Intro to Pelvis and Pelvic Viscera Flashcards
Describe the pelvis
Bowl shaped region made by pelvic bones, ligaments and muscles
What is pelvis divided into
2 regions = false and true pelvis
Describe false pelvis
Greater
Superior to pelvic inlet
Part of abd cavity
Contains abdominal viscera, larger, rectum and sigmoid colon
Funnels into true pelvis
Bladder and ureters can extend into false pelvis - protrude into abd region
Describe true pelvis
Inferior to pelvic inlet
Continuous with abd cavity
Contains pelvic viscera
Has inlet and outlet - bony framework
Describe inlet of true pelvis
Comepletly surrounded by bones and joints
Defines upper border of true pelvis
Describe outlet of true pelvis
Closed by fibromuscular pelvic floor - pelvic floor seals outlet, maintains pressure of abdominal cavity, muscular pressure
Separates pelvic cavity to perineum below
Describe tilt of pelvis
Titled forwards, asis and psi’s in same plane as pubic tubercle
What is the hip bone
Pelvic bone, composed of 3 parts, 2 bones initially
Describe ilium
Articulates with sacrum - sacroiliac joint
Hand on waist, iliac crest
Describe pubis
Pubic tubercle -
Formed by 2 rami - superior and inferior form pubic symphysis and obturator foramen
Describe ischium
Forms the sit bone
Describe pubic tubercle
In front of pubic symphysis
When do all 3 parts of pelvis bone get fused
Fuse at 18 yo
Fused around acetabulum - hip joint, at 16-18 yo
Neonates and teens = not fused fully, takes time to make full bone
Name the easily palpable pelvic bone features
Iliac wing and crest
Describe iliac wing
Concave anterioly
Forms iliac fossa, where caecum and iliacus muscle are
Describe iliac crest
Superior edge of iliac wing, connects =
ASIS (ant sup iliac spine, ant end iliac crest) and PSIS (post sup iliac spine, post end iliac crest)
Describe pelvic inlet - brim
Bisects ilium and pubic regions respectively
Medial aspect pelvic, Seprates true and false pelvis
Describe ischial spine
Posterior bony projection
Separates above and below
= greater and lesser sciatic notches
Important insertion fo ligaments, very delicate, divides posterior pelvis into 2 notche
Describe ischial tuberosity
Sit bone
Large swelling postero inferiorly
Describe obturator foramen
Between pubic rami - closed by obturator membrane
At jucntion of ischial tuberosity and pubic bone, have big opening, O shaped
Faces medial thigh, n/v to medial thigh
Describe sacrum
Appearance of inverted triangle
Formed by fusion of 5 sacral vertebrae
Between each fused vertebrae = sacral foramina
What is function of sacrum
Keystone = push into sacrum and distribute weight - mechanical force on 2 sides of pelvis, pushes and distributes wight on the 2 pelvic bones, help maintain shape too
Describe joints of sacrum
Base articulates with l5
Apex articulates with Coccyx
Lateral surfaces articulate with pelvic bone via sacroiliac joints - 2 joints, wedges in here, synovial = forms pelvic girdle
Describe coccyx
Small terminal part of vertebral column
Formed by fusion 4 vertebrae
Describe joints of coccyx
Base articulates with sacrum
Describe pelvic girdle
Ring like bony frame formed by pelvic bones and sacrum
Sex speciic features different
Describe Afab pelvic girdle
Gynaecoid
Subpubic angle = angle between index and thumb = 90-100 degrees
Pelvic inlet more circular - larger pelvic outlet - wider, between inferior pubic rami
Overall is wide and shallow = allow for birth
Describe amab pelvic girdle
Subpubic angle = between index and middle finger = 70 degrees
Pelvic inlet more heart shaped - can tilt more
Overall is narrow and deep
Describe ligaments of pelvis - gen
Major compeonts of lateral wall
Need to keep pelvis upwards = ligaments to support, need solid framework, reinforced by anchors = keep upwards so prevent falling into false pelvis
Name ligaments of pelvis
Sacrospinous ligament
Sacrotuberous ligament
What is role of pelvic ligaments
Stabilize sacrum on pelvic bone - resisting tilting off sacrum
Close sciatic notches into sciatic foramina - closes notches
Openings for pelvic viscera
Where is greater sciatic foramen in relation to ligaments
Superior to sacrospinous ligamnent
Where is lesser sciatic foramen in relation to ligaments
Inferior to sacrospinous ligament and anterior to sacrotuberous ligament
Describe pelvic wall muscles generally
2 muscles contribute to pelvic wall
Muscles are originating in pelvic cavity but attach to femur
Describe obturator internus
From deep surface obturator foramen and membrane
Contributes to anterolateral pelvic wall
Leaves pelvic cavity throug lesser sciatic foramen - inserts on bony edge of opening
Covers obturator foramen
Reaches femur proximally
Describe piriformis
Post lat wall pelvic, pigeon pose,
From anterior surface of sacrum
Contributes to posterior pelvic wall
Leaves pelvic cavity through greater sciatic foramen
Divides greater sciatic foramen into 2 = above and below muscle
Also reaches hip joint, external rotation, int and ext rotation, depends on hip joint flexion, close to big sciatic nerve too
Describe pelvis gateways
Pelvic wall muscles sealing off almost the whole pelvis - forms like a bowl
Except for a few openings through pelvic wall
Describe obturator canal
Opening in obturator membrane covering obturator foramen
