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Quick review from the previous lecture….
we said that the true pelvis doesn’t have a roof, rather its continuous with the
false (greater) pelvis through which we call it the pelvic inlet or brim. The
anterior wall of the pelvic wall we said that it’s made of pubic symphysis and 2
(V) shaped pubic bones. Posteriorly, it’s made of sacrum, coccyx and the
piriformis muscle(passing through the greater notch. The lateral wall is formed
mainly by the obturator internus muscle with it’s covering fascia.
Now let’s start with the inferior pelvic wall ( the floor )….
The floor is formed by which we call it the diaphragm → but its opposite to
the thoracic diaphragm, how ? this one is concave superiorly, so like a bowl.
now most of the walls are formed by bones and
muscles, except the floor, it’s mainly muscular.
this diaphragm divides the true pelvic cavity
into main pelvic cavity and perineum (later).
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Inferior view
Now the main muscle components of the diaphragm…
1- The coccygeus muscle:
 It’s called also the ischiococcygeus, why? because it’s arising from the
ischial spine to the coccyx & Lat. Lower sacrum.
 It’s a small triangular muscle
 It lies on the inner surface of the
 sacrospinus ligament, which separate the
greater sciatic foramen above from the
lesser below.
 Innervation: branches of S4 & S5.
 Actions: support pelvic viscera and slightly flexes coccyx.
2- Levator ani muscle:
 The main muscle, wide muscular sheet.
 It’s divided into 3 parts.
 Origin :
Pubic bone (ant.)→Tendinous arch of obturator fascia(dividing the
obturator muscle into superior and inf. parts →Ischial spine(post.).
* the thickened part of the obturator fascia to give an origin to the
levator ani we call it tendinous arch of obturator fascia.(green line).
 Insertion:
The muscle will spread medially, until it Reaches the midline, there it
will fuse With the muscle of the opposite side.
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→if you look to the inferior view: a gap is present anteriorly between the 2
levator ani , and this gap will provide a passage (hiatus) of the urethra and
vagina → called urogenital hiatus.
→Now in the middle part and posterior part when the muscles fuse they will
form a very strong fibrous ligament but is interrupted by the anal orifice.
→So the fibrous ligament will be divided into anterior part which we call it the
perineal body and the tendinous attachment behind the anus which is
continuous with the coccyx we will call it the anococcygeal body or ligament.
→Notice that we have a thickening in the origin and one(divided into 2) in the
insertion.
Now divisions of the levator ani muscle:
Anterior division: Short muscular slips From pubic bone  blend with fascia
around strc. In the midline. Surrounds the vagina in the female and prostate in
males.
Subdivided into:
A- Pubovaginalis (sphincter vaginae, beacause it acts as a sphincter) or
puboprostaticus (levator prostatae, beacause it elevates the prostate in
addition to anus). Notice the names indicate origin and insertion.
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B- puboperinealis muscle: some fibers goes to the perineal body
C- Puboanalis: to the anus. Few fibers.
the previous two are not important
- Intermediate division: from the pubic bone. Divided into 2 parts
a) puborectalis: thick narrow part forms a sling around the ano-rectal
junction → it will pull this junction forward → angulation btw the
rectum and anal canal → we refer to it as the anorectal angle 80o.
IMP. WHY ? → Maintains fecal continence, destruction to this muscle
causes fecal incontinence.
the sling is thick in vertical dimension but in a transverse dimension
it’s narrow.
b) Pubococcygeus: →thinner & wider
from the pubic bone & ant.part of tendinous arch to → the
anococcygeal body.

-posterior
division: (the iliococcygeus).
 From post. tendinous arch & ischial spine →to anococcygeal & coccyx.
 More aponeurotic than muscular → rare muscle fibers.(dense regular
C.T .→ support and resist downward pressure during inspiration
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In general the levator ani has 3 main functions :
1- Support and resist downward pressure caused by inspiration when the
thoracic diaphragm contracts. In females, helps in child bearing.
2- Formation of anorectal angle by the puborectalis part.
3- Sphincteric functions around anus, vagina, urethra.
Innervations of levator ani muscle:
 Mainly by pudendal nerve ( by inferior anal(rectal) nerve).
 Fibers from S4 called nerve to levator ani.
As we said the levator ani will divide the true pelvic cavity into 2 parts:
 Upper main pelvic cavity
 Lower cavity ( the perineum) → the main nerve is the pudendal nerve
(the nerve of shame)
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Summary
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Pelvic fascia
 It covers the pelvic cavity and wall. Composed of two parts :
Parietal & visceral.
- The parietal fascia :
 will cover the muscles forming also the deep fascia of the muscles
themselves and it will take the name of the muscle it covers. The
green layer in the figure.
 How many muscles we have ?
posteriorly piriformis → so we should have a piriformis fascia
lat. → obt. Internus → so we should have obturator fascia → in the
middle of this muscle it will thicken forming the tendinous arch.
