Anatomy 1 - Clinical Anatomy of the Bony Pelvis Flashcards
Functions of bony pelvis? (5)
Supports upper body
Transfers weight from vertebral column to femurs for standing and walking
Attachment site for muscles and external genitalia
Protection of pelvic organs, vessels, nerves and lymphatics
Passage way for childbirth
What does the bony pelvis consist of?
2 hip bones
Sacrum
Coccyx
What 3 bones fuse to form each hip bone?
Ilium
Ischium
Pubis
What does the pelvic girdle consist of?
2 hip bones
Sacrum
Where do the 3 bones which make up the hip bone fuse?
Within the acetabulum
What runs between the anterior superior iliac spine and the posterior superior iliac spine?
iliac crest
What is formed at the fusion of the ischium and pubis?
Ischiopubic ramus
Name 2 features of the ischium that can be identified posteriorly?
Ischial spine
Ischial tuberosity
What is the name for the hole between the ischiopubic ramus and superior pubic ramus in a bony pelvis without ligaments attached?
Obturator foramen
What is the upper bony feature of the obturator foramen called?
Superior pubic ramus
What is the prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the pubis?
Pubic tubercle
What is the name for the lower border below the pubic symphysis?
Pubic arch
What ligament attaches between the ASIS and pubic tubercle?
inguinal ligament
What 4 bones/ bony features make up the pelvic inlet?
Sacral promontory
Ilium
Superior pubic ramus
Pubic symphysis
What 5 bones/ bony features make up the pelvic outlet?
Pubic symphysis Ischiopubic ramus Ischial tuberosities Sacrotuberous ligaments Coccyx
What is the name for everything between the pelvic inlet and pelvic floor?
What is the name for everything starting at the pelvic brim?
True/ lesser pelvis
False/ greater pelvis
What does the pelvic cavity lie between?
Pelvic inlet and pelvic floor
What does the pelvic cavity contain?
Pelvic organs and supporting tissues
What part of the bony pelvis is palpable on vaginal examination?
What clock positions are these present at?
Ischial spines
Approximately 4 and 8 o’clock
Joints of the pelvis?
Sacroiliac joints
Hip joints
Pubic symphysis
What type of joints are the sacroiliac joints?
Synovial more anteriorly and fibrous more posteriorly (very rough division)
What ligaments of the pelvis run between the sacrum and ischial spine?
Sacrospinous ligament
What ligaments of the pelvis run between the sacrum and ischial tuberosity?
Sacrotuberous ligament
What is the purpose of the 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 during late pregnancy
What 2 foramina are formed from the sacrospinous and sacrotuberous ligaments?
Greater and lesser sciatic foramen
What is the name of the hole between the ischiopubic ramus and the superior pubic ramus?
Obturator foramen
What is the name of the gap in the obturator membrane on the obturator foramen?
Obturator canal
What passes through the obturator canal?
Obturator nerve and vessels
Is a fracture of the pelvis likely to be in isolation or multiple?
Multiple (or combined with joint dislocation)
Which 4 parts of the bony pelvis are most likely to be fractured?
Pubic rami
Ala of the ilium
Acetabulum
Sacroiliac joints
What is the biggest concern regarding trauma to the bony pelvis?
Life threatening haemorrhage and/ or damage to pelvic organs
Is the diameter of a male or female pelvis larger?
Female
Which sex has a wider subpubic angle?
Female
Which sex has a more shallow pelvic cavity?
Female
Which sex has thinner pelvic bones?
Feamle
Shape of pelvic inlet in males?
Heart shaped
Shape of pelvic inlet in females?
Round
Is the sacrum and coccyx more curved inwards in males or females?
Males
At what age approximately does the anterior fontanelle close?
About 18 months
Name of the main fontanelles?
Anterior fontanelle
Posterior fontanelle
Lateral fontanelle (sphenoidal and mastoid fontanelles) X2
Name of the suture between the parietal and occipital bones?
Lambdoid suture
What is moulding?
The movement of one bone over another to allow the foetal head to pass through the pelvis during labour
What is the name of the area of the foetal skull outlined by the anterior and posterior fontanelles and the parietal eminences?
Vertex
Is the occipitofrontal or biparietal diameter longer in the foetal skull?
Occipitofrontal
In what direction should the foetus enter the pelvic cavity?
Why?
Either facing right or left
In the foetal skull, the occipitofrontal diameter is longer than the biparietal diameter and at the pelvic inlet, the transverse diameter of the pelvis is wider than the AP diameter
In which position should the foetal head be as it descends through the pelvic cavity?
Flexed i.e. chin on chest
Rotated
In what direction should the baby leave the pelvic cavity?
Why?
In an occipitoanterior position (babies head facing bed)
At the pelvic outlet, the AP diameter is wider than the transverse diameter
During delivery, what position should the foetal head be in?
Extension
Once the baby’s head has delivered, what position should the baby’s body be delivered?
Rotated - one shoulder can be pulled out the vagina at a time
What does the pudendal nerve supply?
Perineum
When would you do a pudendal nerve block?
If doing a forceps delivery
How do you do a pudendal nerve block?
Approach via vagina
Feel for ischial spine
Aspirate to ensure not in artery
Inject LA
