General Anatomy

PELVIC
WALL
Anatomy Group
Dr Naser Radwan, MD
Dr Amjad Abu Alqumboz, MD
Dr Adham AlZanoun, MD
 Pelvis
• The pelvis is the region of the trunk
that lies below the abdomen.
The bony pelvis's main function:
 Contains, supports, and protects the pelvic viscera,
the lower parts of the intestinal tract, the urinary
tracts & the internal organs of reproduction.
 Transmit the weight of the body from the vertebral
column to the femurs.
 Provides attachment for trunk and lower limb
muscles. 2
 Bony Pelvis
• The bony pelvis forms a
strong basin-shaped
structure.

• Composed of 4 bones:
 The 2 hip bones, which
form the lateral and
anterior walls.
 The sacrum and the
coccyx, form the back
wall.
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 Divisions of the pelvis

Greater (False) Lesser ( True )

pelvis pelvis

• Lies above the • Lies below the

level of pelvic brim level of pelvic brim
(pelvic inlet) (pelvic inlet)
True Pelvis

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 False Pelvis
• It is of little clinical importance.
• It is bounded:
Behind by the lumbar vertebrae.
Laterally by iliac fossae and iliacus muscles.
In front by the lower part of the anterior
abdominal wall.
• The false pelvis supports the abdominal
contents and after the third month of
pregnancy helps support the gravid uterus.
 True Pelvis
• The true pelvis has an :
1) inlet 2) outlet 3)cavity
• It is bounded:
 infront and below : symphysis pubis , pubic
body and rami
Behind and above : pelvic surface of sacrum &
coccyx
On each side : pelvic surface of ilium & ischium
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 Pelvic inlet
The pelvic inlet, or pelvic brim is bounded:
 Posteriorly by the sacral promontory.
 Laterally by the iliopectineal lines.
 Anteriorly by the symphysis pubis.

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 Pelvic outlet
The pelvic outlet is
bounded
 Posteriorly by the
coccyx.
 Laterally by the
ischial tuberosities.
 Anteriorly by the
pubic arch.

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 Hip Bone
Each hip bone
consists of:
Ilium, which lies
superiorly.
Ischium, which
lies posteriorly
and inferiorly.
Pubis, which lies
anteriorly and
inferiorly. 10
 Hip Bone
• The three separate
bones are joined at the
acetabulum.

• Acetabulum is a deep
depression on the
outer surface of the hip
bone which articulates
with the head of the
femur. 11
 The ilium

• It is the upper flattened part of the hip bone

• It possesses the iliac crest.
• The iliac crest runs between the anterior and posterior
superior iliac spines. 12
 The ilium

• Below these spines are the corresponding anterior and

posterior inferior iliac spines.
• On the inner surface of the ilium is a surface for
articulation with the sacrum. 13
 The ischium
• The ischium is
the inferior and
posterior part
of the hip bone.

• It possesses an
ischial spine
and an ischial
tuberosity.
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 The pubis
• The pubis is the anterior and
inferior part of the hip bone
• It has a body and superior
and inferior pubic rami.
• The body of the pubis bears
the pubic crest and the pubic
tubercle.
• It articulates with the pubic
bone of the opposite side at
the symphysis pubis.
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 Symphysis Pubis
• is a cartilaginous joint between the two pubic bones.
• The articular surfaces are covered by a layer of
hyaline cartilage and are connected together by a
fibrocartilaginous disc.
• Almost no movement is possible at this joint.
 Pubic tubercle
• It can be felt on the upper
border of the pubis .
• The medial end of the inguinal
ligament is attached to it.
• The tubercle can be palpated
easily in the male by
invaginating the scrotum from
below with the examining finger.
• In the female, the pubic tubercle
can be palpated through the
lateral margin of the labium
majus.
• pubic crest is the ridge of the bone on the superior surface
of the pubic bone, medial to the pubic tubercle
 Sciatic Notch
• Behind the acetabulum is a
large notch, the greater
sciatic notch, which is
separated from the lesser
sciatic notch by the spine of
the ischium.
• The sciatic notches are
converted into the greater
and lesser sciatic foramina
by the presence of the
sacrotuberous and
sacrospinous ligaments. 19
 Sacrum
• Consists of (5)
rudimentary vertebrae
fused together to form
a single wedge-shaped
bone with a forward
concavity.
• The upper border or
base of the bone
articulates with the 5th
lumbar vertebra.
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 Sacrum
• The narrow inferior
border articulates
with the coccyx.

• Laterally, the
sacrum articulates
with the two iliac
bones to form
sacroiliac joints.
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 Coccyx
• It consists of four vertebrae fused together
to form a small triangular bone.
• It articulates at its base with the lower end of
the sacrum.
• The coccygeal vertebrae consist of bodies
only.

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 Pelvic Walls
• The pelvic walls are
formed of a framework of
bones , ligaments , joints
and membranes which
lined by muscles

The pelvis has :

- Anterior wall - Posterior wall
- Lateral walls - Inferior wall (floor)
 Anterior Pelvic Wall

• is the shallowest
wall and is
formed by the
bodies of the
pubic bones, the
pubic rami, and
the symphysis
pubis
 Posterior Pelvic Wall
• is extensive and
is formed by the
sacrum and
coccyx and by
the piriformis
muscles and
their covering of
parietal pelvic
fascia
 Lateral Pelvic Wall
• is formed by :
- part of hip bone below the
pelvic inlet
- obturator membrane
- sacrotuberous ligament
- sacrospinous ligament
- the obturator internus
muscle and its covering
fascia.
Lateral Pelvic Wall
 Inferior Pelvic Wall (Pelvic Floor)
• It supports the pelvic viscera
• It is formed by the pelvic
diaphragm.
• The pelvic floor stretches
across the pelvis and divides
it into:
 The main pelvic cavity
above, which contains the
pelvic viscera.
 The perineum below.
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 Inferior Pelvic Wall (Pelvic Floor)

Pelvic Diaphragm
• It is formed by the
important
levatores ani
muscles and the
small coccygeus
muscles and their
covering fasciae.
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Pelvic Walls and Floor Muscles
Piriformis muscle
obturator internus muscle
 Levator Ani Muscle
• Origin:
1. Anterior fibers: inner surface
of body of pubis.
2. Middle fibers: white line of
thickened obturator fascia.
3. Posterior fibers: inner surface
of the ischial spine.

