Pelvis And Perineum

Front 1

pelvis

Back 1

Literally means “basin”
 Part of the trunk inferoposterior to the abdomen; transition from the trunk to the lower extremities
 Extends from the pelvic inlet to the pelvic outlet
 Walls: bony, muscular, ligamentous
 Functions:
o Transmits the weight of the body from the vertebral column to the femurs
o Supports and protects pelvic viscera
o Provides muscle attachment
o Absorbs stress
o Functions as passage during child birth
o Protects the distal portion of the GIT and urinary tract and internal genital organs

Front 2

pelvic brim/inlet and boundaries

Back 2

Serves as the boundary between True/lesser/minor pelvis and the false/greater/major pelvis
 Boundaries:
o Anterior – Symphysis pubis
o Posterior – Anterior margin of sacral promontory
o Lateral – Iliopectineal line or linea terminalis

Front 3

false pelvis

Back 3

Of little clinical/obstetric importance
 Varies in size – flare of iliac bones; location of some abdominal viscera such as the sigmoid colon and some loops of ileum
 Boundaries:
o Anterior: lower part of the anterior abdominal wall
o Posterior: lumbar vertebrae
o Lateral: iliac fossae and iliacus muscle
 Supports lower abdominal viscera and after 3 months of pregnancy and during labor, it directs the fetal head to the true pelvis

Front 4

articulation/orientation pelvic bones

Back 4

Articulations:
1. Anterior: Two hip bones at the symphysis pubis
2. Posterior: Hip bones with the sacrum at the sacroiliac joints
Orientation of the Pelvis
The front of the symphysis pubis and the anterior superior iliac spines should lie in the same vertical plane
Pelvic surface of the symphysis pubis faces upward and backward and the anterior surface of the sacrum is directed forward and downward

Front 5

hip bones

Back 5

 Forms most of the bony pelvis (pelvic girdle)
 Comprise the anterior and lateral walls of pelvis
 United in front: symphysis pubis
 Behind: joined to sacrum at sarcoiliac joint
 Formed of 3 separate bones fused after puberty by cartilage at the area of acetabulum

Front 6

illium

Back 6

– Superior portion of hip bone; fan-shaped
Iliac crest
 Ala of the ilium (represents the spread of the fan)
 4-5cm posterior to ASIS
 Extends from anterior and posterior superior iliac spines
 Corresponds to L5 (iliac tubercle) while the highest point lies at L4
 Landmark for anesthesia, regional anesthesia, lumbar or spinal tap, extends from ASIS to PSIS
Body of ilium
 Handle of the fan
 Forms the superior part of the acetabulum
Iliac fossa
 Formed by the anterior concave part of the ala
 Where iliacus muscle attaches
Auricular surface
 Attaches to the sacrum at sacroiliac joint
Pectineal line
 Forms the inner aspect margin of superior ramus of the pubis
Iliopectineal line/Linea terminalis
 Composed of arcuate line and pectineal line

Front 7

ischium

Back 7

Forms the posterior and inferior portion of hip bone
Body of ischium
 Forms the posterior part of the acetabulum
Ramus
 Forms part of the inferior boundary of the obturator foramen
Ischial tuberosity
 Large posteroinferior protuberance of the ischium
Ischial spine
 Small pointed posterior projection near the junction of the ramus and body

Front 8

pubis

Back 8

Anterior
Superior pubic ramus
 Forms the anterior part of the acetabulum
 Has an oblique ridge called pectin pubis on its superior aspect
Inferior pubic ramus
 Forms part of the inferior boundary of the obturator foramen
Pubic crest
 Thickening on the anterior part of the body of pubis
 Prominence at the medial aspect
 Terminates laterally to a bigger tubercle becoming pubic tubercle
Pubic tubercle
 Superiorly and laterally forms an edge called pecten pubis or pectineal line
Ischiopubic ramus
 Formed by union of inferior ramus with ischial ramus
Subpubic angle
 Seen in the inferior

Front 9

sacrum

Back 9

Single wedge-shaped bone with 5 rudimentary
 vertebrae fused together
 Attachments:
o Above – attached to the 5th lumbar vertebrae
o Below – 1st coccygeal vertebrae
o Lateral – Ilium (via sacroiliac joint)

Front 10

sacral promontory

Back 10

formed by anterior margin of the first sacral vertebra and forms the posterior boundary of the pelvic inlet
o Important obstetric landmark used for measuring the size of pelvis

Front 11

sacral canal

Back 11

o Anterior and posterior root of lumbar nerves
o Sacral and coccygeal nerves which forms the lower part of the cauda equine
o Filum terminale
o Meninges (which extends up to lower border of 2nd sacral vertebra only)
o Fibrofatty material

