnar epi cells
Where are squamous epi cells located in the cervix?
Ectocervix (exocervix)
Where are the columnar epi cells located in the cervix?
Endocervix (cervical canal)
Portio
portion of the cervix extending into the vagina. Includes parts of the endocervix and exocervix
Fornix
Recessed vagina that borders the lateral cervix
Where does 95% of the cervical neoplasia occur?
Transformation zone
Ectropion
Columnar cells are visible on the ectocervix
When does ectropion most commonly occur?
near menarche, during pregnancy, or when using oral contraceptives
What symptoms will the patient experience when ectropion occurs?
More vaginal secretions or postcoital spotting
Which ligaments help maintain anteversion?
Round ligaments
When do gonads begin to form during gestation?
4 weeks
When do primordial germ cells in the ovary complete first meiotic division during gestation?
20 weeks
When does the undiff embryo begin to respond to gene effects of Y chromosomes?
8-9 weeks
What is the earliest that you can determine if the embryo is going to be a female or male?
8-9 weeks (appearance or non-appearance of Sertoli cells coming from the Y chromosomes)
Which of genital ducts is female, (Paramesonephric duct or Mesonephric Ducts)
Paramesonephric (Muellerian) Ducts
Which of the genital ducts is male, (Paramesonephric duct or Mesonephric Ducts)?
Mesonephric (Wolffian) ducts
What causes the phenotypic appearance in males?
Hormones produced by the fetal testes
What causes regression of the Muellerian ducts?
Mullerian Duct Inhibitory Substance (MIS) secreted by the Sertoli cells whose proliferation are generated by the Y chromosome
What is produced by the Leydig cells?
Testosterone
What is normal pH for the vagina?
3.8 to 4.5 (acidic)
How much cervical mucus does the average woman produce per day?
20 - 60 ml
How does the cervical mucus become more sperm friendly?
Becomes less viscous and more alkaline
How long are the fallopian tubes usually?
4 inches or 10 cm long
Function of the fallopian tubes
Transport the 2ndary oocytes, ovum, zygote, and sperm
Where are the fallopian tubes located?
Between the folds of the broad ligaments
What part of the fallopian tube opens to the pelvic cavity and has fimbriae on the lateral portion?
Infundibulum
What produces local currents that draw the ovulated 2ndary oocyte into the fallopian tube?
Infundibulum
T/F. The Infundibulum is attached to the contralateral ovary.
False (ipsilateral)
What is the longest part of the fallopian tube?
Ampulla
What part of the fallopian tube is connected to the anteriolateral wall of the uterus?
Isthmus
What are the 3 parts of the fallopian tube?
Infundibulum
Ampulla
Isthmus
Which layer of the fallopian tube is composed of ciliated epithelium containing secretory (peg) cells with microvilli?
Mucosa
What is the function of the secretory (peg) cells in the mucosa of the fallopian tube?
Secrete fluid containing nutrients for the oocyte (fertilized ovum and sperm)
What kind of motion does the muscularis layer of the fallopian tube perform to move the oocyte to the uterine cavity?
Peristalsis
What are the 4 major pelvic ligaments?
Cardinal
Round
Broad
Uterosacral
Which pelvic ligaments anchor the cervix and vagina to the pelvic wall and provides most of the passive support of the uterus (with the bladder)?
Cardinal
Which pelvic ligaments divide pelvis into anterior and posterior compartments?
Broad
Which pelvic ligament anchors the uterus to the pelvic wall?
Broad
Which pelvic ligament actually envelopes the round ligaments?
Broad
What is the portion of the broad ligament that contains the fallopian tube called?
Mesosalpinx
Which pelvic ligaments anchor the uterus to the sacrum?
Uterosacral
Bregma
Anterior fontanelle with 3 suture lines attached (anterior, posterior, and transverse)
What is the favorable presenting diameter of the average full term infant?
Suboccipitobregmatic (vertex, OA, flexed)
9.5cm
Name the 4 basic bony pelvic shapes
Anthropoid
Android
Gynecoid
Platypelloid
Which of the basic bony pelvic shapes are most favorable for vaginal delivery?
Anthropoid -20%
Gynecoid - 50%
What are the pelvic planes?
Pelvic Inlet

Plane of Greatest Diameter

Plane of Least Diameter

Pelvic Outlet
Pelvic inlet?
Opening into the true pelvis that contains the bladder, uterus; Path of the birth canal from sacral promontory to pubic symphisis.
How does the fetal head enter the pelvic inlet?
Enters in transverse position
What are the pelvic inlet boundaries?
Superior border of pubis
Linea terminalis (iliopectineal line)
Sacral promontory
What are the boundaries for the plane of greater diameter?
Posterior pubis at maximum convexity
Superior border of obturator formina
2nd/3rd sacral vertebral junction
What is important about the plane of least diameter?
Clinically most important

Frequent site of arrests
What is the boundaries for the plane of least diameter?
Lower posterior pubic edge anteriorly

Ischial spines and sacrospinous ligaments laterally

Sacrum posteriorly
What are the boundaries of the pelvic outlet?
Sacrotuberous ligaments and sacrococcygeal joint posteriorly

Inferior margins of pubic rami anteriorly

Ischial tuberosities laterally
what are the 3 key diameters to assess for fetal descent during labor?
Inlet
Midplane
Outlet
What are the 3 types of measurements for the pelvic inlet?
True conjugate
Obstetric conjugate
Diagnonal conjugate
What measurement of the pelvic inlet is made by measuring the length of the finger that can go into the vaginal cavity? (From sacral promontory to just outside of the vagina.)
Diagnonal conjugate
How do you get the obstetric conjugate?
Subtract 1.5 cm to 2 cm from Diagonal conjugate. (Estimating 1.5 to 2 cm of bone and soft tissue)
Fetal head engagement
Fetal biparietal diameter passes through pelvic inlet and seen in obstetric conjugate
Pelvic outlet
Distance between the maternal ischial tuberosities (Width/diameter of birth canal)
Station
Description of where the bony presenting part is in relationship to the ischial spines
What station is the bony presenting part when the head is engaged?
0 station
Asynclitic
Head engages crooked or cock-eyed instead of parallel to pelvic plane
Synclitic
Head engages parallel to the pelvic plane
What station is the bony presenting part when it is 2 cm before reaching the ischial spine?
-2 station
How can an asynclitic type of fetal head engagement help in the birthing process in some cases?
When it enters the pelvis, the asynclitic diameter is actually shorter than the biparietal diameter.
What are the estimates of the midplane?
Pelvic Side Walls
- Convergent
- Parallel (Usual and desired)

Bispinous diameter
(distance between ischial spines)
- Prominent
- Average

Sacrospinous ligament
- Usually 3 fingers between ischial spine & midline sacrum
What are the estimates of the pelvic outlet?
Posterior sagittal - >8cm

Infrapubic angle - >90 degrees

Bituberous diameter - >8.5cm