Aug27 M1-Pelvis_Anatomy_lecture_1 Flashcards
3 bones of the pelvic girdle
- hip bone
- sacrum
- coccyx
3 bones of the hip bone
- ilium (to half of greater sciatic notch)
- ischium (bottom back)
- pubis (bottom front)
baby pelvis vs adult pelvis
ilium, ischium and pubis separated bc still growing. (adult fused)
landmarks of ilium
- ala of the ilium (iliac wing (ala))
- iliac crest (top near sacrum)
- greater sciatic notch
- ASIS
- body of the ilium (near acetabulum, hip artic.)
- gluteal surface (ant)
ischium landmarks
- body of ischium (near acetab.)
- ischial spine
- lesser sciatic notch
- ischial tuberosity
- ischial ramus (branch to pubis (in back of pubic branch) (ischiopubic ramus in adult)
pubis landmarks
- superior pubic ramus (lat)
- pubic tubercle (very ant. near midline)
- body of pubis (branch)
- inferior pubic ramus (branch) (ischiopubic ramus in adult)
definition of pubis, ilium, ischium body
initial center of ossification
inguinal lig from where to where
ASIS to pubic tubercle
pubic crest def
pubic tubercle to midline (where rectus abdominis attaches)
pubic arch def
angle between two ischiopubic rami on either side (two pubis)
name of ischial ramus and pubic ramus in the adult
ischiopubic ramus (bc now fused)
hole between pubis and ischium
obturator foramen
landmarks of hip bone from an internal view (placed in middle of hip bone and looking at one side from inside)
- iliac fossa
- ASIS
- iliac tuberosity (attachment of posterior sacroiliac ligaments) (below iliac crest)
- symphyseal surface (articular surface of the pubic symphysis)
- auricular surface of the ilium (articular surface of the sacroiliac joint)
pubic symphysis is what
cartilage. it’s an immobile fibrocartilagenous joint between the two pubis
sacroiliac joint is what type of joint
synovial (diff from symphyseal joint)
2 lines visible from internal view of hip bone
- ARCUATE line (from auricular surface of the ilium to the top of obturator foramen)
- PECTINEAL line (from arcuate line (top of obt foramen) to symphyseal surface)
landmarks on the sacrum
- ala of the sacrum (near SI joint)
- sacral promontory
- body of the sacrum (midline)
- lumbosacral joint (between L5 and S1) + its intervertebral disc
- sacral canal (hole in midline with spinal cord)
- anterior and posterior sacral foramina (holes)
landmarks on coccyx
sacrococcygeal joint (cartilagenous joint), between the coccyx and the sacrum
how to orient the pelvis correctly
ASIS and pubic tubercle on the same vertical plane (coronal)
pubic arch facing the ground
pelvic inlet (brim) and pelvic outlet def
circle of the superior hole of pelvis and inferior hole of pelvis (inferior hole more diamond shaped)
(EXAM) what bones form the pelvic inlet (pelvic brim)
- sacral promontory
- ala of sacrum
- arcuate line
- pectineal line
- pubic symphysis
(EXAM) what bones form the pelvic outlet (diamond shaped)
- pubic arch (ant)
- ischial tuberosity and ST lig (lat)
- tip of coccyx (post)
2 triangles in pelvic outlet
- genital triangle in front
- anal triangle in the back
male vs female pelvis
- male = squashed, narrow, deep
- female = oval, wide, shallow, roomy
ligaments of the pelvis
- iliolumbar lig (lumbar vert to ilium). quadratus lomborum attaches there
- anterior and post sacroiliac lig (from sacrum to ilium)
- inguinal lig
- ST lig
- SS lig
SS vs ST orientation
SS is deep to the ST (so more anterior than ST). both form the two sciatic foramens (greater and lesser)
fct of SS and ST ligs
push sacrum outwards when pressure of the body pushes down on the pelvis
piriformis m. O and I
- from anterolateral surface of the sacrum
- out of greater sciatic foramen
- inserts (tendon) on greater trochanter of the femur
3 gaps in the 2 sciatic foramens
- above and below piriformis
- lesser sciatic foramen
coccygeus m. is O and I
O: SS lig and ischial spine. it points to the ischial spine
I: lat margin of the coccyx + related border of the sacrum
obturator internus m. O and I
- O: inside pelvis around obturator foramen
- I: greater trochanter of the femur
how obturator internus exists the pelvis
through the lesser sciatic foramen
what coccygeus m. helps form
pelvic floor, medially to the arcuate line. very bottom
fcts of piriformis m. and obturator internus m.
