ANATOMY - PELVIS Flashcards
Prior to pubity, what separates the 3 parts of the hip bone?
Triradiate cartilage
At what age do the hip bones fuse?
15-17 y/o
Which bone of the hip bone is the largest?
ilium
wing/ala of ilium - what attaches on the inner surface
iliacus muscle (iliac fossa)
wing/ala of ilium - what attaches on the outer surface
gluteal muscles
Mid-inguinal point + significance
half way between ASIS and PS
Palpate femoral artery here
Mid point inguinan ligament
half way between ASIS + PT
‘True leg length’
ASIS to medial malleolus
Which hip bone is the most anterior?
Pubis
what are the 3 parts of the pubis
pubic body (sup pubic crest –> PT)
superior pubic ramus
inferior pubic ramus
What foramen do the pubic rami enclose and what travels through it
obturator foramen
obturator aa, vv, nn
position of ischium in hip bone
posteroinferior
inf ischial ramus + inf pubic ramus –>
ischiopubic ramus
What are the 2 important ligaments related to the ischium?
Sacrospinous ligament (sacrum to IS) - GSF
Sacrotuberous ligament (sacrum to IT) - LSF
Pelvic girdle - what are the 4 articulations
2 x sacroiliac joints
sacrococcygeal symphysis
pubic symphysis
role of greater pelvis (false pelvis)
provides support for lower abdominal viscera
role of lesser pelvis (true pelvis)
pelvic cavity and pelvic viscera
pelvic inlet - anterior border
Pubic symphysis
pelvic inlet - posterior border
Sacral promontry + sacral wings
pelvic inlet - lateral border
arcuate line ilium, pectineal line, sup pubic ramus AKA iliopectineal line
pelvic outlet - anterior border
pubic arch
pelvic outlet - posterior border
tip of coccyx
pelvic outlet - lateral border
ischial tuberosity + sacrotuberous ligament
How many sacral vertebra
5
what does base of sacrum articulate with?
L5 Intervertebral disc
What does apex of sacrum articulate with?
coccyx
what does lateral sacrum articulate with
ilium
what are the 2 surfaces of the sacrum and the fundamental difference between them
posterosuperior dorsal surface = coarse
anteroinferior pelvic surface = smooth
what surface of sacrum is median sacral crest on
dorsal surface
what attaches to median sacral crest?
Supraspinatous ligament
what attaches to intermediate sacral crest?
posterior sacroiliac ligament
what attaches to lateral sacral crest?
posterior sacroiliac ligaments
sacrotuberous ligaments
which sacral articular processes arent fused>
S1 + S5
how many transverse lines on pelvic sacral surface?
4
what are the sacral transverse lines remenants of and when does this process begin?
fused sacral intervertebral discs
from age 20
3 muscles attaching to anterior sacral surface
piriformis (–> GT)
coccygeus (–>coccyx)
iliacus (–>LT)
2 muscles attaches to posterior sacral surface
multifidus lumbrorum
erector spinae
what is carried in the central canal of the sacrum
sacral fibres, cauda equinal
at what level does the dural sac terminate in the sacrum
S2
how many ganglia of the sympathetic trunks in the sacrum
4
what is the medial sacral artery a branch of
abdominal aorta posteriorly
what does medial sacral aa supply (before anastomoses w/ lateral sacral aa) (2)
posterior rectum
coccygeal gland
what is the lateral sacral artery a branch of?
internal iliac aa
what does the anastomoses of the sacral arteries supply
meninges
sacrum
how many vertebra fuse to form coccyx
4
embryological origin coccyx
caudate eminence
4-8w gestation
what do the coccygeal cornua articulate with?
sacral cornua via intraarticular ligaments
action of sacrococcygeal symphysis
minor passive flexion and extension
what are the 5 ligaments associated with the coccyx?
anterior sacrococcygeal ligament
deep posterior sacrococcygeal ligament
superficial posterior sacrococcygeal ligament
lateral sacrococcygeal ligament
intraarticular ligaments
anterior sacrococcygeal ligament
connects anterior aspects vertebral bodies
deep posterior sacrococcygeal ligament
post 5th VB sacrum –> dorsal coccyx
superficial posterior sacrococcygeal ligament
med sacral crest –> dorsal coccyx
lateral sacrococcygeal ligament
lateral sacrum –> TP Co1
what 3 mm attach to coccyx
gluteus maximus
levator ani
anococcygeal raphe
role anococcygeal raphe
help support position of anus
what is coccydynia
discomfort around coccyx
what is the most common presenting tumour in newborns?