 Notice the perineum under the levator ani , notice the sup. & inf. Fascia
of the levator ani → they are continuous with each other where ?
through the anterior gap ( the urogenital hiatus) .
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- the visceral layer:
 Covers and supports visceral organs like prostate, uterus &bladder.
 It will become the adventitia of these organs
 In certain locations it will thicken and extend from the visceral layers to
the parietal fascia → now it will become a ligament why we need these
ligaments ? to suspend the organs in their places.
 we have 4 important ligaments :
1- pubovesical (in females) &puboprostatic ligament ( in males)
extends from pubic fascia down towards the neck of bladder or prostate.
2- different ligaments in females :
 important in supporting the uterus and vagina in their middle position in
the pelvic cavity btw the bladder ant. And the rectum post. .
a) pubocervical ligament : from the pubic bone → obturator fascia → cervix
& it’s lateral to the pubovesical .
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b) Another one which arises from the posterior pelvic cavity,
the sacrocervical ligament,
c) The third one comes from the lateral abdominal wall which is,
The transverse cervical (cardinal L.) (principal L.).
if you cut the cardinal ligament you will see an artery and vein inside It,
which is the uterine artery.
Clinical note: this is important because
when you need to ligate this artery and
vein during hysterectomy . however we
know that the ureter passes under this
artery and ligament so you have to avoid
it. And this is known as “the water and the
bridge”. ( water: ureter, bridge: cardinal L)
Quick review:
Pelvic space:
 Greater ( false) pelvis is not part of the pelvic cavity rather it’s a part of
the abdominal cavity.
 True pelvis: divided by the pelvic diaphragm into upper main pelvic
cavity and lower the perineum.
 The pelvic brim seperates between the true and the false pelves.
And the borders of the brim are :
 Posteriorly: the promontory of the sacrum with it’s wings .
 Anteriorly: upper edge of the pubic symphesis
 Laterally: the iliopectineal line ( part is iliac and is called the arcuate
line and the pubic part is called the pectineal line).
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cont….
The pelvic wall:
 The pelvic girdle : the bony pelvis only → 2 hip bones, sacrum & coccyx.
They are joined by 4 joints they are:
 Anteriorly: pubic symphesis → secondary cartilaginous
 Posteriorly: the 2 sacroiliac joints → compound joint (anteriorly
synovial And posteriorly fibrous Syndesmoses with little
movement).
* Most of the joints in the pelvis they must have a little movement.
 Posteroinferior: btw the sacrum and the coccyx → sec.
cartilaginous, but why its fixed in its place although there should be
a movement? Because a dense “sleeve” of ligaments”‫”زي كم القميص‬
around this joint. But it may be disrupted.
 The muscles: 4 muscles:
1- The piriformis: located post. , innervated by nerve to piriformis ( it
comes from the L5,S1 and S2 , it was a H.W), function : lat. rotation
2- Obturator internus: on the lat. Wall
3- Coccygeus
4- Levator ani
form the diaphragm inferiorly.
 The fascia:
 Parietal fascia: covering the 4 muscles.
 Visceral fascia: 4 ligaments
Male&female : pubovesical or puboprostatic
Female: additional 3 ligaments. Mentioned previously.
It’s 3am → you have to appreciate this ,
yla appreciate
Now we move to gender variations
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Gender variations
Why is this? because of the physiological functions of child bearing and
pregnancy.
Male
Female
Thickness of hip bone
False pelvis
True pelvis
Pelvic Inlet (P. brim)
Pelvic outlet
Pubic angle
Much thicker
More prominent landmarks
why
Deep
Narrow, deeper, &
tapered(laterally And
anterioposteriorly) funnel
shaped in male
Wider and shallower
Wider, shorter & cylindrical
shape in Female >facilitate
birth
Heart-shaped
(android pelvis)
Oval to round shape in female
(Gynecoid pelvis)
More oval ( ant./post.)
Sharp <70 o (indicated by
index & middle fingers).
round
Wide >80 o (indicated by index
and thumb).
Notes:
 why male bone is thicker ? because of strong musculature pulling the insertions→ so
the bone is getting thicker.other examples : bicipital groove is getting deeper as the
biceps continue pulling…. Pubic tubercle and so on...and males especially have
stronger muscles by the action of androgens also .
 Why we have shallower false pelvis in females? Because it’s oriented more horizontal
of iliac bone
 Why its more tapered in males ? the sacrum more anteriorly and the ischial
tuberosities become more inverted. In females the tuberosities are more everted and
the sacrum is flatter.
 What makes the male outlet more oval? The ischial tuberosities, because they are
more inverted toward inside.
 The pubic arch is formed by the 2 inferior pubic rami. Forming the subpubic angle.
 Why pubic angle in females are wider ? because the ischial tuberosities are everted
outside > so the rami will move with it .
