The pelvis is the lower part of the trunk of the human body between the abdomen and the thighs. Topographically it is made up of a bony and ligamentous framework which is lined internally and externally by soft tissue and it is closed inferior by a layer of muscle and fascia which constitute the pelvic floor. The perineum lies below the pelvic floor. The pelvis in its broadest sense is an anatomical region bounded behind by the sacrum and coccyx, on each side and anteriorly by the innominate bones which are the hip bones, or pelvic bones. These bones form the skeletal base for the lower limb.

1. Dr. NDAYISABA CORNEILLE
CEO of CHG
MBChB,DCM,BCSIT,CCNA
Supported BY

2. PELVIS
• The pelvis is the lower part of
the trunk of the human body
between the abdomen and the
thighs.
• Topographically it is made up of a bony and
ligamentous framework which is lined
internally and externally by soft tissue and it is
closed inferior by a layer of muscle and fascia
which constitute the pelvic floor.
• The perineum lies below the
pelvic floor.
Dr Ndayisaba Corneille 2

3. Boundaries of the Pelvis
• The pelvis in its broadest sense is
an anatomical region bounded
behind by the sacrum and coccyx,
on each side and anteriorly by the
innominate bones which are the
hip bones, or pelvic bones.
• These bones form the skeletal
base for the lower limb.
Dr Ndayisaba Corneille 3

4. DIVISION OF THE PELVIS
• An imaginary plane passing
through the linea terminalis
(Pelvic Brim) divides the
entire pelvis into two parts:
– an upper larger part which is
referred to as the greater
pelvis also known as the
false pelvis or the pelvis
major and
– a lower smaller part which is
referred to as the lesser
pelvis, also known as the
true pelvis or the minor
pelvis
Dr Ndayisaba Corneille 4

5. • The linea terminales is
formed by the
– anterior border of the
base of the 1st sacrum
formed by (the sacral
Promontory and margin
of the ala),
– the arcuate line of the
ilium and
– the pectineal line of the
pubis.
Dr Ndayisaba Corneille 5

6. THE GREATER PELVIS (FALSE, MAJOR
PELVIS)
• This is the part of the
pelvis lying above the
linea terminalis.
• Posterior lies the 5th
Lumber vertebrate
• laterally it is bounded by
the iliac fossa while
• anteriorly where the ilium
is deficient it is bounded
by the lower part of the
anterior abdominal wall.
Dr Ndayisaba Corneille 6

7. CONTENTS OF THE GREATER PELVIS………………….
• It is generally considered part of
the abdominal cavity (because of
this, it is also called the false
pelvis).
• The greater pelvis contains
– Part of the ileum,
– Ceacum,
– Appendix and
– Sigmoid colon
Dr Ndayisaba Corneille 7

8. LESSER PELVIS
• It is part of the pelvis lying
below and behind the linea
terminalis.
• It is said to have superior
aperture or Pelvic inlet , Pelvic
cavity and an inferior aperture or
Pelvic outlet
• The true pelvis in females is
modified to serve as the birth
carnal.
Dr Ndayisaba Corneille 8

9. CONTENTS OF LESSER PELVIS
• The lesser pelvis contains the rectum, bladder, and some of the internal
genitalia (sex organs).
• The rectum lies in the curve of the sacrum and coccyx; the bladder is in front,
behind the pubic symphysis.
• In the female, the uterus and vagina occupy the interval between these
viscera.
Dr Ndayisaba Corneille 9

10. The superior aperture: Pelvic Inlet
• The superior aperture is formed
posteriorly by the anterior surface
of the base of the body of the 1st
sacrum,
• on each side (laterally) it is bounded
by the arcuate line and the pectineal
line
• while anteriorly it is bounded by the
pubic crest and the anterior
continuation of the pectineal line.
Dr Ndayisaba Corneille 10

11. Pelvic Outlet
• The pelvic outlet also known
as the inferior aperture is
bounded
– posterior by the tip of
coccyx,
– lateral by the ischial
tuberosity and
– anteriorly by the pubic arch
which is formed by the
ventral rami of the pubic and
the ischial bone as they unite
anteriorly.
Dr Ndayisaba Corneille 11

