The Maternal Pelvis Flashcards
the four bones of the pelvis:
2 x innominate bones
the sacrum
the coccyx
the three bones that make up innominate bones:
the ilium
the ischium
the pubis
the four pelvic joints
symphysis pubis joint
2 x sacroiliac joints
sacrococcygeal joint
the sacrum forms which wall of the pelvic cavity?
the posterior
is wedged between the innominate bones
the sacrum consists of how many fused vertebrate?
five
the coccyx (vestigial tail) consists of how many fused vertebrate?
four
pelvic joints are held together by…
ligaments
these are designed not to allow movement
the ligaments connecting the bones of the pelvis with each other can be divided into four groups.
what are those connecting the sacrum and ilium called?
the sacroiliac ligaments
the ligaments connecting the bones of the pelvis with each other can be divided into four groups.
what are those connecting the sacrum and ischium called?
sacrospinous ligaments
the ligaments connecting the bones of the pelvis with each other can be divided into four groups.
what are those connecting the sacrum and the coccyx called?
the sacrococcygeal ligaments
the ligaments connecting the bones of the pelvis with each other can be divided into four groups.
what are those connecting the two pubic bones called?
the inter-pubic ligaments
effect of the hormone relaxin during pregnancy:
gradually loosens pelvic ligaments allowing slight pelvic movement and more room for fetal head
the true pelvis is divided into three sections:
the pelvic brim
pelvic cavity
pelvic outlet
the sacrum is located between which bones?
innominate bones
the coccyx is also known as the what?
the tailbone
the brim of the pelvis is what shape?
heart shaped (round except where the sacral promontory projects into it)
the pelvic cavity extends from ? to the ?
brim to the outlet
the pelvic cavity is circular meaning…
all diameters are the same
the pelvic outlet is what shape?
diamond shaped
the greatest diameter on the pelvic outlet is found:
anteroposterior
the distance between the sacral promontory and iliopectinal emineence is known as:
the sacrotyloid diameter
what are the four types of pelvis?
gynaecoid
android
anthropoid
platypelliod
how common is a gynaecoid pelvis?
50%
rounded, straight sidewalls, sub-pubic angle 90degrees
how common is an android pelvis?
20%
heart shaped, convergent sidewalls, sub-pubic angle less than 90degrees
how common is an anthropoid pelvis?
24% - most common is non-white populations
oval shaped, divergent sidewalls, sub-pubic angle more than 90degrees
how common is a platypelloid pelvis?
6%
kidney shaped, divergent sidewalls, sub-pubic angle more than 90degrees
in each of the planes of the pelvis, there are three diameters:
the anteroposterior
the oblique
the transverse
what is the length for the anteroposterior diameter in the brim?
11cm
what is the length for the oblique diameter in the brim?
12cm
what is the length for the transverse diameter in the brim? (the greatest diameter)
13cm
the three diameters in the pelvic cavity are considered to be the exact same length:
12cms
what is the length for the anteroposterior diameter in the outlet?
13cms
what is the length for the oblique diameter in the outlet?
12cms
what is the length for the transverse diameter in the outlet?
11cms
