Bony Pelvis in Relation to Labour & Trauma Flashcards
What are the functions of the bony pelvis?
Support of upper body
Transference of weight
Attachment for muscles
Attachment for external genitalia
Protection of pelvic organs
Passage for childbirth
The bony pelvis consists of ?
2 hip bones
Sacrum
Coccyx
Each hip bone is a fusion between?
Ilium
Ischium
Pubis
What is another name for hip bone?
Innominate bone
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Label this diagram of the ilium
Label this diagram of the ischium
Label this diagram of the pubis
What are parts of the pelvic inlet?
Sacral promontory
Ilium
Superior pubic ramus
Pubic symphysis
What are the parts of the pelvic outlet?
Pubic symphysis
Ischiopubic ramus
Ischial tuberosities
Sacrotuberous ligaments
Coccyx
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Where does the pelvic cavity lie?
Lies within bony pelvis
Continuous with abdominal cavity above
Lies between pelvic inlet and pelvic floor
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What ligament attaches between the ASIS And pubic tubercle?
Inguinal ligament
What bony landmarks are palpable on vaginal examination at approx 4 and 8 o clock position?
Ischial spines
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What are the main ligaments to know of the pelvis?
Sacrotuberous ligament
Sacrospinous ligament
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What are the functions of the pelvic ligaments?
Protect against sudden weight transfer
The presence of the sacrotuberous and sacrospinous ligaments form what foramina?
Greater and lesser sciatic foramaniae
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The ligaments of the pelvis do what in pregnancy?
Relax
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Why do we need to know about trauma to the pelvis?
Description of trauma
Knowledge of complications - pelvis is like armour and when trauma happens we are concerned about its contents
Fractures tend to be multiple or combined with joint dislocation
What is a straddle injury?
What is this?
What vascular complication can happen as a result of pelvic trauma?
Life threatening haemorrhage and / or damage to pelvic organs
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What are the differences in pelvic shape between men and women?
AP and transverse diameters of female pelvis are larger than male, both at pelvic inlet and outlet
Subpubic angle (and pubic arch) in the female is wider than male
Pelvic cavity is more shallow in female
What is moulding?
The movement of one bone over another to allow the fetal head to pass through the pelvis during labour
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What is the vertex?
The vertex is an area of the foetal skull: outlined by the anterior and posterior fontanelles and the parietal eminences
The ___ diameter is longer than the ____ diameter (i.e. the fetal head is longer than it is wide)
The occipitofrontal diameter is longer than the biparietal diameter
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At the pelvic inlet, the ___ diameter of the pelvis is wider than the ___ diameter
The transverse diameter of the pelvis is wide than the AP diameter
In the fetal skull, the ___ diameter is longer than the ___ diameter
Occipitofrontal diameter is longer than the biparietal diameter
The fetus should ideally enter the pelvic cavity facing either to the ?
Right or left (transverse) direction
The distance of the fetal head from ischial spines is referred to as?
the station
A negative station number means what?
The head is superior to ischial spines
A positive station number means what?
The head is inferior to the spines
While descending through the pelvic cavity, the fetal head should?
Rotate
Be in a flexed position, i.e. chin on chest
At the pelvic outlet, the ___ diameter is wider than the __ diameter
AP diameter is wider than transverse diameter
The baby should ideally leave the pelvic cavity in a ____ position
Occipitoanterior (OA) position
During delivery, the fetal head should be in what position?
In extension
Describe the movement of the fetal head during childbirth
Once the baby’s head has been delivered, what do we do then?
Further rotation so that shoulders and the rest of baby can be delivered
