Download Muscles and Fascia of Pelvic Wall

Muscles and Fascia of
Pelvic Wall
Dr. Sama-ul-Haque
Objectives

Describe the origin, insertion, nerve supply and
actions of the Piriformis, obturator internus &
levator ani.

Describe the pelvic fascia organization.
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
Nerve supply:
N to Obturator internus ( L5, S1, S2)

Action:
Lateral Rotation of the thigh

Obturator Internus Muscle
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
Piriformis Muscle
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.
Levator Ani

Three parts
1. Pubococcygeus
2. Puborectalis
3. 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
Levator Ani

Nerve supply:
1.
Nerve to levator ani (S4)
2.
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.
Pelvic Walls
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.

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.

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).

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

Pelvic Diaphragm
Pelvic Floor (Male)
Pelvic Floor (Female)
Female Pelvic Floor (Medial view)
Perineal Body
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.
Pelvic Fascia
1- Membranous pelvic fascia:
Parietal and visceral
 2- Endopelvic fascia:
Loose and condensed

Pelvic Fascia
Thank you