 So the ischial tuberosity determines the outlet and pubic angle as we see.
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look at this x-ray and the features we
talked ablout: the inlet , the angle ..
 to determine the horizontal
orientation of the iliac wings → you
draw a vertical line from the ASIS
downward you will see it passes
medial to the greater trochanter of
the femur in males
while in females it passes lateral to
the greater trochanter of femur
which indicates that the iliac crest is
more horizontal and wider.
 Other variations:
The sacrum: in females its more flat
While in males its curved more ant.
Forming the tapering of the pelvis.
The obturator foramen:
in males it’s round
in females → more oval or triangular
because the ischium is moving more
lateral and wider .
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pelvic fractures
 They don’t include the fractures of acetabulum → classified fractures of
the lower limbs.
 Pelvic fractures include the ring shaped bones of the pelvis.
 In the ring shaped bones like mandible or pelvis, when you have a
fracture in one side you always look for a fracture on the other side how
? if the fracture is anterior you look posterior.
Classifications of fractures :
2 types:
1. Stable fractures: most of the time doesn’t need surgical intervention and
they are one point fractures, just need medical stabilizing
2. Unstable: you need surgical intervention , and they are two points
fractures or more→ emergency sometimes
tile classification
Based on the stability of the sacroiliac joint: classified to A,B &C
Type A: if you have a fracture and the SI joint is intact . (stable)
Type B: if you have a partial distortion in the SI of the ant. Part of the joint (the
synovial part)
type C: complete distortion and separation of SI joint. (unstable)
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Stable pelvic fracture:
1. Fractures of the coccyx: the ligaments are weakened → distortion of the
joint, very rare.
 Patient will come with coccydynia(localized pain & infl. Sometimes)
 Typical history: falling down on buttocks.
2. transverse sacral fractures: very rare to happen due to its thick bone,
however when happen it doesn’t need treatment because the ligaments
are there supporting the bone→ no displacement
 just you tell the patient to sit on a smooth surface.
3. Duverney fracture: (iliac wings)
 A direct blow on the lateral side of the hip (crest)
 This was described by james duverney in 1751
 Why it’s stable ? no displacement, why ? due to presence of muscles
which are the iliacus and the gluteal muscles.
 Most of the time is stable unless you have a complication → injury to
a blood vessel → so you have to surgically interfere to stop the
bleeding.
4. Ipsilateral fracture: of pubic & ischial rami.
 On the same side of the ring.
 Stable → no surgical intervention, only symptomatic Rx. Unless there
is additional complication ( like soft tissue injury or hemorrhage)
look slide 30 for more pics.
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The unstable fractures: includes ( B&c )
1- Open book fracture: in three points
 Partially unstable
 Includes the anterior compartment of the SI
joints and the pubic symphysis
 We will have disrupted pubic symphysis
(pubic symphysis diastasis)
 When you have pubic diastasis the 2 pubic
bones will separate → they will tear the
anterior sacroiliac ligament. So the synovial
part will be separated so type B → partially
unstable.
 Rx: surgical intervention to close the book
and is stabilized with plate and screws.
2- Straddle fracture: (same as ipsilateral but both sides) ( ‫خيَّة‬
ِ ‫إِصا َبة َفرْ َش‬, ‫)الفسخ‬
 Double break of ant. Pelvic ring in both sides
 Usually in car accidents.
 This fracture is comminuted (small pieces)
 And since there is the bladder behind →
usualy associated with injury to the
urogenital viscera → so you have to deal with
the soft tissue first then reduction of bones.
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3- Vertical shear fracture: type C (completely unstable)
 2 point fracture : anteriorly the pubic rami and posteriorly all the SI
joint ( the synovial and the fibrous part) → so we call it hemipelvic
fracture
 The fractured segment will be pulled upward.
 The complication :
Minor : Upward dislocation of sacroiliac joint
& ipsilateral fracture of pubic rami
Major :
a) Fracture of the transverse process of L5.
b) Avulsion of ischial spine (destruction)
c) Stretching of sacral nerves
d) Hemorrhage : the most serious one! Because it may happen
from an artery (from the sup. Gluteal artery ).
Hemorrhage in pelvic fractures: 100% there is a bleeding in these fractures.
The mortality rate in PF  5-15% (high)   ½ due to hemorrhagic shock
Source of bleeding:
- Fractured bone
- Pelvic veins
90%
- Pelvic arteries: 10%
Most serious & leading cause of death in PF (especially in vertical shear
Fracture in which the sup. Gluteal artery( largest branch of internal iliac)
is the most common involved.
**emergency care otherwise death within 24 hrs
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‫‪The end‬‬
‫!‪Slide 53 next lecture‬‬
‫"لن تكون متدينا إال بالعلم ‪ ...‬فاهلل ال يعبد بالجهل" –مصطفى محمود‬
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