sacrococcygeal teratoma
embryological origin sacrococcygeal teratoma
primitive streak
which structure separates the greater and lesser sicatic foramen?
sacrospinous ligament
GSF - superior border
anterior sacroiliac ligament
GSF - anterolateral border
greater sciatic notch (ilium)(
GSF - posteromedial border
sacrotuberous ligament
GSF - inferior border
sacrospinous ligament + ischial spine
which muscle divides the greater sciatic foramen into 2 sections?
piriformis muscle
suprapiriform GSF - contents (3)
superior gluteal aa, v, nn
infrapiriform GSF - contents (8)
inferior gluteal aa, vv, nn
nn obturator internus
nn to quadratus femoris
sciatic nn
pudendal nn
post femoral cutaneous nn
superior border LSF
sacrospinous ligament + ischial spine
anterior border LSF
ischial spine, lesser sciatic notch
posterior border LSF
sacrotuberous ligament
contents lesser sciatic foramen (5)
internal pudendal aa + vv
pudendal nn
nn to obturator internus
obturator internus tendon
significance of sciatic foramina + pudendal nn
pudendal nn leaves pelvis via GSF and then re-enters pelvis via LSF
what 2 muscle groups make up the pelvic floor>
levator ani
coccygeus
shape of pelvic floor
funnel shaped
what does pelvic floor separate?
pelvic cavity from perineum
2 holes in pelvic floor of significance
urogenital hiatus
rectal hiatus
what fibrous structure is between the urogenital and rectal hiatus?
perineal body
functions of pelvic floor (3)
support abdominopelvic viscera
resist increases in intra abdominal pressure
urinary and faecal continence with mm fibres –> sphincter action around urethra and rectum
inn levator ani mm
ant ramus S4
Pudendal nn S2-4
what 3 muscles constitute the levator ani
pubococcygeus
puborectalis
iliococcygeus
anterior attachment levator ani
pubic bodies
lateral attachment levator ani
tendinous arch obturator internus
posterior attachment levator ani
ischial spines
pre-rectal fibres
u shaped sling around urethra + vagina important in urinary continence
role puborectalis
bends anal canal anteriorly, maintaining faecal continence
role iliococcygeus
elevates pelvic floor + anorectal canal
which muscle is the main constituent of the levator ani?
pubococcygeus
coccygeus origin/insertion
ischial spines –> lateral sacrum + coccyx
innervation coccygeus
anterior rami S4/5
what is the most inferior part of the pelvic outlet
perineum
shape of perineum
diamond shaped
anterior anatomical border perineum
Pubic symphysis
posterior anatomical border perineum
tip of coccyx
lateral anatomical border perineum
inferior pubic rami
inferior ischial rami
sacrotuberous ligament
anatomical base of perineum
skin/fascia
anterior surface border perineum
mon pubs (f)
base of penis (m)
lateral surface border perineum
medial surface thigh
posterior surface border perineum
superior gluteal cleft
what structure divides the perineum into the anterior and posterior triangles?
ischial tuberosities
contents of anal triangle of the perineum (4)
anal aperture
ext anal sphincter
ischioanal fossa
pudendal nn
role of ischioanal fossa
allows for expansion of the anal canal during defacation
layers of the urogenital triangle of perineum (deep –> superficial) (5)
deep perineal pouch
perineal membrane
superficial perineal pouch
deep perineal fascia
superficial perineal fascia
contents deep perineal pouch (5)
urethra
external urethral sphincter
vagina
bulbourethral glands
deep transverse perineal muscles
what 2 structures perforate the perineal membrane?