12. Dr Ndayisaba Corneille 12

13. OBSTETRICAL OUTLET:
• This outlet has greater practical significance,
because it includes the narrow pelvic strait
through which the fetus must pass.
• It is otherwise known as bony outlet.
• Shape: it is diamond shaped.
• It is bounded by the lower border of the
symphysis pubis anteriorly, the ischial
spines laterally, and the tip of the sacrum
posteriorly
Dr Ndayisaba Corneille 13

14. THE PELVIC CAVITY
• The pelvic cavity is the
continuation of the abdominal
cavity into the Pelvis through the
Pelvic brim or Pelvic inlet. It
extends from the pelvic brim
above to the Pelvic outlet below.
• The Abdominal cavity continues
inferiorly into the Pelvic cavity as
such they are sometimes referred
to as Abdominopelvic cavity
Dr Ndayisaba Corneille 14

15. Pelvic cavity……………………
• its shape is almost rounded. It
consist of
– Anterior border: Symphysis pubis
– Posterior border: Sacral hollow
– Lateral border: Soft tissues
• It has two openings: a Superior and
Inferior Aperture or Outlet
• This cavity is a short, curved canal,
deeper on its posterior than on its
anterior wall.
Dr Ndayisaba Corneille 15

16. Dr Ndayisaba Corneille 16

17. THE BONY PELVIS
• The bony pelvis is the irregular
bony griddle between the femoral
heads and the fifth lumbar
vertebra.
• It is massive because its primary
function is to withstand
compression and other forces due
to body weight, abdominal
powerful musculature and lower
limb musculature.
• It is of great importance in
obstetric, forensic and
anthropological applications.
Dr Ndayisaba Corneille 17

18. The bony pelvis………………..
• The bony pelvis is formed
by :
– the hipbone (pelvic bone) in
front and at the sides, and
– the sacrum and coccyx
behind.
Dr Ndayisaba Corneille 18

19. Pelvic Bone
• The two hip bones are
joined at the pubic
symphysis
• Hip bones articulate
with the sacrum at the
sacroiliac joints and the
femur at the hip joint
• It is composed of Ilium,
ischium and pubis and
they fused at the
acetabulum.
Dr Ndayisaba Corneille 19

20. THE PUBIS:
• It forms the anterior part of the pelvic
bone.
• Its body forms 1/5th of the acetabulum.
• Its symphyseal surface unites with the
opposite side to form the pubic
symphysis.
• The superior and inferior pubic rami
participate in the formation of the
obturator foramen.
• Its inferior ramus fuses with the ischial
ramus to form the ischiopubic ramus.
Dr Ndayisaba Corneille 20

21. HIP BONES: PUBIS
• Body of pubis
• Superior ramus of
pubis
• Inferior ramus of pubis
• Pubis crest
• Pubic tubercle
• Pecten pubis
(pectineal line of
pubis)
• Subpubic angle Dr Ndayisaba Corneille 21

22. The Ischium
• It is V-shape and forms the posterior inferior
part of the pelvic bone.
• It presents a roughened projection. The ischial
tuberosity that protrudes posteroinferiorly
from the body of the ischium.
• It is the site for attachment of the
sacrotuberous ligament; origin of the inferior
gemellus muscle, quadratus femoris muscle
and the hamstring muscles.
• Its posterior margin is marked by a prominent
ischial spine that separates the lesser sciatic
notch below from the greater sciatic notch
above.
Dr Ndayisaba Corneille 22

23. HIP BONE: ISCHIUM
• Body of ischium
• Superior Ischial
Ramus
• Inferior ischial
ramus
• Ischial spine
• Ischial tuberosity
Dr Ndayisaba Corneille 23

24. The Ilium
• It Is the most superior in
position.
• It presents the iliac crest which
runs between the antero- and
postero- superior iliac spines,
below each of these are the
corresponding inferior spines.
• Its inner aspect bears the large
auricular surface which
articulates with the sacrum.
Dr Ndayisaba Corneille 24