Front 12

vertebral foramina

Back 12

Lamina of 5th and sometimes that of the 4th fail to fuse in the midline forming the sacral hiatus (area where spinal needle can be injected when giving caudal anesthesia – anesthetizing area of perineum and lower part of hypogastrium)
 Four openings on each side

Front 13

lumbosacral angle

Back 13

: angle form between 5th lumbar vertebrae and sac

Front 14

coccyx

Back 14

 Triangular bone
 4 coccygeal vertebrae fused together
 Contains body, no pedicle
 1st coccyx – Only coccygeal vertebra, containing rudimentary transverse process, has cornua (on dorsal surface) representing the pedicle and superior articular surfaces

Front 15

pelvic diaphragm

Back 15

Primarily supports the pelvic viscera
 Stretches across the pelvis and divides it into:
o Pelvic cavity – above; contains pelvic viscera
o Perineum – below; contains external genitalia and pouches
 Formed by the Levatores ani muscles and the Coccygeus muscle and the inferior and superior fascia that covers the two muscles (extensions of parietal pelvic fascia)
 It is incomplete anteriorly for passage of urethra in males and urethra and vagina in females (Urogenital Hiatus)
 floor/inferior wall of the pelvic cavity

Front 16

levator ani ms origin, action, nerve

Back 16

 Wide, thin sheet
Origin:
Body of pubis, tendinous arch (formed by thickening of fascia covering the obturator internus muscle) and ischial spine
Action:
Efficient muscular sling that supports pelvic viscera, resist rise in intrapelvic pressure, and exerts sphincteric action at the vagina and anorectal junction
Nerve Supply:
4th sacral nerve and pudendal nerve

Front 17

ligaments pelvis

Back 17

Sacrotuberous ligament – arises from ischial spine and attaches to the lateral portion of the sacrum and coccyx and PIIS
 Sacrospinous ligament – attaches to ischial spines and arises to the lateral portion of the sacrum and coccyx
 These two prevent the lower end of sacrum and coccyx from being rotated upward at sacroiliac joint by the weight of the body.
 Convert the two sciatic notches into foramen
 Normally, Greater foramen is where the vessels and nerves EXITS from true pelvis to gluteal area, while Lesser foramen is where vessels and nerves ENTERS from gluteal area to true pelvis.
 Obturator foramen
 Closed by obturator membrane except in the canal

Front 18

ant. insertions levator ani

Back 18

Levator prostate or sphincter vaginae
 Surround and form a sling around the prostate gland or vagina
 As the name implies, it supports the prostate or constricts the vagina
 Insert into the perineal body (mass of fibrous tissue between lower half of vagina and anal canal or between the base of penis and anal canal)
 Imaginary line between two distal tuberosities; the central point corresponds to the area of perineal body (underneath the skin of the central point)
 In males, known as the central point/tendon of perineum
 Serve as attachment sites for
 Levator ani muscle
 Superficial transverse perineal ms
 Deep transverse perineal ms
 External anal sphincter
 Vulvocavernous/vulvosphongiosus

Front 19

intermedate fibers levator ani insertions

Back 19

Puborectalis forms a sling around rectum and anal canal
 Its major role is maintaining fecal continence
 Pubococcygeus is formed by the more posterior fibers of intermediate fibers
 Goes posterior to puborectalis ms and inserts into anococcygeal body (mass of fibrous tissue between tip of coccygeus and anus)

Front 20

post fibers insertion levator ani

Back 20

Iliococcygeus into anococcygeal body and coccyx

Front 21

visceral pelvic fascia

Back 21

Covers pelvic viscera
 Supports all pelvic viscera
 Fuses with parietal layer when viscus contacts pelvic wall
 Thickens to form fascial ligaments which extend from pelvic wall to viscera
 Named according to their attachments (thickenings)
 Examples:
1. Pubovesical ligaments – Attaches the posterior portion of the pubic bone to the length of urinary bladder
2. Puboprostatic ligament – Supports prostatic glands
3. Pubocervical ligament – Supports cervix
4. Transverse cervical ligament – Cardinal
5. Uterosacral/Sacrocervical ligament – From cervix to sacrum
 In female, fascial ligaments of uterine cervix assist with support of uterus prevent prolapse
 Parametrium: connective tissue around uterine cervix and vagina

Front 22

pelvic peritoneum

Back 22

Continuation of abdominal peritoneum
o Parietal Peritoneum – Line walls of peritoneal cavity
o Visceral Peritoneum
o Peritoneal cavity falls short of pelvic cavity
o Partially covers pelvic viscera (which lies below peritoneum)
o Endopelvic Fascia – Viscera embedded in abundant extraperitoneal connective tissue

