Download Pelvis + Perineum

Pelvis + Perineum
Pelvic Cavity
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Enclosed by bony, ligamentous and
muscular wall
Contains the urinary bladder, ureters,
pelvic genital organs, rectum, blood
vessels, lymphatics and nerves
Pelvic inlet (superior pelvic aperture)
Pelvic outlet (inferior pelvic aperture)
Superior Apeture
Inferior Pelvic Border
Lesser Pelvis ( pelvis minor)
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Location of pelvic viscera – the urinary
bladder and reproductive organs such as
the uterus and ovaries
Bounded by the pelvic surfaces of the
hip bones, sacrum, and coccyx
Limited inferiorly by the musculofascial
pelvic diaphragm
AKA True Pelvis
Pelvic Walls and Floors
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Anterior pelvic wall – is 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 (O: proximal surface of the ilium
and ischium; obturator membrane I:
greater trochanter of the femur)
Anterior Pelvic Wall
Pelvic Walls and Floor
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Posterior Pelvic Wall – formed by the
sacrum and coccyx, adjacent parts of the
ilia, and the S-I joints; piriformis muscle
covers the area (O: pelvic surface of 2nd
and 4th sacral segments, superior margin
of the greater sciatic notch and
sacrotuberous ligament, I: greator
trochanter of femur)
Posterior Pelvic Wall
Posterior Pelvic Wall
Pelvic Floor
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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
Pelvic Diaphragm
Pelvic Floor - Male
Pelvic Floor - Female
Levator Ani
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Consists of three parts – the pubococcygeus, the
puborectalis and the iliococcygeus.
Collectively they run from the body of the pubis, the
tendinous arch of the obturator fascia and the ischial
spine TO the perineal body, the coccyx, the anococcygeal
ligament, the walls of the prostate or vagina, the rectum
and the anal canal
Innervated by the nerve to levator ani from S4 and the
inferior anal (rectal) nerve (from S2-S4) and the
coccygeal plexus
Help to support the pelvic viscera; acting together they
raise the pelvic floor and assist the abdominal muscles in
forced expiration activities
Perineal Body
Coccygeus Muscle
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O: ischial spine, I: inferior end of the
sacrum, I: branches of S4 and S5
Forms a small part of the pelvic
diaphragm that supports the pelvic
viscera, flexes the coccyx
Viscera
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Urinary organs in the pelvis
Ureters – muscular (smooth) tubes
running from kidneys to bladder 25 to 30
cm long
Bladder – a hollow container surrounded
by a strong smooth muscular wall
Temporary reservoir for urine
Apex, Body, Fundus, Neck, Uvula
Pelvic Viscera - Female
Uterus
Perineum
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Lies inferior to the pelvic outlet and is
separated from the pelvic cavity by the
pelvic diaphragm (Levator ani and
coccygeus muscles)
Bounded by Pubic symphysis anteriorly;
inferior pubic rami and ischial rami
anterolaterally; ischial tuberosity
laterally; sacrotuberous ligament
posterolaterally; inferiorly by sacrum and
coccyx
Perineum
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Two Triangles
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Anal triangle (posterior) contains the anus
Urogenital triangle (anterior) contains the root of the
scrotum and penis in males or the external genitalia in
females
The perineal membrane stretches between the
two sides of the pubic arch and covers the
anterior part of the outlet
The perineal body is an irregular fibromuscular
mass located between the anal canal and the
perineal membrane
Triangles
Perineal Body
Perineal Membrane
Perineum-Female
Perineum - Male
Perineum
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Muscles
Bulbospongiosus – F O: central tendon of
perineum, M O: central tendon of perineum
and bulb of penis; F I: dorsum of clitoris,
urogenital diaphragm, M I: root of penis; A:
compress vagina orifice or compress urethra,
N: perineal nerve, pudenal nerve
Ischiocavernosus – O: ramus of ischium, I:
near pubic symphysis, maintains erection of
penis or clitoris
Muscles - Female
Muscles - Female
Muscles – Male
Muscles - Male
Perineum
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Muscles
External anal sphincter (skeletal muscle)
– O: skin an fascia surrounding anus and
coccyx, I: perineal body, A: closes anal
canal, N: Inferior Anal Nerve (Somatic
nerve from S2-S4) – inhibits voiding
Internal Anal Sphincter – smooth muscle
innervated by sympathetic NS
(S2,S3,S4) – inhibits voiding
External/Internal Anal Sphincter
Superficial Transverse Perineal
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O: Ischial tuberosity
I: Perineal body
A: Support perineal body
N: Pudenal nerve
External Urethral Sphincter
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O: Ischial tuberosity
I: surround urethra
A: compress urethra to maintain urine
continence
N: Pudenal (S2-S4)
Superficial Transverse Perineal F
Superficial Transverse Perineal F
Superficial Transverse Perineal M
Deep Transverse Perineal
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O: Medial Aspect of Ischial Ramus
I: Pineal Body
A: Stabilizes position of the perineal
body
N: Pudenal N (S2-S4)
Deep Transverse Perineal - F
Deep Transverse Perineal -F
Deep Transverse Perineal - M
Deep Transverse Perineal M
Ischianal fossa - male
Pudendal canal
Pudendal canal & content
Peritoneum
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Continuous with peritoneum of abdomen
Drapes over pelvic viscera in the midline
to form:
Pouches
Folds between viscera and pelvic walls
Pouches protect viscera from rectum
Male Peritoneum