25. HIP BONE: ILIUM
• Ala of ilium
• Body of ilium
• Iliac crest
• Iliac fossa
• Anterior superior iliac spine
(ASIS)
• Anterior inferior iliac spine
(AIIS)
• Posterior superior iliac spine
(PSIS)
• Posterior inferior iliac spine
(PIIS Dr Ndayisaba Corneille 25

26. THE SACRUM
• It is formed by five fused sacral
vertebrae whose transverse
processes and fused costal processes
forms the alar plate or the lateral
mass.
• Anteriorly, is the anterior sacral
foramina which transmits the ventral
primary rami of the sacral spinal
nerve
Dr Ndayisaba Corneille 26

27. Posterior View
• Posteriorly the spinal processes fuse to form
the median sacral crest
• Present also is a posterior sacral
foramina which transmits the dorsal primary
rami,
• Caudally is the sacral hiatus which is formed
due to the unfused laminar of the 5th sacral
vertebrae. It is the sight for caudal anesthesia.
• It is located at the surface by an important
landmark formed by the sacral cornua formed
by the pedicle of the 5th sacral vertebrae.
• Second sacral vertebrate
marks the end of dura and
arachnoid mater as well as
the subarachnoid space
Sacral Canal
Dr Ndayisaba Corneille 27

28. Abnormalities of Sacral Bone
• Sacralization is a common irregularity of
the spine, where the transverse process of
the fifth lumbar vertebra fuse with the
sacrum
• The fifth lumbar vertebra may fuse fully
or partially on either side of the sacrum, or
on both sides.
• Lumbarisation is where the 1st sacral
vertebra fuses with the 5th Lumbar Vertebra
• Sacralization and lumbarization are
congenital anomalies that occurs in the
embryo.
• Unilateral or Bilateral lumbarisation
• Unilateral or Bilateral sacralisation
Dr Ndayisaba Corneille 28

29. THE COCCYX
• Coccyx is a vestigial
tail. It consists of
four fused vertebra
forming a small
triangular bone.
• its base articulates
with the lower end
of the sacrum.
Dr Ndayisaba Corneille 29

30. FUNCTIONS OF BONY PELVIS
• 1) To protect pelvic viscera
• 2) To support the weight of the body - transfer
the weight of the upper body from the axial to
the lower appendicular skeleton
• 3) Provides attachment for muscles
• 4) In females, it provide bony support for the
birth canal
Dr Ndayisaba Corneille 30

31. Pelvic joints
• There are four
pelvic joints
• Two sacroiliac
joints
• One sacro-
coccygeal joint
• One Pubic
symphysis
Dr Ndayisaba Corneille 31

32. Pubic Symphysis
• It is a secondary cartilaginous joint
• Articular surface is covered with
hyaline articular cartilage
• Disc of fibro-cartilage lies between the
articular surface
• A cavity may develop in the disc but it
is not lined with synovial membrane
• There is normally very little movement
at the pubic symphysis, except during
the latter months of pregnancy
Dr Ndayisaba Corneille 32

33. Sacroiliac Joint
• Modified synovial plane joint
• Articular surfaces are rough
• It bound by the Anterior and
Posterior sacroiliac
ligaments which is one of the
strongest ligaments in the
body
• This articulation is almost
immobile, except during
pregnancy
Dr Ndayisaba Corneille 33

34. Sacroiliac Joint Accessory Ligaments
• Sacrotuberous
ligaments
• Sacrospinous
ligaments
• Iliolumbar
ligaments
• The sacrotuberous and
sacrospinous ligaments
converts the greater and
lesser sciatic notches
to Foraminae
GS
F
LSF
Dr Ndayisaba Corneille 34

35. Sacro coccygeal joint
• The sacro coccygeal joint: this
joint is formed where the base
of the coccyx articulate with the
tip of the sacrum
• During labour the coccyx moves backwards at
the sacrococcygeal joint to give more space for
the delivery of the baby this is called nodding.
• Fracture of a fused sacrococcygeal joint or at the
fused coccygeal joints or arthritis in these joints
causes a painful condition known as
coccygodynia.
Dr Ndayisaba Corneille 35

