1. Muscles and Fascia of Pelvic Wall
Dr. Sama-ul-Haque

2. Objectives
Describe the origin, insertion, nerve supply and actions of the Piriformis, obturator internus & levator ani.
Describe the pelvic fascia organization.

3. 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 1- the hip bones and the
2-Obturatorinternus muscles:
Origin: Proximal surface of the ilium & ischium;
obturator membrane
Insertion: Greater trochanter of the femur

4. Nerve supply:
N to Obturator internus ( L5, S1, S2)
Action:
Lateral Rotation of the thigh

5. 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

8. Piriformis Muscle

9. Pelvic Floor Formed by the funnel shaped 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.

10. Levator Ani Three parts Pubococcygeus Puborectalis Iliococcygeus
Origin:
Collectively they run from the body of the
pubis, the tendinous arch of the obturator
fascia and the Ischial spine.
Insertion: To the perineal body, the coccyx, the anococcygeal ligament, the walls of the prostate or vagina, the rectum and the anal canal

11. Levator Ani Nerve supply: Nerve to levator ani (S4) Pudendal nerve
Action:
1- Forms most of the pelvic diaphragm that helps to support the pelvic viscera;
2- Acting together they raise the pelvic floor and 3- Assist the abdominal muscles in forced expiration activities.

12. Pelvic Walls

13. The anteroinferior pelvic wall:
Is formed primarily by the bodies and rami of the pubic bones and the pubic symphysis.
Participates in bearing the weight of the urinary bladder.

15. The lateral pelvic walls:
Have a bony framework formed by the hip bones, including the obturator foramen ; the obturator foramen is closed by the obturator membrane .
Are covered and padded by the obturator internus muscles .Each obturator internus passes posteriorly from its origin within the lesser pelvis, exits through the lesser sciatic foramen, and turns sharply laterally to attach to the femur.

16. The medial surfaces of these muscles are covered by obturator fascia, thickened centrally as a tendinous arch that provides attachment for the pelvic diaphragm
Have the obturator nerves and vessels and other branches of the internal iliac vessels located on their medial aspects (medial to obturator internus muscles).

17. The posterior pelvic wall:
Consists of a bony wall and roof in the midline (formed by the sacrum and coccyx) and musculoligamentous posterolateral walls (formed by the sacroiliac joints and their associated ligaments and piriformis muscles).
Each piriformis muscle leaves the lesser pelvis through the greater sciatic foramen to attach to the femur .
Is the site of the nerves forming the sacral plexus; the piriformis muscles form a muscular bed for this nerve network

18. Pelvic Diaphragm

19. Pelvic Floor (Male)

20. Pelvic Floor (Female)

21. Female Pelvic Floor (Medial view)

22. Perineal Body

23. Coccygeus Muscle Origin: Ischial 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.

24. Pelvic Fascia

25. 1- Membranous pelvic fascia:
Parietal and visceral
2- Endopelvic fascia:
Loose and condensed

26. Pelvic Fascia

27. Thank you