1.06 Dystocia - Passageway Flashcards
T/F: A Cephalopelvic disproportion usually warrants a CS delivery
T
This bony landmark corresponds to the midplane, which is the narrowest plane in the bony pelvis
Ischial spine
Ischial tuberosity is used to assess what?
Outlet
The (true/false) pelvis is the area above the linea terminalis
The (true/false) pelvis is the area below the linea terminalis
What are the 4 divisions of the true pelvis?
FALSE- above
TRUE - below
4 divisions: pelvic inlet, midplane, pelvic outlet (obstetrical outlet), pelvic plane of the greatest dimension
where is the pelvic inlet?
It spans from the superior border of the symphysis pubis to the level of sacral promontory
What is the obstetrical outlet?
The distance between the two ischial tuberosities
An outright cesarean section is only performed for certain fetal sizes or when the estimated fetal weight is:
more than 4,500 g
T/F: Radiologic pelvimetry is often done
F
-not often done, unless the px wants to undergo trial of labor but the fetus is in breech position
What position is desired for a fetus to be delivered vaginally?
Occiput anterior
Why is occiput posterior (6 o clock position) not ideal?
Since the frontum will hit the maternal pubic bone and prevent flexion and descent, unless it is much smaller size
T/F: An epidural anesthesia is ideally needed in clinical pelvimetry
T
How to compute for the obstetrical conjugate?
What is the adequate pelvic inlet?
How to compute for the true conjugate?
Obstetrical conjugate = Diagonal conjugate - 1.5 to 2cm
> 11.5cm
True conjugate = Diagonal conjugate - 1-1.5cm
T/F: The retropubic angle can be assessed if the head is engaged
F- done if head is NOT yet engaged
Shapes of retropubic angle
What is the preferred shape?
Shapes: round, angulated, narrow, wide
Preferred: wide
What is the Mueller-Hillis Method?
an old method when the OB attempts to reposition the head of the fetus during IE, guiding it into the pelvic inlet
Usual dimension of the midplane
How do you crude estimate the midplane?
Indication of <10cm midplane distance
10-10.5 cm
-Palpate the prominence of the ischial spines and measure the distance between them
If <10cm, it could be abnormal/contracted
What is head engagement?
When the biparietal diameter of the fetus has reached the pelvic inlet and/or surpassed the linea terminals -> now in the true pelvis
T/F: Engagement means the head is at station 0
F
In protracted labor, the head might be engaged but can have caput -> the station can be lower than station 0
In gynecoid:
The ischial spines are (prominent/not prominent)
Sacral promontory is (reached/not reached)
Inlet is (adequate/inadequate)
In gynecoid: (round shape)
The ischial spines are NOT PROMINENT
Sacral promontory is NOT REACHED (>11.5 CM)
Inlet is ADEQUATE
In Android:
The ischial spines are (prominent/not prominent)
Sacral promontory is (reached/not reached)
Inlet is (adequate/inadequate)
In android (heart shaped):
The ischial spines are PROMINENT
Sacral promontory is REACHED
Inlet is INADEQUATE (ALL MEASUREMENTS ARE INADEQUATE)
In Anthropoid:
The ischial spines are (prominent/not prominent)
Sacral promontory is (reached/not reached)
Inlet is (adequate/inadequate)
In Anthropoid (Narrow oval shape)
The ischial spines are PROMINENT
Sacral promontory is NOT REACHED
Inlet is ADEQUATE
in Platypelloid:
The ischial spines are (prominent/not prominent)
Sacral promontory is (reached/not reached)
IN PLATYPELLOID (FLAT OVAL SHAPE):
The ischial spines are NOT PROMINENT (Blunt)
Sacral promontory is REACHED
What pelvic types have narrow bispinous diameter?
What pelvic types have wide bispinous diameter?
Narrow (<10cm): Android, anthropoid
Wide (>10cm): Platypelloid
This way of assessing the midplane measures the hollow area in the posterior border of the ischial spine
Sacrosciatic Notch