36. Movement in the Pelvic Joint
• In the non-pregnant state there is very little movement
in these joints, but during pregnancy endocrine activity
causes the ligaments to soften, which allows for slight
movement.
• This may provide more room for the fetal head as it
passes through the pelvis.
• The symphysis pubis may separate slightly in later
pregnancy. If it widens appreciably, the degree of
movement permitted may give rise to pain on walking.
• The sacro-coccygeal joint permits coccyx to be
deflected backward during the birth of the head
Dr Ndayisaba Corneille 36

37. MEASUREMENT OF THE FEMALE PELVIS
• These values are of great importance
in obstetrics for predicting the
likelihood of a vaginal delivery.
• Accurate measurements of the mothers
pelvic inlet and outlet is determined in
other to know if the size and position
of the fetal head could cause
complications during delivery.
• These measurements include:
Dr Ndayisaba Corneille 37

38. MEASUREMENT OF THE PELVIC INLET:
• Conjugate Diameter:
– True conjugate
– Diagonal Conjugate
– Obstetric Conjugate
• Transverse Diameter
• Anatomical Transverse Diameter
• Obstetric Transverse Diameter
• Oblique Diameter
• Right Oblique Diameter
• Left Oblique Diameter
• Sacrocotyloid diameter
Dr Ndayisaba Corneille 38

39. True conjugate
• This is the anterior
posterior diameter
from the sacral
promontory to the
superior margin of
the pubic
symphysis. It is
about 11 to 11.5cm
in females, but in Dr Ndayisaba Corneille 39

40. Diagonal Conjugate
• This is measured from the sacral promontory
to the inferior margin of the pubic
symphysis. It is about 12cm.
Vaginal Examination to Determine Diagonal Conjug
Dr Ndayisaba Corneille 40

41. Obstetric Conjugate
• Obstetric Conjugate: This is the least A.P
diameter from the sacral promontory to a
point a few millimeters below the superior
margin of the pubic symphysis. It is about
10.5cm.
• It is shortest AP diameter through which
the head must pass.
• It cannot be measured clinically
• For clinical purposes, obstetric conjugate
is estimated indirectly by subtracting 1.5
to 2 cm from diagonal conjugate
• If the Obstetric conjugate is less than 10 cm,
it is called contracted pelvic inlet.
Dr Ndayisaba Corneille 41

42. Transverse Diameters: Anatomical and Obstetric T D
• Anatomical Transverse
Diameter is the widest
distance across the
pelvic brim. It is about
13 to 13.5cm in females
and in males it is about
12.5cm.
• The largest diameter of
pelvic inlet = Transverse
diameter
Dr Ndayisaba Corneille 42

43. Obstetric transverse diameter
• It bisects the
true
conjugate and
is slightly
shorter than
the
anatomical
transverse
diameter.
Dr Ndayisaba Corneille 43

44. Oblique Diameters: Right and Left O. D.
• The right oblique diameter passes from the right sacroiliac joint to the left iliopectineal
eminence and the left oblique extends from the left sacroiliac joint to the right
iliopectineal eminence. Each measures about 12cm.
Dr Ndayisaba Corneille 44

45. The Sacrocotyloid diameter
• The sacrocotyloid
diameter is
measured from
the sacral
promotory to the
iliopectineal
eminence, on the
same side, and is
approximately 9c
ms
Dr Ndayisaba Corneille 45

46. Diameters of the Pelvic
cavity
• The cavity extends from the brim
above to the outlet below. It is
almost circular in shape.
• The anterior wall is formed by the
pubic bones and symphysis pubis
and its depth is 4cm.
• The posterior wall is formed by the
curve of the sacrum which
is 12cm in length.
• The diameters, similar in direction to
Dr Ndayisaba Corneille 46

47. MEASUREMENT OF THE PELVIC OUTLET
• The pelvic outlet is slightly smaller than
the pelvic brim, but it would be unusual
for a fetal head to be able to pass through
the brim and not be able to pass through
the outlet.
• Antero-posterior diameter (13cm): it
Extend from lower border of symphysis
pubis to the tip of coccyx.
• Oblique diameter (12): it extend from Rt.
or Lt. Sacro spinous ligament to the
contralateral Obturator foramen
• Transverse diameter (11cm): between the
ischial spines.
Dr Ndayisaba Corneille 47

