1. The Pelvis: Part I-The
Pelvic Walls
Professor:
Dr. Mary Ann P. Aggarao, MD, MPH
Subj/sec:
DGA 111 / DAB
Prepared by :
Khafi Makoo , Noorallah

2. • The pelvis is
the region of
the trunk that
lies below the
abdomen.
• Although the
abdominal and
pelvic cavities
are continuous,
even the two
regions are
described
separately.

3. The main functions of the
pelvis are:
1. to transmit the weight of
the body from the
vertebral column to the
femurs;
2. to contain, support, and
protect the pelvic
viscera; and
3. to provide attachment for
trunk and lower limb
muscles.
The main functions of the
pelvis are:
1. to transmit the weight of
the body from the
vertebral column to the
femurs;
2. to contain, support, and
protect the pelvic
viscera; and
3. to provide attachment for
trunk and lower limb
muscles.

4. Pelvic Walls
• Anterior pelvic wall:
Formed primarily by the bodies and rami of
the pubic bones and the pubic Symphysis.
• Lateral pelvic walls:
Formed by the hip bones and the Obturator internus muscles:
Origin: Proximal surface of the ilium & ischium; obturator membrane.
Insertion: Greater trochanter of the femur.
Action: The obturator internus is a lateral rotator of the femur at the
hip joint.
Nerve supply: The muscle is supplied by the nerve to the obturator
internus, a branch from the sacral plexus.

5. Obturator Internus Muscle

6. Obturator Internus Muscle

7. Pelvic Walls
• Posterior Pelvic Wall:
Formed by the sacrum, coccyx, adjacent
parts of the ilia, Sacroiliac joints and Piriformis muscle:
Origin: Pelvic surface of 2nd and 4th sacral segments, superior
margin of the greater sciatic notch and sacrotuberous ligament.
Insertion: Greater trochanter of femur
Nerve supply: It receives branches from the sacral plexus.
Action: It is a lateral rotator of the femur at the hip joint.

8. Piriformis Muscle

9. Piriformis Muscle

10. Pelvic Floor
Formed by the funnel shaped pelvic diaphragm.
Pelvic Diaphragm:
Consists of the levator ani and coccygeus muscles
and their fascia.
Stretches between the pubis anteriorly and the coccyx
posteriorly and from one lateral pelvic wall to the other.
Three parts
1.Pubococcygeus
2.Puborectalis
3.Iliococcygeus

11. Levator Ani Muscle
Orgine: Body of pubis, fascia of obturator internus, spine of
ischium.
Insertion: Perineal body; anococcygeal body; walls of prostate,
vagina, rectum, and anal canal.
Nerve supply:
1. Nerve to levator ani (S4)
2. Pudendal nerve
Action:
Help to support the pelvic viscera; acting together they raise
the pelvic floor and assist the abdominal muscles in forced
expiration activities.

12. Levator Ani Muscle
Three parts
1. Pubococcygeus
2. Puborectalis
3. Iliococcygeus

13. Coccygeus Muscle
Origin:
Ischium spine
Insertion:
Lower end of the sacrum and coccyx
Nerve supply:
Branches of S4 and S5
Action:
Forms a small part of the pelvic diaphragm
that supports the pelvic viscera, flexes the
coccyx.

14. Coccygeus Muscle

15. Branches to the lower limb that leave the pelvis
through the greater sciatic foramen:
1. The Sciatic nerve.
2. The Superior gluteal nerve.
3. The Inferior gluteal nerve.
4. The Nerve to the quadratus femoris muscle.
5. The Nerve to the obturator internus muscle.
6. The Posterior cutaneous nerve of the thigh.

16. Branches to the pelvic muscles, pelvic
viscera, and perineum:
1. The Pudendal nerve.
2. The Nerves to the periformis muscle.
3. The Pelvic splanchnic nerve.

17. Arteries of the Pelvis
• Common Iliac Artery:
External iliac:
Travels lateral to superior pubic ramus.
Branches:
Deep circumflex iliac artery.
Inferior epigastric artery:
Travels deep to inguinal ligament.
Becomes femoral artery.

