Pelvis perineum.pptx

Pelvis perineum
1/7/2023
Yared T(Ass. Professor)
1

Pelvis perineum
 Formed by:
Skin
Subcutaneous tissue
Muscles
Bones
Fascia
Visceral organs(urinary, digestive and
reproductive)
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Bony pelvis
 Formed by 4 bones united by 4 joints
 Bones: 2 hip bones, sacrum and coccyx
 Joints: 2 sacroiliac joints, pubic symphysis and
sacrococcygeal joint
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Ilium
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 Located superior to the acetabulum
Parts of ilium
 Body
 joins ischium and pubis to acetabulum
 Ala (wing)
 bordered superiorly by iliac crest
 Posteriorly it has; anterior, posterior and inferior
gluteal lines (origins of gluteus minimus,
medius and maximus muscles)
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…cnt
 Iliac crest
 a line joining the most superior point of the
bilateral iliac spine.
 cross the 4th lumbar spine (L4)(iliac
tuberosity)
 this is a guide to lumbar spinal tap because
the spinal cord ends around L1/L2
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Landmarks:
 ASIS
 AIIS
 PSIS
 PIIS
 Greater
sciatic notch
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Ischium
 Forms posteroinferior part of the acetabulum and
hip bone
 Body
 joins ilium and superior ramus of pubis to form
acetabulum
 Ramus
 fuses with the inferior ramus of pubis
 The pubic arch or sub pubic angle is formed by
joined rami of ischium and pubis, bilaterally
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Landmarks
 ischial spine
 lesser sciatic
notch
 ischial tuberosity
that supports
body during
sitting
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Pubis
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 Forms anterior part of the acetabulum and
anteromedial part of hip bone
 Body
 has a symphyseal surface for articulation with
the contralateral pubis
 Rami
 two (inf. & sup.) which supports its body
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Landmarks
 pubic crest (medial) - ends at pubic tubercle (lateral)
 superior ramus - has a ridge called pecten pubis or
pectineal line
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Sacrum
 Triangular shaped,
formed by five fused
vertebrae
 Forms the posterior wall
of the pelvis
 Articulates with L5 and
iliac bone
 Transfers the weight of
the body to the lower
extremities
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Coccyx
 tail bone
 composed
of 4 fused
vertebrae
 articulates
with
sacrum
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Pelvic Cavity
 Has two part;
1) true and
2) false pelvis
 True pelvis has-
inlet & outlet
 Has true border.
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Pelvic Cavity
 Is divided by pelvic brim into 2 parts:
1.pelvis major (false pelvis)
 Also called greater pelvis
 lies between iliac fossa; is part of abdominal wall
 Superior to the pelvic inlet
 Bounded by the abdominal wall anteriorly, the iliac alae
laterally, and the L5 and S1 vertebrae posteriorly
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2. pelvis minor (true pelvis)
 Is also called lesser pelvis
 actual pelvis; contains pelvic viscera(rectum,
bladder, and reproductive organs)
 Between the pelvic inlet and the pelvic outlet
 Bounded by the pelvic surfaces of the hip bones,
sacrum, and coccyx
 Limited inferiorly by the musculofascial pelvic
diaphragm (levator ani).
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Pelvic inlet
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 Bounded by:
 Superior margin of the pubic symphysis
 Posterior border of the pubic crest
 Pecten pubis
 Arcuate line of the ilium
 Anterior border of the ala of the sacrum
 Sacral promontory
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Pelvic outlet
 bounded by:
 Inferior margin of the pubic symphysis
anteriorly
 Inferior rami of the pubis and ischial
tuberosities anterolaterally
 Sacrotuberous ligaments posterolaterally
 Tip of the coccyx posteriorly
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MUSCLES OF PELVIC WALLS AND FLOOR
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Sexual differences in bony pelvis
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 sexual differences are related to:
 heavier build and larger muscles of men
 adaptation in women for childbearing
 The male pelvis is heavier ,thicker, & has
more prominent bone markings
 The female pelvis is wider, shallower, lighter,
and rounder than the male and has a larger
pelvic inlet and outlet
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Types of female pelvis
 Gynecoid
 Android
 Anthropoid
 platypelloid
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A and C are most common in males
B and A in white females
B and C in black females
D is uncommon in both sexes 1/7/2023

Pelvic diameters (Conjugates)
 shape and size of the pelvic inlet are significant
during labor
 are noted radiographically or manually
 pelvic diameters are :
-Inlet diameter, pelvic cavity & outlet
diameter
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Inlet Diameters
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 oval (female) or heart shaped (male) opening
 larger in females than in males
 is demarcated by linea terminalis which
separates the false from the true pelvis.