48. Dr Ndayisaba Corneille 48

49. ORIENTATION OF THE PELVIC
• In the anatomical position, the
pelvis should be placed in such a
way the anterior superior iliac spine
lies on the same vertical plane with
the top of the pubic symphysis.
• Though in the living the female
anterior superior iliac spine is tilted
a bit forward as a result of this the
lumbar curvature becomes more
curved and the buttock becomes
more prominent.
Dr Ndayisaba Corneille 49

50. VARIATION OF THE PELVIS
• The general shape of the pelvis is grouped into four base on
Caldwell- Moloy Classification of Pelvic Types
1. The Gynaecoid:
2. The Android:
3. Platypelloid:
4. Anthropoids:
Dr Ndayisaba Corneille 50

51. • Gynaecoid pelvis(50%)
• Anthropoid pelvis (25%)
• Android pelvis (20%)
• Platypelloid pelvis (5%)
Dr Ndayisaba Corneille 51

52. Gynaecoid pelvis: (50%)
• It is commonly known as the
female pelvis because that
type occurs most frequently
in women.
• Most suitable for childbirth.
• Wider brim.
• Ischial spines are blunt
• Sub pubic angle is greater
than 90 degrees
• Sub-pubic arch is wide enough to
accommodate the examiners four knuckles or
clenched fist
Dr Ndayisaba Corneille 52

53. Android pelvis: (20%)
• It is commonly known as
male pelvis because it
occurs more frequently in
men.
• Heart shaped brim
• Anterior posterior
diameter is shorter
• Transverse diameter is
wider
• Childbirth is difficult
Dr Ndayisaba Corneille 53

54. SEX DIFFERENTIATION
• This is of great important in forensic anthropology in order to
determine the sex of the pelvis in medicolegal situations.
• When presented with a pelvis for identification emphasis should be
laid on:
1. Pubic arch: to note its prominence as a result of attachment of crus of the
penis or clitoris.
2. The size of the acetabulum: which is larger in male than in female.
3. The distance between the acetabulum, ilium and the pubic symphysis:
which is longer in females than in males.
4. The size of the facet base of the sacrum in relation to the ala of the sacrum
(smaller in female and larger in male).
5. Subpubic angle it is the angle of the pubic arch which is larger in female
than in male.
Dr Ndayisaba Corneille 54

55. Dr Ndayisaba Corneille 55

56. MUSCLES OF THE LATERAL PELVIC
WALL
Obturator Internus Muscle and Piriformis
Dr Ndayisaba Corneille 56

57. Obturator Internus Muscle
• Origin: It takes its origin from the deep surface of
obturator membrane and its associated bony surface,
its fibers converge and pass through the lesser sciatic
foramen.
• Insertion: Inserted into the greater trochanter of
the femur just above the trochanteric fossa.
• Nerve Supply: Nerve to Obturator internus (L5,
L11, L12).
• Action: Because of its posterior medial insertion it
helps in abduction of the flexed hip and in lateral
rotation.
OIM
Dr Ndayisaba Corneille 57

58. Piriformi
s
PIRIFORMIS
It is a triangular shaped muscle which serves as
an important landmark in the gluteal region. Its
position should be compared with that of P minor.
Origin: From the anterior surface of 2nd – 4th
sacral vertebrae, lateral to the anterior sacral
foramina,
INSERTION: It passes to be inserted into the
greater trochanter of the femur just above the
insertion of the Obturator internus muscle.
Nerve Supply: Branches from ventral rami of L5,
S1 – S3.
Action: lateral rotator and abduction of the femur
Dr Ndayisaba Corneille 58

59. THE MUSCLES OF THE PELVIC FLOOR
• The pelvic floor is composed of
– the pelvic diaphragm,
• The pelvic floor separates the pelvic
cavity from the perineum.
• The muscles that forms the pelvic floor is
– the levator ani and
– the coccygeus muscle
Dr Ndayisaba Corneille 59