vagina
urethra
role perineal membrane
provide attachment for muscles in the external genetalia
contents superficial perineal pouch (4)
ischiocavernosus
bulbospongiosus
transverse perineal muscles
Bartholins glands
what are the 2 layers of the superficial perineal fascia and what are they continuous with respectively
superficial layer - continuous with Campers fascia
Deep layer - continuous with Scarpas = Colles
what material is the perineal body
fibromuscular - SKM, SM, collagen + elastic fibres
which mm attach to perineal body? (5)
levator ani
bulbospongiosus
sup + deep transverse perineal mm
ext anal sphincter mm
ext urethral sphincter mm
nn supply to perineum
pudendal nn S2-4
aa supply to perineum
internal pudendal aa
sensory supply by pudendal nn
external genitalia
skin around anus
anal canal
perineum
motor supply by pudendal nn (5)
bulbospongiosus
ischiocavernosus
levator ani
ext urethral sphincter
ext anal sphincter
pathway pudendal nn
sacral plexus ant ramus S2-4
descends between piriformis + ischiococcygeus mm
through greater sciatic foramen
crosses sacrospinous ligament
re-enters via lesser sciatic foramen
accompanies int pudendal aa/vv anterosuperiorly to Alcocks canal where it divides
3 main divisions of pudendal nn
1 - inf rectal nn
2- perineal nn
3 - dorsal nn penis/clitoris
action inferior rectal nn
inn perianal skin
lower 1/3 anal canal
action perineal nn
skin perineum, labia + post scrotum
action dorsal nn penis/clitoris
skin penis or clitoris
afferent aspect of erection
which muscle is the sacral plexus anterior to?
piriformis
which nn roots/ant rami make up sacral plexus
ant rami S1-4
L4 + L5 lumbar roots
what are the 5 major nn that are formed by sacral plexus
Sometimes Izzy Shits Poo Persistently
Sup gluteal L4-S1
Inf gluteal L5-S2
Sciatic L4-S3
Post femoral S1-3
Pudendal S2-4
route superior gluteal nn
leaves pelvis via GSF –> gluteal region superior to piriformis via sup gluteal aa + vv
motor function superior gluteal nn (3)
gluteus minimus
gluteus medius
TFL
route inferior gluteal nn
leaves pelvis via LSF –> gluteal region inferior to piriformis w/ inf gluteal aa + vv
motor fct inferior gluteal nn
gluteus maximus
tibial portion sciatic nn - motor fct
mm post compartment APART FROM BICEPS FEMORIDS
Hamstring adductor magnus
all mm posterior leg + sole foot
tibial portion sciatic nn - sensory fct
skin post lateral leg
lateral foot
sole of foot
common fibular portion sciatic nn - motor fct
short head biceps femoris
ant + lat leg
EDB
common fibular portion sciatic nn - sensory fct
skin lateral leg
skin dorsum foot
route posterior femoral cutaneous nn
leaves pelvis via GSF –> gluteal region inferior to piriformis –> descends deep to gluteus maxmus –> down back of thigh to knee
posterior femoral cutaneous nn - sensory fct
skin post thigh + leg + perineum
other nn from sacral plexus not mentioned (3)
nn to piriformis
nn to obturator internus
nn to quadratus femoris
which artery is the major artery to the pelvis?
internal iliac aa
anterior trunk branches internal iliac aa (7)
obturator aa
umbilical aa –> sup vesical aa
inf vesical aa
vaginal aa (F)
uterine aa (F)
Middle rectal aa
Inf gluteal aa
posterior trunk branches int iliac aa (3)
iliolumba raa
lateral sacral aa
sup gluteal aa (terminal branch)
obturator aa supplies
adductor thigh region via adductor canal
sup vesical aa supplies
sup bladder
inf vesical aa suppplies
lower bladder
prostate
seminal vesicles
vaginal aa supplies (3)
vagina
inf bladder
rectum
inf gluteal aa supples
gluteus max + hip joint
what does iliolumbar aa branch off into + what do the branches supply
iliac branches - mm + bone around iliac fossa
lumbar branches - psoas major, quadratus lumbrorum + post abdo wall
lateral sacral aa supplies
structures in sacral canal
skin + mm post to sacrum
superior gluteal aa supplies
skin + mm gluteus medius + minimus
level that median sacral aa posterior branches off from abdo aorta
L2
where does ext iliac vv receive blood from (3)
inf epigastric vv
deep circumflex iliac vv
femoral vv
where vv is responsible for the majority of pelvic drainage
int iliac vv
sup/inf gluteal vv - drain where
buttock + upper thigh
int pudendal vv drains where
reprodcutive organs + inf rectum via inf rectal vv
lateral sacral vv drains
part of sacrum
middle rectal vv drains where
bladder, prostate, mid rectum
vesical vv drains where
bladder via vesical venous plexus
uterine + vaginal vv drain where
female reproductive organs
via vaginal/uterine venous plexus
where does common iliac vv form
at pubic symphysis
what drains into common iliac vv
ext + iliac vv
ilioluumbar vv
middle sacral vv
what level does Common iliac become ivc
L5