Front 23

male pelvic peritoneum

Back 23

 From the anterior abdominal wall, parietal pelvic peritoneum reflects onto the anterior fundal and posterior surfaces of the urinary bladder  Goes down and covers the superior surface of seminal vesicle  Goes up to cover anterior and lateral portion of rectum up to its mid portion.
 As the peritoneum reflects between the urinary bladder and the rectum, it forms rectovesical pouch
 Anterior abdominal wall >> Superior of bladder >> Descends over fundus (when collapsed)
 Distended bladder: Abdominal organ; paravesical fossae
 Peritoneum posterior to bladder curves onto rectum (elevation over seminal vesicle)
 Rectovesical pouch – Most dependent portion of pelvic cavity in standing position

Front 24

ureteric fold

Back 24

o It is homolog to broad ligament of the female
o Peritoneal fold is formed when the peritoneum passes up and over ureter and vas deferens on each side of the bladder separating paravesical fossa and pararecta fossa.

Front 25

parietal pelvic fascia

Back 25

Lines the walls of pelvis
 Named according to muscle it overlies
 Continuation of transversalis fascia (from anterior abdominal wall) and iliopsoas fascia (posterior abdominal wall)
 Likewise continuation of superior fascia of urogenital diaphragm
 Thickens at the area of obturator internus and levator ani ms to form tendinous arch of the levator ani muscle (only thickening)
 Pelvic diaphragm deficient: continuous with inferior surface of pelvic diaphragm in perineum
 Fuses with periosteum when in contact with bone
 In perineum: forms the superior fascial layer of urogenital diaphragm
o Superior to inferior:
From pelvic cavity  Pelvic diaphragm  Urogenital diaphragm  Superficial perineal pouch  Perineum
 Structure that divides the perineum from the pelvic cavity is the Levator ani muscle

Front 26

pelvic fascia

Back 26

 Formed of loose connective tissue below the peritoneum
 Below, continuous with fascia of perineum
 Continuation of fascia lining abdominal walls
 Continuous with endoabdominal fascia (Snell)
 The connective tissue that fills the space between the parietal pelvic fascia and the visceral pelvic fascia (Moore)
 Divided into:
A. Parietal pelvic fascia (wall covering)
B. Visceral layer of the pelvic fascia (covering and support of blood vessels, nerves and lymphatic drainage)

Front 27

coccygeus ms nerve and action

Back 27

SECTION B UERMMMC Class 2014 ANATOMY 4 | 13
 Arise from Ischial spine
 Inserted into the sacrum and the coccyx
 Located posterior to the levator ani muscle
Action:
Assist Levatores ani in supporting the pelvic viscera
Nerve supply:
A branch of the fourth and fifth sacral nerves

Front 28

pelvic peritoneum female

Back 28

Once the peritoneum reaches the area of the isthmus, it goes up to cover the vesical, fundal, and intestinal surfaces of the uterus  Goes down to cover the posterior fornix  Goes up again to cover the anterior and inferior lateral wall of the rectum up to its mid portion and back to the posterior abdominal wall
 Peritoneum from posterior bladder turns to uterus (isthmus) >> Covers vesical fundal, intestinal surface >> 1-2 cm posterior fornix of vagina >> Rectum
 As the pelvic peritoneum reflects the walls and pelvic viscera, it forms 2 pouches:

Front 29

rectouterine pouch of douglas

Back 29

Between uterus and posterior fornix and rectum
 Where most of fluid accumulate (pelvic abscesses, blood, etc.)
 Most dependent portion of pelvic cavity in standing position

Front 30

broad ligament

Back 30

2 layers of peritoneum covering 2 surfaces of uterus come together at margins and extend laterally
Enclosed in free upper edge is a uterine tube

Front 31

round ligament

Back 31

Under anterior leaf
Attached to side of uterus
Often stretched during pregnancy

Front 32

ovarian lig

Back 32

Attached to side of uterus and laterally to ovary
Remnant of the upper part of the gubernaculums

Front 33

mesovarium

Back 33

Posterior extension of peritoneum of ovarian ligament

Front 34

supspensory lig ovary

Back 34

encloses ovarian vessels

Front 35

mesoalphinx

Back 35

sup to mesovarium

Front 36

true pelvis/lesser

Back 36

Significant in obstetrics
 Shape and dimension of the female pelvis is of great Importance for obstetrics as it serves as the birth canal
 Extends from pelvic inlet to the pelvic outlet

Front 37

pelvic inlet/brim/linea terminalis

Back 37

Divides the pelvis into two: False Pelvis(superior) and True Pelvis (inferior)
Formed by the sacral promontory (posteriorly), iliopectineal line (laterally), and symphysis pubis (anteriorly)
Iliopectineal line = Arcuate line + Pectineal line