60. Dr Ndayisaba Corneille 60

61. LEVATOR ANI
• The levator ani
muscle is made
up of two parts,
– the lateral
portion and
– medial portion.
Dr Ndayisaba Corneille 61

62. the lateral portion of Levator ani
• The lateral portion arises from the
posterior and lateral aspect of the
pelvic bone and from the arcus tendinus
which is a condensation of the fascia
that covers the obturator internus
muscle (the white line).
• The part of the lateral portion which
arises from Pubic bone passes
backward forming a sling around the
anorectal junction this part of the
levator ani is referred to as the
puborectalis.
• It functions as a pinch valve and keeps
the anorectal junction at 90O angle,
thereby maintaining the continence of
feces within the rectum. Part of the
puborectalis insert into the external anal
sphincter to reinforce it.
Dr Ndayisaba Corneille 62

63. the lateral portion of Levator ani………
• The parts of the lateral portion
arising from the pubis and part of
the arcus tendinus passes
downward and backward as the
pubococcygeus to meet at the
midline behind the perineal body
to form the anococcygeal rephae.
• This raphae extends from the tip
of the coccyx to the anorectal
junction
• The part that arises from the ischial
spines and the posterior aspect of
the tendinous arch is referred to as
the iliococcygeus muscle it is
attached to the posterior aspect of
the tendinous arch
Dr Ndayisaba Corneille 63

64. Dr Ndayisaba Corneille 64

65. The medial portion of the levator ani
• The medial portion arises from
the pubic bone close to the
median plane.
• The medial portion of the
levator ani is also called the
Prerectal fibers of puborectalis.
• It forms a sling around the
prostate in males
(puboprostatea or around the
vagina- pubovaginae or vaginal
sphincter)
• Some part of it inserts into the
perineal body while some of it
blends with the longitudinal
muscle of the anal canal as the
puboanalis.
Dr Ndayisaba Corneille 65

66. • Nerve Supply: A branch from the pudendal
nerve known as the inferior rectal branch and
branches from the ventral rami of the 4th sacral
Nerve.
• Action: It helps to support the pelvic viscera
while the puborectalis function during
defecation process.
Dr Ndayisaba Corneille 66

67. THE COCCYGEUS MUSCLE
• It is a triangular shaped
muscle. It arises from the
ischial spine to be inserted
into the coccyx and the
adjacent part of the sacrum.
• It over lies the
sacrospinous ligament
• Nerve Supply: Ventral
branches of S4 and S5
• Action: It helps to pull
forward the coccyx during
defecation.
Dr Ndayisaba Corneille 67

68. Dr Ndayisaba Corneille 68

69. Functions
• The roles of the pelvic floor muscles are:
• pelvic floor support as well as aid in the sphincteric action
on rectum and vagina. Aids defecation, micturition and
parturition by increasing intra-abdominal pressure.
• Support of abdominopelvic viscera (bladder, intestines,
uterus etc.) through their tonic contraction.
• Resistance to increases in intra-pelvic/abdominal pressure
during activities such as coughing or lifting heavy objects.
• Urinary and faecal continence. The muscle fibres have a
sphincter action on the rectum and urethra. They relax to
allow urination and defecation
Dr Ndayisaba Corneille 69

70. Dr Ndayisaba Corneille 70

71. Episiotomy
• To avoid this pressure damage on pelvic
and perineal floor, during childbirth
episiotomy is normally employed to
avoid tearing the muscles.
• Age, number of normal vaginal
deliveries, weight, chronic cough, family
history of pelvic floor dysfunction are
notable risk factors.
• Damaged pelvic floor can be repaired
surgically and the muscles can be
strengthened through pelvic floor
exercises called kegel exercises.
Dr Ndayisaba Corneille 71

72. END
Dr Ndayisaba Corneille
THANKS FOR LISTENING
By
DR NDAYISABA CORNEILLE
MBChB,DCM,BCSIT,CCNA
Contact us:
amentalhealths@gmail.com/
ndayicoll@gmail.com
whatsaps :+256772497591
/+250788958241
72