lateral rotators of the thigh
where sacral nerves come out of pelvis
anterior to piriformis m.
obturator membrane is what
membrane filling the obturator foramen partially. the hole left on top is the actual obturator foramen
obturator n. inn. what m.
medial thigh ADDuctors.
how obturator n. reaches the medial thigh ADDuctors
through the obturator foramen
2 muscles making up the pelvic floor
- levator ani (3 parts)
- coccygeus
tendinous arch def + runs where
- band of thickened CT from the deep fascia of obturator internus. it is medial to the arcuate line
- runs from ischial spine to the back of the pubis bone
function of tendinous arch
attachment point for pelvic floor muscles
muscles visible from top of pelvis looking down
back to front looking at the floor
- piriformis
- coccygeus
- obturator internus (lat) and levator ani iliococcygeus
coccygeus O and I
O: SS lig and ischial spine. it points to the ischial spine
I: lat margin of the coccyx + related border of the sacrum
obturator internus O and I
- O: inside pelvis around obturator foramen
- I: greater trochanter of the femur
levator ani iliococcygeus O and I
- O: tendinous arch
- I: inner surface of the coccyx
levator ani 2 other parts
pubococcygeus
puborectalis
pubococcygeus and puborectalis O and I
pubis to sacrum
2 hiatus formed by levator ani
- anal hiatus (for anal canal)
- urogenital hiatus (for urogenital system)
how to know how a pelvis is positioned in anat exam
- look for the pubic symphysis
2. look at the urve of the sacrum
order of position of rectum, cervix and urethra
anterior to posterior
- urethra
- cervix
- rectum
- all surrounded by levator ani*
pelvic arteries from aorta to femoral a.
- abdominal ao gives 1. ovarian aa (testicular arises from ao but DOES NOT enter the true pelvis. goes in inguinal canal) 2. superior rectal a. via the IMA 3. median sacral a. 4. common iliac aa
- common iliac aa gives internal and external iliac aa
- external iliac aa gives femoral a, deep circumflex a, inferior epigastic a
branches of the internal iliac a. by branching groups
ant. and posterior. branches of the internal iliac
post intern. iliac a. branches
- iliolumbar a. (up)
- superior gluteal a.
- lateral sacral a. (down on sacrum) (with branches to the sacral foramena)
ant intern. iliac a. branches
- obliterated umbilical a.
- obturator a.
- uterine a. (in females)
- vaginal a.
- middle rectal
- internal pudendal a.
- inferior gluteal a.
branches of the obliterated umbilical a.
vesical aa
branches of the uterine a.
vaginal branch of the uterine a. (is diff from vaginal a. from ant internal iliac a.)
where sup gluteal a. leaves the pelvis
above piriformis
internal pudendal a. position
close to ischial spine and coccygeus
arteries in pelvis from front to back
- obturated umbilical a.
- superior vesical a. (from oblit. umbilical a.)
- obturator foramen with obturator a.
- uterine a with its vaginal branch + vaginal a.
accessory obturator a. def
- the usual obturator a. is at its normal position
- an extra obturator a. (accessory) is present, it comes from the inferior epigastric a. (which is from external iliac) and it crosses the pubis posteriorly from top to bottom
aberrant obturator a. def
-obturator a. only present at one place, wrong place: off inferior epigastric a., off external iliac a.
pelvic arteries in males diff with female
- obturator a. comes off the inferior gluteal a.
- internal pudendal a. comes off the middle rectal a.
- no uterine and vaginal a.
- the inferior vesical a. is certain in males (but not sure if present in females)
inferior gluteal a. and internal pudendal a. ways they take
- inferior glut a. out of pelvis under piriformis
- internal pudendal a. out of greater sciatic foramen also below piriformis but then back in lesser sciatic foramen to feed pelvic floor (perineum)
sup and inf vesical aa go where
to the bladder
median and lat sacral aa origins
- median sacral a. from abdominal ao (branches to sacral body)
- lat sacral a from posterior internal iliac a. (branches to sacral foramina)
veins names in pelvis (pelvic veins)
same as adjacent arteries
-all go to internal iliac v, common iliac v., IVC
pelvic veins that don’t drain in the systemic circulation (IVC)
superior rectal v.. goes to IMV to splenic v to portal circulation (rectum part of digestive tract)