Front 38

pelvis outlet

Back 38

Closed by the pelvic diaphragm
Bounded posteriorly by the tip of coccyx, laterally by the ischial tuberosities, and anteriorly by the pubic arch between the ischiopubic rami

Front 39

pelvic cavity

Back 39

Pelvic Cavity
Lies between the inlet and the outlet
A short, curved canal with a shallow anterior wall and a much deeper posterior wall
Covered by the parietal pelvic peritoneum

Front 40

imaginary planes/diameters

Back 40

A. Plane of Pelvic Inlet
B. Plane of Midpelvis
C. Plane of Pelvic Outlet
D. Greatest pelvic dimension (no obstetrical significance)

Front 41

obstetric conjugate

Back 41

10.5cm
Distance between the sacral promontory to the midline between the superior margin and lower border of symphysis pubis
 Equal to DC minus 1.5 or 2 cms
 Narrowest AP diameter
 It is measured to assess the adequacy of the pelvic inlet (important in childbirth)

Front 42

diagonal conjugate

Back 42

 Around 11.5 cm
 Distance between the sacral promontory to lower border of the symphysis pubis
 Can be measured clinically

Front 43

true conjugate

Back 43

Distance measured between anterior margin of sacral promontory and the superior margin of the symphysis pubis

Front 44

pelvic inlet/brim diameteres

Back 44

A-P diameter (conjugate)
- 3 conjugate diameters arise from superior anterior margin of sacral promontory

Front 45

clinical pelvimetry

Back 45

Done during the latter part of pregnancy, when pelvic ligaments are soft already.
 Use index and middle fingers when measuring diagonal conjugate. Insert the examining fingers, try to palpate for sacral promontory using index finger (measure the distance from that portion to the area of knuckle when it touches the inferior border of the symphysis pubis). You will get the measurement of diagonal conjugate, then deduct 1.5cm from it to get the measurement of obstetric diameter.
 For an inlet to be adequate, you should not feel for the sacral promontory very easily, must exert an effort to palpate. If the sacral promontory is inaccessible, then the obstetric conjugate is more than 10.5cm.

Front 46

transverse diametere

Back 46

Greatest distance between the iliopectineal lines
Cannot be measured clinically
Measured by x-ray pelvimetry
13.5 cm

Front 47

oblique diameter

Back 47

Measure from R/L sacroiliac to the opposite iliopectineal eminence
Could be R/L oblique diameter based on the location of sacroiliac
13 cm

Front 48

pos. sagittal diameter

Back 48

Around 4cm

Front 49

midpelvis diameter/planes

Back 49

Measured at the level of the ischial spines
Important in engagement of fetal head in cases of obstructive labor
interspinous, ap diameter, post sag

Front 50

interspinous diameter

Back 50

10 cms or more; narrowest transverse of all pelvic diameter
Smallest and narrowest pelvic diameter
Distance between two ischial spines

Front 51

engagement

Back 51

 Important when assessing whether the fetal head is engaged or not. Most dependent portion of the head reaches the ischial spine or below the level of the ischial spines  head of baby is engaged already.
 Engaged when biparietal diameter of the fetal head should have gone down to the pelvic inlet (adequate of head of baby is engaged)

Front 52

midpelvis diameter ap/post sag dia

Back 52

A-P diameter
11.5 cms
Not assessed clinically
Measured only by x-ray pelvimetry
Measured at the level of Ischial spines
3. Posterior sagittal diameter
4.5cm

Front 53

pelvic outlet/diameters /planes

Back 53

A-P diameter
9.5-11.5 cms
Lower border of the symphysis pubis to the tip of coccyx
2. Transverse diameter
11 cm
Between inner edge of ischial tuberosities (closed fist inserted in between tuberosities)
3. Posterior Sagittal diameter
Tip of coccyx where AP diamter bisects transverse diameter should be more than 7.5 cm (tip of coccyx to right angle intersection with a line between the ischial tuberosities)

Front 54

measurement transverse diameter

Back 54

Place closed fist against the perineum between the two ischial tuberosities. The distance across the top of a closed fist can be used as a frame of reference to estimate the distance between the ischial tuberosities. If more than 8cm, chances are pelvic inlet is adequate.
 Pelvic inlet,

Front 55

pelvic axis

Back 55

Imaginary line joining the central points of AP diameters from the inlet to the outlet
1. Midline of obstetric conjugate
2. AP diameter of midpelvis
3. AP diameter of pelvic outlet
 It is the curved course taken by babies head during parturition.