Describe greater sciatic foramen
Greater sciatic notch closed by sacrotuberous ligament and is divided into 2 by piriformis muscles = sup - superior gluteal region and inf = inferior gluteal region
Describe lesser sciatic foramen
Lesser sciatic notch closed by sacrospinous and sacrotuberous ligaments
Describe pelvic outlet - gateways
Inferior opening of true pelvis, closed by pelvic floor
Anterior = inferior bony border or pubis to ischial tuberosity
Posterior = sacrotuberous ligament, strong
What is pelvic floor formed by
Pelvic diaphragm muscles
Perineal membrane and deep perineal pouch
Describe pelvic diaphragm
Muscular part of pelvic floor consists of 2 muscles = levator ani and coccygeus
Seals outlet
Describe Levator ani
One on each side
Support viscera and maintain closure of rectum and vagina
Originate from pelvic wall, forming 3 units
Describe puborectalis - levator ani
Pubic bone and slinging behin rectum
Connects to contralateral side, slings behin rectum, prevents pubic incontinence
Describe pubococcygeus - levator ani
Pubic bone to coccyx
Describe iliococcygeus - levator ani
Tending us arch over obturator internus and ischial spine to coccyx
Muscle inserting on top of other muscle
Reinforces fascia of obturator internus - induce mechanical force, now thicker
Describe how levator ani connects - on sides
Each side of joint posterior to vagina and around anal aperture
Anterior u shaped opening = urogenital hiatus,urethra and vagina
Describe coccygeus
One on each side, overlies sacrospinous ligament
Originates from coccyx bone and distal end sacrum —> ischial spine
Inserts on base coccyx = wing tail, muscle
Outside = ligament, inside = muscle
Describe perineal memebrane
Seals the 2 bones = pubic and ischial tuberosity, outside levator ani, tough, fibrotic membrane, tight perineal region
Thick triangular fascial structure attached to pubic bones
Overarching urogenital hiatus
Posterior edge is free, inserts on midline to perineal body
Provides attachement for ext genitalia - so not weighing on muscles
Describe deep perineal pouch
Space between perineal membrane and pelvic diaphragm (levator ani)
contains thin muscular sheet = sphincters for urethra
Perineal body
Central tendon of perineum
Ct structure into which muscles of pelvic floor and perinuem attach
Junction between levator ani and perineal membrane, anchors the 2
Describe pelvic organs - overview
Contained within true pelvis, between opening s
Space contained between pelvic inlet and outlet
Describe pelvic organs - cavity
Inlet = pelvic brain
Outlet = bony border of pubis to ischial tuberosity, sacrotuberous lig
Contains = urinary, gi and repro systems
most ant = bladder, most post = rectum
Describe pelvic organs - afab
Uterus and vagina betwene bladder and anus
Describe pelvic organs - amab
Glands associated with repro system between bladder and rectum
Describe rectum
Most posterior element of pelvic viscera
Follows concave contour of sacrum
Describe anorectal junction
Pulled forward by levator ani - puborectalis sling, slinging of muscle induces kink
Forms 90 degree angle closing anal canal
Moves Anal canal into posterior direction as it passes through pelvic flor
Allows to hold feces in rectal ampulla
Describe defecation
Intra abd pressure increases
Puborectalis relaxes = anorectal jucntion straightens - 140 degrees
Relaxation of internal - involuntary - and external - voluntary - anal spinchters
Much weight of feces, int and ext sphincters cannot hold on own
When is anorectal angle straighter
When squatting during delectation
Describe bladder
On top of pubic bone, 1st organ
Most anterior element of pelvic viscera
Describe bladder when full vs empty
Full = expands into abd cavity, over pelvic brim inlet
Empty = entirely contained in pelvic cavity
What is bladder shaped like
3 sides pyramid tipped over one side
Describe apex of bladder
Directed towards pubic symphysis
Median umbilical lig suspends it to ant abd wall
Describe median umbilical ligament
To avoid unneeded weight and presssure on urinary sphincters, = suspend badder, so only weight of urine pushing on sphincter
Describe base of bladder
Inverted triangle
2 ureters enter bladder to each posterosuperior corners
Urethra drains from Lowe corner at neck of bladder
Describe trigone of bladder
Betwene openings = mucosa smooth, forms trigone, smooth structure
No detrusor since cannot pull on urethra or ureters = fixed in space, trigone connects them and urine flows easy, smooth funnel
What is muscle inside bladder
Except for trigone = detrusor muscle
Describe how ureters enter pelvis
Crossing the bifurcation of common iliac artery
Describe where pelvic portion uterers located
Located posterior - behind gonadal vessels, - water under the bridge, most posterior structure
Where do ureters enter bladder
To each posterosuperior corners
Describe inside the bladder - ureters
Inter uteri’s ridge connects the 2 urethral orifices = forms superior border of trigone
Name the orifices of bladder
Ureteral orifices - opening, kidney stones can be lodged
For urethra
Describe Sacrospinous ligament
From ischial spine to sacrum and Coccyx
Describe Sacrotuberous ligament
More superficial
Post post iliac spine, post surface sacrum and coccyx to ischial tuberosity