19. Arteries of the True Pelvis
The following arteries enter the pelvic cavity:
o Internal iliac artery
o Superior rectal artery
o Ovarian artery
o Median artery

20. Arteries of the Pelvis
• Common Iliac Artery:
Internal iliac:
Travels inferiorly and medially over pelvic brim.
Supplies:
Pelvic organs.
Gluteal muscles.
Perineum.
Two divisions:
Anterior.
Posterior.

21. Internal Iliac Arteries
Branches of the Anterior Division:
Umbilical artey
Obturator artery
Inferior artery
Middle rectal artery
Internal pudendal artery
Inferior gluteal artery
Uterine artery
Vaginal artery

22. Internal Iliac Arteries
• Anterior division:
Umbilical artery:
Gives off superior vesicle arteries:
Supplies superior aspect of urinary
bladder.
Becomes either:
Obliterated umbilical artery.
Medial umbilical artery.

23. Internal Iliac Arteries
• Anterior division:
Obturator artery:
Travels anteriorly and inferiorly along pelvic
wall.
Exits pelvic cavity through:
Obturator canal (in obturator foramen).
Supplies:
Pelvic muscles.
Ilium.
Femoral head.
Muscles of medial thigh.

24. Internal Iliac Arteries
• Anterior division:
Inferior vesicle artery (male):
Travels inferiorly and posteriorly to urinary
bladder.
Analogous to female uterine artery.
Prostatic branch:
Supplies prostate gland.
Artery to ductus deferens.

25. Internal Iliac Arteries
• Anterior division:
Middle rectal artery:
Travels inferior to lower rectum.
Supplies lower rectum and seminal vesicles
in males.

26. Internal Iliac Arteries
• Anterior division:
Internal pudendal artery (male):
Exits pelvic cavity through greater sciatic
foramen.
Loops around ischial spine.
Enters perineum through lesser sciatic
foramen.
Enters pudendal canal.

27. Internal Iliac Arteries
• Anterior division:
Internal pudendal artery (male):
Branches:
Inferior rectal.
Perineal artery:
Posterior scrotal artery.
Artery of bulb of penis.
Deep artery of penis.
Dorsal artery of penis.

28. Internal Iliac Arteries
• Anterior division:
Internal pudendal artery (female):
Branches:
Inferior rectal.
Perineal artery:
Posterior labial artery.
Artery of vestibule of vagina.
Deep artery of clitoris.
Dorsal artery of clitoris.

29. Internal Iliac Arteries
• Anterior division:
Inferior gluteal artery:
Exits pelvic cavity through greater sciatic
foramen.
Usually passes inferior to piriformis muscle.
Supplies:
Coccygeus muscle.
Three levator ani muscles.
Piriformis and quadratus femoris muscles.
Uppermost posterior thigh muscles.
Gluteus maximus.
Sciatic nerve.

30. Internal Iliac Arteries
• Anterior division:
Uterine artery (female):
Travels medially in broad ligament.
Analogous to male inferior vesicle artery.
Supplies uterus and vagina.

31. Internal Iliac Arteries
• Anterior division:
Vaginal artery :
This artery usually takes the place of the
inferior vesical artery present in the male.
It supplies the vagina and the base of the bladder.

32. Internal Iliac Arteries
Branches of the Posterior Division:
Iliolumbar artery
Lateral sacral artery
Superior gluteal artery

33. Internal Iliac Arteries
• Posterior division:
Iliolumbar artery:
Travels posterior to sacroiliac joint posterior
to common iliac vessels and psoas major
muscle.
Supplies:
Psoas major muscle.
Iliacus muscle.
Quadratus lumborum muscle.
Cauda equina (in vertebral canal).

34. Internal Iliac Arteries
• Posterior division:
Lateral sacral artery:
Travels on anteromedial aspect of piriformis
muscle.
Sends branches to ventral sacral foramina.
Supplies:
Piriformis muscle.
Sacral canal structures.
Erector spinae muscles.