Front 56

clinical pelvimetry-adequacy assessment

Back 56

A. Pelvic inlet – Sacral promontory not easily accessible
B. Midpelvis
a. Palpate ischial spines, if quite prominent  Should be measured
b. Should be around 10cm or more.
c. Sidewalls should be parallel
d. Concavity of the sacrum should be deep not shallow.
C. Pelvic outlet
a. Bi-ischial diameter >8cm (closed fist)
b. Shape of subpubic arch wider (expected among female pelvis) not angular/acute

Front 57

platypelloid

Back 57

- Rare, 5% of individuals
(flattened gynecoid)
- Transverse diameter is
longer than AP diameter
- Between gynecoid and
android pelvis

Front 58

gynecoid

Back 58

Seen among most
females
- Anterior segment –
More rounded
- Posterior segment –
Roomier

Front 59

anthropoid

Back 59

Inlet is oval (more
rounded)
- AP diameter is longer
than transverse
diameter

Front 60

android

Back 60

- Typical male pelvis
- Inlet is heart shaped
- AP diameter equals
transverse diameter
- Posterior segment: Less
roomier
- Anterior segment: Triangular

Front 61

differences b/w males female pelvis

Back 61

false pelvis: m-deep, f-shallow
pelvic inlet: m-heart, f- oval
p. cavity: f- roomier
p. oulet: m-smaller, f- larger
ischial tuberosity: m-inverted, f-everted
sacrum: f-shorter, wider, fatter
pubic arch: m-acute, angular, f-rounder, wider

Front 62

post pelvic wall

Back 62

Extensive and formed by the sacrum and coccyx with piriformis muscle
Piriformis Muscle – Arises from the front of the lateral mass of the sacrum and leaves the pelvis to enter the gluteal region by passing laterally throught he greater sciatic foramen
Action
 Lateral rotator of the femur at the hip joint
Nerve Supply
 Receives branches from the sacral plexus
Insertion
 Upper border of the greater trochanter of the femur

Front 63

ant. pelvic wall

Back 63

Shallowest wall and formed by the bodies of the pubic bones, the pubic rami, and the symphysis pubis

Front 64

lat pelvic wall

Back 64

Formed by part of the hip bone below the pelvic inlet, the obturator membrane, the sacrotuberous and sacrospinous ligaments, and the obturator internus muscle and its covering fascia

Front 65

inf pelvic wall/floor

Back 65

The floor of the pelvis supports the pelvic viscera and is formed by the pelvic diaphragm
It divides the main pelvic cavity (superior) and perineum (inferior)

Front 66

weak areas pelvis

Back 66

Pubic rami
2. Acetabulum (areas immediately surrounding)
3. Region of sacroiliac joint
4. Ala of ilium

Front 67

pelvic structures in male vs female

Back 67

both: pelvic colon, rctum, terminal coils ileum, bladder

f-ureter, m-ureter subperitoneal
f-uterus, m- seminal vesciles
f-ovaries, m-prostate gland
f-uterine tube, m- denon villers fascia
f-up 1/2 vag, m-ductus deferens, ejactulatory duct

Front 68

anal triangle boundaries, nerve, lymph

Back 68

Boundaries:
Anterior: Perineal body, area of the fascia of the anterior triangle fuse with each other
Laterally: Sacrotuberous ligament and ischial tuberosity
Midline: Anus; on each side  Ischiorectal fossa
Posterior: Coccyx
Nerve supply: Inferior rectal nerve branch of internal pudendal nerve
Lymphatic drainage: medial group sup ingunal group nodes

Front 69

urogenital triangle

Back 69

Urogenital triangle
- Anterior Triangle
- Contains the Urogenital Orifice
- Females: Contain external genitalia/vulva and orifices of vagina and urethra
- Males: Base of penis and scrotum
- Both: Contains superficial and deep perineal pouches

Front 70

anal triangle

Back 70

Posterior Triangle
- Contains the Anus/anal canal, ischiorectal fossa/ischioanal fossa, and Alcock’s/pudendal canal

Front 71

perineum

Back 71

 Lies below the pelvic diaphragm
 Entire pelvic outlet
 Diamond-shaped
o Anterior: symphysis pubis
o Posterior: Tip of coccyx
o Lateral: Ischial tuberosity
 May be divided into 2 triangles by joining the Ischial Tuberosities by an imaginary line (Urogenital and Anal Triangle)
 The Perineum is the entire Pelvic Outlet Anatomically

Front 72

sphincter ani internus

Back 72

Subcutaneous part:
origin,
Encircles lower end of the anal canal, no bony attachments
Superficial part- Coccyx
Deep part-Encircles upper end of anal canal, no bony attachments