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The diameters of the inlet are:
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1.The anterioposterior (true conjugate) diameter
 is measured between the midpoint of sacral
promontory and the upper border of the pubic
symphysis
 is 10 cm in male and 11cm in female
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…cnt
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2.The transverse diameter
 maximum distance that can be measured
between similar points on the opposite sides
of pelvic brim
 is 12.5 cm in male and 13 cm in female.
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…cnt
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3. The oblique diameter
 is measured from one iliopubic eminence to
the opposite sacroiliac joint
 is 12cm in male and 12.5 cm in female
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Pelvic outlet
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 diamond shaped opening in both
 much wider in females than males
 Bounded:
 anteriorly by pubic symphysis
 posteriorly by sacrum and coccyx
 laterally by ischial tuberosities
 is partially closed because of coccyx is curved
in.
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Diameters of the outlet are:
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1.The anterioposterior diameter
 is usually measured from apex(tip) of the
coccyx to the midpoint of the lower rim of
pubic symphysis
 is 8cm in male and 12.5 in female
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…cnt
41
2. The transverse diameter
 between ischial tuberosities, from the lower
border of their medial surfaces
 is 8.5 cm in male and 11.8 cm in female.
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…cnt
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3. The oblique diameter
 from midpoint of the sacrotuberous ligament
on one side to the junction of ischial and
pubic ramus on the other
 is 10 cm in male and 11.8cm in female.
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Nerves of pelvis
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 Pelvis is innervated mainly by sacral and
coccygeal nerves and pelvic part of ANS
 This nerves includes
-sacral plexus
- coxygeal plexus
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Sacral plexus
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 Origin anterior primary rami of L4–S4
 L4 is shared by both lumbar & sacral plexus
 sacral nerves emerge from the anterior sacral
foramina and unite in front of piriformis where
they are joined by the lumbosacral trunk
 Branches from the plexus supply:
 the pelvic muscles
 the muscles of the hip
 the skin of the buttock and the back of the thigh
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Sacral Plexus
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Branches
 Superior gluteal nerve - gluteus medius, minimus,
tensor fascia lata
 Inferior gluteal nerve – gluteus maximus
 Nerve to quadratus femoris
 Nerve to piriformis
 Nerve to obturator internus
 Posterior cutaneous nerve of the thigh
 The plexus itself terminates as the pudendal
nerve and the sciatic nerve
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Pudendal nerve
 forms from ventral divisions of S2 to S4
 It leaves the pelvic cavity through the greater
sciatic foramen, inferior to the piriformis muscle,
and enters the gluteal region;
 innervates skin and skeletal muscles of the
perineum, including the external anal and external
urethral sphincters
 Mediates the act of erection
 Voluntary control of urination
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Sciatic nerve
 The largest nerve in the body
 Formed by the anterior rami of spinal nerves L4 -S3
 Passes through the greater sciatic foramen inferior
to the piriformis to enter the gluteal (buttock) region
 It then descends along the posterior aspect of the
thigh to supply the posterior aspect of the lower
limb
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Coccygeal plexus
 Formed from S4 ,S5 and coccygeal nerve
 Supply part of levator ani, coccygeus and anal
sphincter
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Pelvic Viscera
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The organization of pelvic viscera from anterior to
posterior:
 In the male: bladder, prostate and male genital
organs and rectum
 In the female: bladder, uterus and female genital
organs and rectum
 The pelvic viscera are partly covered by
peritoneum in their upper aspects but are
extraperitoneal inferiorly
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Urinary bladder
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 Smooth, collapsible, muscular sac that stores
urine
 Position
 shape, size and position vary with amount of urine
and age
 In adults: empty bladder lies in pelvis minor
posterior and slightly superior to pubic bones
 In infants: found in abdomen
 Enters pelvic major at about 6 years of age and
pelvic minor at puberty
 When filled ascends to pelvic major and abdomen
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 Parts
 empty bladder has the form of pyramid
 4 surfaces: superior, 2 inferolateral and posterior
(fundus).
