The Pelvis Flashcards
1
Q
Describe the function of the pelvis
A
- support the spinal column, the weight of the upper body, and transmits this to the lower limbs
- contains and protects the reproductive organs, bladder and rectum
- attachment for muscles
- bony birth canal through which the fetus must pass
2
Q
What is the clinical application of the anatomy and physiology of the pelvis?
A
- assessing the adequacy of pelvic size
- monitoring the fetal navigation of the changing curves and diameters of the human birth canal, identifying position and descent by relevant landmarks
- recognising deviations from normal physiology and expediting appropriate care
3
Q
What is the gynaecoid pelvis?
A
- the size and shape are adequate for the fetus to traverse during birth
- it is light but strong
- it is a bony ring made up of 4 irregular bones
- > 2 Inominate bones
- > 1 sacrum
- > 1 coccyx
4
Q
Describe the innominate bone
A
- the ilium
- the ischium
- the pubis
5
Q
Describe the components of the sacrum
A
- ala
- sacral foramina
- coccyx
6
Q
Describe the pelvic joints
A
- symphysis pubis
- -> formed at the junction of the two pubic bones which are united by a pad of cartilage
- 2 sacroiliac joints
- -> these are the strongest joints in the body
- -> they join the sacrum to the ilium and thus connect the spine to the pelvis
- sacrococcygeal joint
- -> where the base of the coccyx articulates with the base of the sacrum
7
Q
What happens to the pelvic joints during pregnancy?
A
- in pregnancy the ligaments soften and allow the joints to give
- this may provide more room for the fetal head as it passes through the pelvis
- the symphysis pubis may separate slightly in later pregnancy
8
Q
Describe the pelvic ligaments
A
- each of the pelvic joints is held together by ligaments
- -> intrapubic ligaments - at symphysis pubis
- -> sacroiliac ligaments
- -> sacrococcygeal ligaments
- 2 other important ligaments
- -> sacotuberous ligaments (runs from sacrum to ischial tuberosity)
- -> sacrospinous ligaments (runs from sacrum to ischial spine)
9
Q
What are the diameters of the pelvic prim?
A
- anterior posterior 11cm
- oblique 12 cm
- transverse 13 cm
10
Q
Describe the difference between the false pelvis and the true pelvis
A
- the false pelvis is the upper part, it plays no part in labour
- the true pelvis is the lower part
- -> it consists of the brim, inlet, mid cavity and outlet
- -> it is bounded at the back by the sacrum, at the sides the ischia and front by the pubis
11
Q
Describe the pelvic cavity
A
- the pelvic cavity extends from the brim above to the outlet below, it forms a curved canal
- the anterior wall is formed by the pubic bones and symphysis pubis and its depth is 4cm
- the posterior wall is formed by the curve of the sacrum which is 12cm in length
- it is circular in shape so all its diameters are 12cm
12
Q
What are the diameters of the pelvic outlet?
A
- it is diamond shaped
- anterior posterior 13cm
- oblique 12cm
- transverse 11cm
13
Q
Describe the pelvic inclination
A
- when a woman is standing upright her pelvis is on an incline
- the axis of the pelvis canal is a line drawn half way between the anterior and posterior walls of the pelvic canal, it is known as the curve of carus
14
Q
How can a midwife help assist progress?
A
- iliac crest pressure
- pelvic rocking
- reversing the chi
15
Q
Describe the android pelvis
A
- more masculine in shape and diameters
- heart shaped brim
- feel funnel shaped cavity
- straight sacrum = contracted pelvic outlet
- narrowed sup-pubic arch <90 degrees
- prominent ischial spines
- -> hinders internal rotation of head and may result in deep transverse arrest