Front 73

urogenital triangle boundaries and layer attaches membransou

Back 73

Front: pubic arch
Lateral: ischial tuberosities
Membranous layer attaches:
On either side of triangle to pubis and ischium
Behind to posterior free margin of perineal membrane

Front 74

membranous layer urogenital triangle

Back 74

Becomes Colle’s fascia
- Covers the urogenital triangle, penis, and scrotum
- Attachment: Continuation of Scarpa’s fascia 1-2cm below the inguinal ligament attaches to the fascia lata of inner thigh but at perineum – attaches to ischiopubic rami laterally and posteriorly with pernieal membrane and superior fascia that covers urogenital triangle

Front 75

fatty layer urogenital tirangle

Back 75

Continuous with the ischiorectal fossa and thigh
- Scrotum: Dartos muscle
- In females, continuous with the fat at the area of the labia majora and mons pubis

Front 76

perineal membrane

Back 76

Attaches to the pubic arch, ischiopubic ramus, and to an area posteriorly; fascia fuse behind superficial perineal transverse muscle and above the deep transverse perineal muscle
 Also called the inferior layer of urogenital diaphragm

Front 77

deep perineal fascia

Back 77

Continuous with the deep fascia of the anterior abdominal wall
 Potential space beneath where fluids can accumulate
 Buck’s fascia in penis

Front 78

pudendal canal contents

Back 78

o Dense fat – Continuation of Camper’s fascia; supports anal canal
o Pudendal nerve and internal pudendal vessels in pudendal canal
o Inferior rectal vessels and nerve

Front 79

ischiorectal fossa

Back 79

Wedge-shaped space on the each side of the anal canal
 Base: Formed by the skin and superficial fascia (ischiorectal fat  Continuation of superficial fatty layer; pudendal nerve and internal pudendal vessels within the pudendal canal located at the lateral wall of ischiorectal fossa close to the fascia that covers the obturator internus muscle)
 Edge – Formed by the junction of the medial and lateral walls
Medial wall: Formed by anal canal and sloping levator ani muscle
Lateral wall: Formed by the lower part of the obturator internus muscle (covered by pelvic fascia)
-filled w/ fats that support anal canal, allows distention

Front 80

perineal body

Back 80

Small mass of fibrous tissue
Attached to center of the posterior margin of urogenital diaphragm
Larger structure in females and it serves to support the posterior vaginal wall
Provides for muscle attachment in the perineum for both sexes

Front 81

deep perineal pouch contents n male

Back 81

Membranous urethra – ½ in. long, surrounded by sphincter urethrae muscle
o Sphincter urethrae
o Bulbourethral glands – Lies beneath the sphincter; ducts pierce perineal membrane and enter penile urethra
o Deep transverse perineal muscles
o Internal pudendal vessels and branches – Enters pouch and passes forward giving rise to artery to bulb of penis, deep artery of penis, dorsal artery of penis
o Dorsal nerve of penis – Passes forward through the pouch and supplies the skin of the penis

Front 82

deep perineal pouch female

Back 82

o Part of urethra
o Part of vagina
o Sphincter urethrae
o Deep transverse perineal muscles
o Internal pudendal vessels
o Dorsal nerves of the clitoris

Front 83

superficial perineal pouch

Back 83

Floor: Colle’s fascia
Roof: perineal membrane
 Muscles are covered by deep/investing fascia or Gallaudet’s fascia
o Bulbospongiosus muscle
 Covers the roof/bulb of penis and posterior corpus spongiosum
 Functions to empty urethra of urine and to assist in erection of penis
o Ischiocavernous muscle:
 Covers the crura of the penis
 Assist erection of penis
o Superficial transverse perineal muscle:
 Lie on posterior part
 Arise from ischial ramus
 Inserted into perineal body
 Fix perineal body in center of perineum during defecation
 Supplied by perineal branch of pudendal nerve

Front 84

contents male sup. perineal pouch

Back 84

Root (bulb and crura) of penis and muscles associated with it
o Proximal portion of spongy urethra
o Branches of internal pudendal vessels and nerves

Front 85

contents female sup. perineal pouch

Back 85

Clitoris
o Bulbs of the vestibule
o Bulbospongiosus muscle
o Ischiocavernous muscle
o Superficial transverse perineal muscle
o The greater vestibular glands

Front 86

sup perineal pouch

Back 86

Boundaries:
Floor: Perineal membrane
Roof: Superior fascia of urogenital diaphragm
 Musculofascial diaphragm that fills the gap of the pubic arch.
 It is formed by the sphincter urethrae and the deep transverse perineal muscle, enclosed between a superior and inferior layer of fascia or perineal membrane
 Anterior: Fascia fuse, small gap beneath symphysis pubis
 Posterior: Fascia fuse with each other and with Colle’s fascia and perineal body
 Lateral: Attached to pubic arch
 The deep perineal pouch is a closed space within/between superior and inferior layer of fascia.

