Clinical Anatomy of Bony Pelvis Flashcards
features of bony pelvis?
2 hip bones - ilium - ischium - pubis sacrum coccyx
features of the ilium?
look like elephant ears iliac crest ASIS PSIS iliac fossa
features of the ischium?
ischiopubic ramus (below the hole) ischial spine ischial tuberosity (lower posterior lump)
features of pubis?
superior pubic ramus (above the hole)
pubic tubercle (lump near the join in the middle)
pubic arch (the join)
sub-pubic angle (angle underneath join)
what are the bony features of the pelvic inlet?
sacral promontory
ilium
superior pubic ramus
pubic symphysis
bony features of pelvic outlet?
pubic symphysis ischiopubic ramus ischial tuberosities sacrotuberous ligaments coccyx
where is the pelvic cavity located?
continuous with abdominal cavity
lies between pelvic inlet and pelvic floor
where does the inguinal ligament attach between?
ASIS and pubic tubercle
what is the name of the hole between the superior pubic ramus and ischiopubic ramus?
obturator foramen
what are the main joints of the pelvis?
sacroiliac joint hip joint (synovial) pubic symphysis (secondary cartilaginous)
where is the sacrotuberous ligament?
between sacrum and ischial tuberosity
where is the sacrospinous ligament?
between sacrum and ischial spine
what are the main functions of sacrotuberous and sacrospinous ligaments?
ensure the inferior part of the sacrum is not pushed superiorly when weight is suddenly transferred vertically through the vertebral column (e.g when jumping or late pregnancy)
the presence of the sacrotuberous and sacrospinous ligaments create which 2 foraminae?
the greater and lesser sciatic foraminae
- sacrotuberous forms posterior wall
- sacrospinous splits into upper and lower holes
what passes through the obturator foramen?
obturator membrane obturator nerve and vessels pass via obturator canal
what muscle does the obturator canal pass through?
obturator internus
what vessels are at risk in a pelvic trauma and may cause a haemorrhage?
common iliac artery
internal/external iliacs and branches
common iliac vein
sacral plexus
what are the main differences between male and female pelvis?
female
- more shallow (height wise)
- wider antero-posteriorly and transversely
- more flexible ligaments
- wider sub-pubic angle
- bigger inlet/outlet
- much larger sciatic notch
features of foetal skull?
sagittal suture coronal suture lambdoid suture (between parietal and occipital bones) anterior fontanelle (large) posterior fontanelle
what is moulding in foetal skull?
movement of one bone over another to allow the foetal head to pass through the pelvis during labour
sutures and fontanelles allow this
what is the vertex in foetal skull?
area of the foetal skull
outlined by the anterior and posterior fontanelles and parietal eminences
2 diameters measured in foetal skull?
occipitofrontal (longer)
biparietal (shorter)
how does the foetus enter the pelvic cavity and why?
should enter facing either right or left
because pelvic inlet is wider transversely then AP and foetal skull is wider occipitofrontally then biparietally
what does the “station” refer to in childbirth?
the distance of the foetal head from the ischial spines
-ve number = head is superior to the spines
+ve number = head is inferior to spines
foetal head should be in what position as it descends through pelvic cavity?
rotate as it passes through
flexed with chin on chest
how should the foetal head leave the pelvic outlet?
occipitoanterior position
extension of head on neck
(at the pelvic outlet, AP diameter is wider than transverse diameter)