• Course of fibers:
Downwards, backwards and
medially.
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Levator
Ani
Muscles

34
Levator
Ani
Muscles

35
 Levator Ani Muscle
• Insertion: The muscle consists of three parts:
1. Anterior fibers
the levator prostatae or sphincter vaginae form a sling
around the prostate gland or vagina and insert into a mass of
fibrous tissue, called the perineal body, in front of anal canal.
2. Intermediate fibers:
the puborectalis forms a sling around the junction of the
rectum and anal canal. The pubococcygeus passes posteriorly
to insert into a small fibrous mass, called the anococcygeal
body, between the tip of the coccyx and the anal canal.
3. Posterior fibers:
iliococcygeus inserts into the anococcygeal body and coccyx.
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 Levator Ani Muscle
• Nerve supply:
1. Upper (pelvic) surface: S4 nerve.
2. Lower (perineal) surface: Inferior
rectal N.

• Actions:
1. It supports the pelvic viscera.
2. It increases the intra-abdominal
pressure, so it's used in defecation,
micturition & labour.
3. The puborectalis is an additional
anal sphincter.
4. It is a sphincter for the vagina. 37
Coccygeus muscle
 Joints of the Pelvis
• Sacro-iliac joint

• Symphysis Pubis

• Sacro-coccygeal
Joint
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 Pelvic Peritoneum (male)
• The peritoneum lining the
lower part of the anterior
abdominal wall is reflected
backwards to cover the upper
surface of the urinary bladder

• The peritoneum is then

reflected backwards &
downwards above the seminal
vesicle forming recess called
(Recto-vesical pouch)
 Pelvic Peritoneum (male)

• Then it is reflected upwards to cover the front of the

middle 1/3 of the rectum then covers the front &
sides of the upper 1/3 of rectum.
 Pelvic Peritoneum (female)
• The peritoneum is reflected
from the lower part of the
anterior abdominal wall to
cover the upper surface of
urinary bladder (as in male).
• from the upper surface of
urinary bladder the
peritoneum passes backwards
to the front of uterus at the
junction of the body with the
cervix of uterus.
 Pelvic Peritoneum (female)
• Then it is reflected forwards on
the undersurface of uterus
forming recess ( Utero-vesical
pouch ).
• Then peritoneum covers the
following surfaces :
- Anterior surface of body uterus
- Fundus of uterus
- Posterior surface body and cervix
of uterus
- Upper ¼ the posterior surface of
the vagina
 Pelvic Peritoneum (female)

• Then it is reflected on to the front of the middle 1/3 of

rectum forming deep recess (Recto-uterine pouch =
Douglas pouch)
 Arterial Supply of Pelvis
Internal iliac artery
• ORIGIN : At sacroiliac
joint as the smaller of
the 2 terminal branch of
common iliac artery
• It divides into anterior
& posterior divisions
which gives the
terminal branches
 Arterial Supply of Pelvis

Branches
of Internal
iliac artery
 Biologic Sex Differences
• The more obvious
differences result from
the adaptation of the
female pelvis for
childbearing.

• The stronger muscles in

the male are responsible
for the thicker bones and
more prominent bony
markings
 Biologic Sex Differences
Male pelvis Female pelvis
General Heavier & stronger Lighter & thinner
False pelvis deep shallow
Pelvic inlet heart shaped transversely oval
Pelvic cavity Deep and funnel- Shallow & tubular
shaped
Pelvic outlet Smaller (narrower) Larger (wider)
Ischial spine More inverted Less inverted
Sacrum Wide , short , flat Narrow , long , curved
Pubic arch Narrow Rounded & wide
Biologic Sex Differences
 Perineum
• It is the region
which overlies
the pelvic
outlet.

• It has a
diamond-
shaped
outline
 Perineum
• Boundaries :
- Angles :
anterior Angle : formed by lower border of
symphysis pubis and inferior pubic ligament
posterior angle : formed by tip of coccyx
2 lateral angles : formed by ischial tuberosities
- Borders :
2 anterolateral : formed by pubic arch
2 posterolateral : formed by sacrotuboerus
ligaments
 Perineum
• Divisions :
line between 2 ischial
tuberosities divides the
peineum into 2 triangles

 Uro-genital triangle
Anal triangle
 UROGENITAL TRIANGLE
• is the anterior half of the
perineum.
• Boundaries :
anterior >> the pubic arch
lateral >> ischiopubic rami
and ischial tuberosities.
• The urogenital openings lie
in the midline, in close
relation to external genitalia.
 UROGENITAL TRIANGLE
The urogenital triangle is
organized into several layers:
• Skin
• Superficial perineal fascia
• Deep perineal fascia ??
• Superficial (inferior)
perineal space (pouch)
• Deep (superior) perineal
space (pouch)
 Superficial perineal space (pouch)
• is the zone between the superficial perineal
fascia (Colle’s fascia) and the perineal
membrane

Deep perineal space (pouch)

• It is a closed space , lies between perineal
membrane & urogenital diaphragm (that lies deep
(superior) to the superficial perineal space)