Anatomy - Bony Pelvis Flashcards
what is the bony pelvis made of?
two hip bones
sacrum
coccyx
what does a hip bone consist of?
ilium
ischium
pubis
what forms the outline of the pelvic inlet?
sacral promontory
ilium
superior pubic ramus
what forms the outline of the pelvic outlet?
pubic symphysis ischiopubic rams ischial tuberosities sacrotuberous ligaments coccyx
where is the pelvic cavity located?
within the bony pelvis
in between the pelvic inlet and the pelvic floor
where does the inguinal ligament attach?
between the ASIS and the pubic tubercle
when are the ischial spines palpable?
on vaginal examination
what are the two main ligaments of the pelvis?
sacrospinous
sacrotuberous
where does the sacrospinous ligament attach?
between the sacrum and the ischial spine
where does the sacrotuberous ligament attach?
between the sacrum and the ischial tuberosity
what is the main function of the ligaments of the pelvis?
protect against sudden weight transfer
what happens to the ligaments of the pelvis during pregnancy?
they relax
what do the sacrospinous and sacrotuberous ligaments in the pelvis form?
the greater and lesser sciatic foramina
describe the differences between a male and female pelvis
overall a females pelvis is larger, wider and shallower than a males
what is moulding and when does this occur?
movement of bones over each other in the foetal skull to allow the head to pass through the pelvis during labour
what allows moulding of the foetal skull to occur?
the anterior and posterior fontanelles
where is the vertex located?
between the anterior and posterior fontanelles and the parietal eminences in the foetal skull
which diameter of the foetal skull is longer - occipitofrontal (back to front) or biparietal (left to right)?
occipitofrontal
what direction should the foetuses head be facing when entering the pelvic cavity and why?
either to the right or left (transverse)
the transverse diameter of the pelvis is wider than the AP diameter
what Is the station of a foetal head?
the distance of the foetal head from the ischial spines
what does it mean if the station is a negative number?
foetal head is superior to the ischial spines
what does it mean if the station is a positive number?
the foetal head is inferior to the ischial spines
what should happen to the foetal head as it passes through the pelvic cavity?
should rotate
be in a flexed position (chin to chest)
what position should the babies head be in as it exits the pelvic cavity and why?
occipitoanterior (OA) position
AP diameter is wider than transverse diameter at the pelvic outlet
what is the OA position?
the occipital bone at the back of the babies head is at the anterior surface of the mother
essentially face down and head first
what position should the babies head be in during delivery - extension or flexion?
extension