Front 87

lymph drainage pelvis

Back 87

4 primary group of nodes (Moore):
1. External Iliac LN.
- Receive mainly from inguinal lymph node
- Drain to common iliac lymph node
2. Internal Iliac LN.
- Receive from inferior pelvic viscera, deep perineum and gluteal region.
- Drain to common iliac lymph node
3. Sacral LN
- Receive from posteroinferior pelvic viscera
- Drain to Internal Iliac or Common Iliac lymph node
4. Common Iliac LN.
- Receive from the ither 3 group of nodes then drain to paraaortic/caval/lumbar lymph nodes

Front 88

sup. transverse perineal ms

Back 88

o: ischial tub, i:perineal body, a: fixs perineal body in center

Front 89

bulbospongiosus

Back 89

o-perineal body/median raphe, i- expansion over corpus spongiosum/cavernosum, a- empties uretrha after micturition and ejaculation, helps erection

Front 90

ischiocavernosus ms

Back 90

o- ischial tuberosity/ramus, i- expansion underside of crus
a- assists in erection, compress crus penis

Front 91

deep transverse perineal ms both

Back 91

o-ramus ischium, i- perineal body, a- fixes perineal body

Front 92

sphincter urethrae

Back 92

o- fascia/famus pubis
i- encircles urethra, perineal body, a- compress membranous urethra

Front 93

what are all ms perinuem supplied by?

Back 93

perineal branch pudendal n

Front 94

arteries true pelvis

Back 94

internal iliac/hypogastric a: From common iliac artery dividing at area of pelvic brim at the upper margin of greater sciatic foramen
- Has an anterior and posterior division
- Named according to the organs that they supply

Front 95

anterior division internal illiac artery

Back 95

Mainly supply visceral but some with parietal part (Moore)
1. Obturator
It is the proximal patent part of the umbilical artery
Supply most of the pelvic muscles
2. Umbilical
Superior vesical artery
Artery to ductus deferens in males
3. Uterine
Homolog to artery of ductus deferens in male
Crosses URETER superiorly (“water under the bridge”: Water = ureter, Bridge = uterine artery)
Has two branches:
 Vaginal branch: Anastomose with vaginal artery
 Ascending branch: Runs along lateral margin of uterus to supply the body and fundus of the uterus
 Tubal branch and Ovarian branch
 Both will anastomose with Ovarian artery to supply Uterine Tube and Ovary
4. Inferior Vesical
- Seen in male only
- Replaced by vaginal artery in female
- Artery to ductus deferens
- Prostatic artery
5. Middle Rectal
- Commonly arise with inferior vesical artery and anastomose with superior rectal artery from inferior mesenteric artery AND inferior rectal artery from internal pudendal artery
6. Vaginal
- Homolog to inferior vesical artery of male
- Anastomose with vaginal branch of uterine artery
Four Arteries True Pelvis
Muscles of the Urogenital Triangle
SECTION B UERMMMC Class 2014 ANATOMY 12 | 13
7. Internal Pudendal
- Inferior vesical artery will branch out before the Internal Pudendal artery will leave the pelvis between piriformis and coccygeus ms. by passing inferior part of greater sciaticforamen
- Pass around posterior aspect of ischial spine or sacrospinous ligament
- Enter the ischioanal fossa through lesser sciatic foramen then pass through pudendal canal/alcock canal.
- Exit and going to medial side of ischial tuberosity to give rise to deep and dorsal artery of the penis/clitoris.
8. Inferior Gluteal

Front 96

post division internal iliac a

Back 96

1. Iliolumbar
- Ascend across pelvic inlet
- Iliacus artery and lumbar artery
2. Lateral Sacral
- Descend in front of sacral plexus
3. Superior Gluteal
- Leaves penis via greater sciatic foramen
- Supplies the gluteal region

Front 97

median sacral a

Back 97

Arises at the junction of common iliac a., runs along the anterior surface of sacrum and coccyx
- Gives off the 5th pair of lumbar a.
- Represent the caudal end of embryonic dorsal aorta

Front 98

ovarian a

Back 98

- Branch of abdominal aorta (L1) below the renal a. (retroperitoneal)
- Go to infundibulopelvic ligament, enters the pelvis and gives off branches to the ovary and fallopian tube  anastomose with branches from uterine a.
- Testicular a. for male; does not enter pelvis

Front 99

sup rectal a

Back 99

Terminal branch of the inferior mesenteric a.
- Supply rectum and upper half of anal canal
- Direct continuation of inferior mesenteric artery

Front 100

venous drainage pelvis

Back 100

Median sacral
Drains to left common iliac v.
2. Ovarian v.
Right: IVC
Left: Renal v.
3. Superior rectal v.
To inferior mesenteric vein to splenic vein
4. External iliac vein
Does not enter true pelvis
Continuation of femoral v. (behind inguinal ligament)
Joins internal iliac v. to become common iliac v.
Receives inferior epigastric and deep circumflex v.
5. Internal iliac v.
Joins tributaries corresponding to branches of IEA
Joins external iliac v. to form common iliac v.
Note:
Right and left common iliac vein joins at level of L5 to form IVC.