35. Internal Iliac Arteries
• Posterior division:
Superior gluteal artery:
Exits pelvic cavity through greater sciatic
foramen superior to piriformis muscle.
Supplies:
Piriformis muscle.
Gluteus medius muscle.
Gluteus minimus muscle.
Tensor fascia latae muscle.

36. Lymphatics of the Pelvies
• External Iliac Nodes
• Internal Iliac Nodes
• Common Iliac Nodes
Veins of the pelvis
• External Iliac Vein
• Internal Iliac Vein
• Median Sacral Veins

37.  Sacroiliac Joints:
Synovial joints formed between the sacrum and the iliac
bones. The strong posterior and interosseous
sacroiliac ligaments suspend the sacrum between the
two iliac bones.
Movements
A small but limited amount of movement is possible at these
joints.
Nerve Supply
The nerve supply is from branches of the sacral spinal
nerves.
Joints of the pelvis

39.  Symphysis Pubis:
The symphysis pubis is a cartilaginous joint between the
two pubic bones. The joint is surrounded by ligaments that
extend from one pubic bone to the other.
Movements
Almost no movement is possible at this joint.
 Sacrococcygeal Joint:
The sacrococcygeal joint is a cartilaginous joint between
the bodies of the last sacral vertebra and the first
coccygeal vertebra. The sacrum and coccyx are joined by
ligaments.
Movements
Extensive flexion and extension are possible at this joint.

40. Sex Differences of the Pelvis
The more obvious differences result from the adaptation of the female
pelvis for childbearing. The storanger muscles in the male are
responsible for the thicker bones and more prominent bony markings.
I. The false pelvis is shallow in the female and deep in the male.
II. The pelvic inlet is transversely oval in the female but heart shaped in the
male because of the indentation produced by the promontory of the
sacrum in the male.
III. The pelvic cavity is roomier in the female than in the male, and the
distance between the inlet and outlet is much shorter.
IV. The pelvic outlet is larger In the female than in the male. In the female the
ischial tuberosities are everted and in the male they are turned in.
V. The sacrum is shorter, wider, and flatter in the female than in the male.
VI. The subpubic angle, or pubic arch, is more rounded and wider in the
female than in the male.

41. Surface Anatomy
Surface Landmarks
Iliac Crest
Anterior Superior Iliac Spine
Posterior Superior Iliac Spine
Pubic Tubercle
Pubic Crest
Symphysis Pubis
Spinous Processes of Sacrum
Sacral Hiatus
Coccyx

42. Anterior view of the pelvis of a 27-year-old man. Anterior view of the pelvis of a 29-year-old woman.

43. Viscera
Urinary Bladder
In adults, the empty bladder is a pelvic organ and lies
posterior to the symphysis pubis. As the bladder fills, it
rises up out of the pelvis into the abdomen, where it can
be palpated through the anterior abdominal wall above
the symphysis pubis.
In children, unit the age of 6 years, the bladder is an
abdominal organ even when empty because the capacity
of the pelvic cavity is not great enough to contain it. The
neck of the bladder lies just below the level of the upper
border of the symphysis pubis.

44. Viscera
Uterus
Toward the end of the 2nd month of pregnancy, the
fundus of the uterus can be palpated through the
lower part of the anterior abdominal wall. With the
progressive enlargement of the uterus, the fundus
rises above the level of the umbilicus and reaches
the region of the xiphoid process by the 9th month of
pregnancy. Later, when the presenting part of the
fetus, usually the head, descends into the pelvis, the
fundus of the uterus also descends.

45. Viscera
Rectal and Vaginal Examinations as a Means of
Palpating the Pelvic Viscera
Bimanual rectoabdominal and vaginal–abdominal
examinations are extremely valuable methods of
palpating the pelvic viscera.

46. A: Surface anatomy of the empty bladder and the full bladder.
B: Height of the fundus of the uterus at various months of pregnancy.