Structure of Pelvic Wall Flashcards
site in pelvic region that can be used for epidural injection
sacral hiatus
Sacral Promontory (what is it)
anterior-superior margin of vertebra S1
Sacral Canal (what is it, what does it contain within it)
caudal most part of vertebral canal
contains cauda equina
Sacral hiatus (what is it)
inferior opening to the sacral canal
Medial Mass of Sacrum (what is it)
fused vertebral bodies
Lateral Mass of Sacrum (what is it)
fused transverse processes
Median Crest of Sacrum (what is it)
fused spinous processes
Anterior and Posterior Sacral Foramen ( what are they)
‘windows’ for exit of anterior and posterior rami of sacral spinal nerves
Innominate bone (what is it made up of)
3 bones fused together
ilium
ischium
pubis
acetabulum (what is it, what is it made from)
where ilium, ischium, and pubis join
cup-like depression for articulation with head of femur
before ages 15-17 what holds the innominate bone together
only cartilage (prior to fusion)
Ischial tuberosity (what is it, what attaches to it)
roughened, posterior inferior part of ischium
site of attachment for sacrotuberous ligament
Ischial Spine (what is it, what attaches to it)
pointed process from posterior border of ischium
lies between greater and lesser sciatic notches
site of attachment of sacrospinous ligament and coccyges muscle
What two parts of the ischium are key landmarks of the pelvis
ischial spine
ischial tuberosity
Ischial Ramus (what is it)
inferior border of ischium, inferior to obturator foramen
Greater Sciatic Notch (what is it, what makes up its borders)
deep indentation in posterior border of innominate bone superior to ischial spine
superior border- ilium
inferior border- ischium
Lesser Sciatic Notch (what is it)
deep indentation in posterior border of ischium inferior to ischial spine
Pubic Symphysis (what is it)
midline cartilaginous joint between right and left pubic bones
Obturator Foramen (what is it)
hole between pubis and ischium
Superior Ramus of Pubis (where is it)
superior to obturator foramen and extends into acetabulum
Inferior Ramus of Pubis (where is it)
inferior to obturator foramen and extends into ischium
Pubic Arch (what is it)
Angle between inferior rami and bodies of both pubes
Pelvic Brim (what makes it up)
lateral mass of sacrum
arcuate line of ilium
pecten pubis and pubic crest
Iliopectineal Line (what is it)
formed from pecten pubis and arcuate line
Pecten Pubis (what is it)
raised ridge along superior rams of pubis Lateral to pubic tubercle
Pubic Crest (what is it)
ridge Medial to the pubic tubercle on the body of the pubis
the superior margin of the pubic symphysis and the anterior superior iliac spine have what relation to each other
(in terms of orientation of the pelvis)
lie in same vertical plane
in a fracture of the pelvis one must assume damage to what two structures
urinary bladder
urethra
what two joints are found in the vertebral column of the pelvis
lumbrosacral
sacrococcygeal
Sacroiliac Joint (what is its purpose)
transmits weight of trunk to innominate bone (transferring weight to hear of femur in thigh)
Sacroiliac Joint (what is it made up of)
held together by strong-
interossous ligaments
anterior and posterior sacroilliac ligaments
Iliolumbar Ligament (what is it, where does it span)
strong accessory ligament from transverse process of L5 to iliac crest
Sacrotuberous Ligament (what and where is it)
broad attachment to sacrum and narrows inferiorly to attach to ischial tuberosity
posterior to the sacrospinous ligament
Sacrospinous Ligament (what and where is it)
triangular shape
attaches to lateral margin of sacrum and ischial spine
anterior to sacrotuberous ligament
What is the purpose of the sacrospinous and sacrotuberous ligaments
prevent sacrum and coccyx from rotating posteriorly due to weight of trunk (center of gravity is anterior to sacrum)
The presence of the sacrotuberous and sacrospinous ligaments give rise to what?
greater and lesser sciatic foramina
Greater Sciatic Foramen (what is it)
‘window’ through which neurovascular structures and a muscle (piriformis) pass from true pelvis into gluteal region
Lesser Sciatic Foramen (what is it)
‘window’ through which neurovascular structures and a muscle (obturator internus) pass from buttock to perineum
Obturator Membrane (where and what is it)
covers obturator foramen
serves as site of muscle attachment
False Pelvis (what is it)
located above pelvic brim
part of posterior wall of abdominal cavity
True Pelvis (contents)
lower part of GI tract urogenital organs (urinary bladder, rectum, female reproductive organs, associated glands of both sexes)
True Pelvis (boundaries)
Pelvic Inlet- superior opening
Pelvic Outlet- inferior opening
Pelvic Inlet (what is it, what are its borders)
superior opening of true pelvis
formed form pelvic brim (lateral mass of sacrum, iliopectineal line (arcuate line of ilium and pecten pubis), pubic crest)
Pelvic Outlet (what is it, what are its borders)
inferior opening of true pelvis
bordered by tip of coccyx, sacrotuberous ligament, ischial tuberosity, inferior ramus of pubis, and pubic symphysis
measurements of what are used to determine the size of birth canal
pelvic inlet
Diagonal Conjugate Diameter (what is it a measurement of, where is it taken)
anteroposterior measurement of pelvic inlet
between lower border of the pubic symphysis and the sacral promontory