Front 101

ns pelvis

Back 101

Parasympathetic – pelvic splanchic nerve (lateral horn of S2, S3, S4) or nervi erigentes
 Sympathetic – conciliation of lumbar sympathetic chain and aortic plexus (plexuses around the area of aorta)
o Superior hypogastric plexus
 Continuation of the lumbar sympathetic ganglia and inferior mesenteric plexus (one of the aortic plexuses)
 Enter the pelvis as right and left hypogastric plenerve
 Divide into nerves to form right and left inferior hypogastric plexuses (receive fibers coming from pelvic splanchnic nerves forming the pelvic plexuses)
o Ovarian plexuses does not come from pelvic plexuses but, from the aortic plexuses (rectal, uterovaginal, vesical)
 Sacral Plexus: formed by anterior rami of L4-L5 ad S1-S4
 Branches to Pelvic Area:
o Pudendal Nerve (S2-S4)
o Nerves to Piriformis ms
o Pelvic Splanchnic nerve
 Lumbar Plexus
o Lumbosacral (L4-L5)
o Obturator nerve (L2-L4)

Front 102

pudendal n

Back 102

Chief nerve supply to the perineum
 Supply the muscles and most of the skin
 Arises from anterior division of ventral/anterior rami of S2-S4 (branch of sacral plexus from L4-S3/S5)
 Leaves the pelvis towards the greater sciatic foramen and it crosses and winds around the ischial spines medial to internal pudendal vessels  Enters pudendal canal
 Three branches

Front 103

pudendal canal

Back 103

(Alcock’s Canal) – Essential horizontal passageway within the obturator fascia that covers medial aspect of obturator internus and lines the lateral wall of ischioanal fossa.

Front 104

pudendal block

Back 104

15 cm 22 gauge needle with guard introducer
 10-15 ml local anesthesia
 Two types of procedure:
1. Transperineal or Transvaginal
- Using both hands, gliding the needle to the area of ischial spines; middle and index finger of left through the vaginal canal palpating for the left ischial spines, once palpated, will be using the right hand to pull syringe and direct it under and beyond ischial spine to internal pudendal nerve
2. Perineal
- Palpate for the ischial tuberosity; then needle is introduced subcutaneously through buttock into pudendal canal along the medial side of tuberosity.

Front 105

complications w/ pudendal block

Back 105

Hematoma (hitting internal pudendal vessels
 Under & beyond ischial spine – Int. pudendal n.
 Incompletely w/drawn & directed laterally to ischial tuberosity – Perineal br of post. femoral cutaneous n.
 Radial fashion toward vagina & anus

Front 106

epistiotomy

Back 106

Tearing of perineum
 Surgical incision made through perineal skin in posterolateral direction to avoid anal sphincter
 Often made to enlarge the vaginal orifice due to arrested or protracted descent of the fetus
 2 type of Episiotomy:
1. Median Episiotomy: Perineal body is major structure incised
- Scar produces as wound heals will not greatly different from fibrous tissue surrounding it.
2. Mediolateral Episiotomy: Do not appear to increase incidence of severe laceration
- Less likely to be associated to anal sphincter damage

Front 107

3 branches pudendal nerve

Back 107

Inferior rectal nerve
- Given off before it enters the pudendal canal
- Crosses the ischiorectal fossa to supply external anal sphincter, mucosa of lower anal canal and perianal skin
2. Perineal nerve
- Supplies all the muscles of urogenital triangle and the skin of the scrotum or labia majora(superficial perineal pouch)
- Arise at the end of the pudendal canal.
- Communicates with inferior rectal nerve
- Will divide into superficial part, which will give rise to scrotal/labial branch (cutaneous), and deep branch, supplies the muscle of superficial, deep, skin of vestibule and mucosa of inferior most part of vagina
3. Dorsal nerve of the penis (male) or dorsal nerve of the clitoris (female)
- Go all the way up to deep perineal pouch
- Primary sensory nerve of male and female reproductive organ especially the sensitive glans at the distal end