 anterior end is termed as apex
 inferior end is termed as neck
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Internal structure
 The interior of the bladder has openings for both
ureters and the urethra
 The triangular region of the bladder base outlined by
these openings is called the trigone
 The ureters open at superior angle of trigone and the
urethra open at inferior angle.
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Arterial supply
 Branches of internal iliac arteries
 Superior vesical artery: supply anterosuperior parts
 Inferior vesical artery and Vaginal artery: supply fundus in
male and female, respectively
 Obturator and inferior gluteal arteries: small branches
 Venous drainage
 Correspond to arteries and drain into internal iliac vein
 Lymphatic drainage
 Superior part: to external iliac lymph nodes
 Inferior part: to internal iliac lymph nodes
 Innervation
 Parasympathetic fibers from pelvic splanchnic nerves
(S2,S3,S4)
 Motor to muscle and inhibitory to internal sphincter
 Sympathetic fibers from T11,T12,L1 & L2 through
vesical plexus
 inhibitory
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Urethra
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Male urethra
 long, about 15-
20cm
 has 3 portions:
1.prostatic
urethra
 about 3cm long
 passes through
prostate
 widest and most
dilatable part
 ejaculatory
ducts open on
each side of
prostatic utricle
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2.membranous urethra
 shortest (1-2cm), thinnest and narrowest
 traverse urogenital diaphragm
 surrounded by external urethrae sphincter muscle
and perineal membrane
 posterolateral to it on each side is bulbourethral
gland and duct
3.spongy urethra
 longest, about 15 cm
 passes through bulb of penis and corpus
spongiosum and ends at external urethral orifice
 ducts of bulbourethral glands opens into proximal
part
 expanded in bulb and in glans penis
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Blood supply
 arteries: branches to prostate, bulb and urethral
artery
 veins: accompany arteries
 Innervation
 branches of pudendal nerve
 pelvic splanchnic nerves
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Female urethra
shorter (4cm)
 It opens 2 cm posterior to the clitoris in vestibule of vagina
 Its inferior end is surrounded by sphincter urethrae muscle
 Urethral glands are found in superior part called
paraurethral glands
 Blood supply: internal pudendal and vaginal vessels
 Innervation: pudendal nerve and pelvic splanchnic nerves
 Lymphatic drainage: sacral and internal iliac lymph nodes
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Male internal genital organs
Include :
 The testes (male gonads),
 System of ducts
 Epididymis,
 Ductus deferens,
 Ejaculatory ducts, and
 Urethra,
 Accessory sex glands
 seminal vesicles,
 prostate, and
 bulbourethral glands,
 Supporting structures
 the scrotum and
 the penis
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The Testes
 Small, oval shaped organ
 Housed in the scrotum
 Produces:
 Sperm
 androgens.
 Coverings
 tunica vaginalis:- is serous membrane which has
 Parietal layer
 Visceral layer.
 Tunica albuginea
250 lobules per testis
 Each lobule has up to 4 seminiferous tubules
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The Fetus: Formation of Testes
 Testes formed inside body cavity (abdominal cavity).
 Descent of testis: During seventh month.
• Each testis:
– moves through abdominal musculature
– are accompanied by pockets of peritoneal cavity
 Accessary structures accompany testis during descent
 Form body of spermatic cord:
 ductus deferens
 testicular blood vessels, nerves, and lymphatic vessels
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Structure of testes
 seminiferous tubules: site of spermatogenesis
contain :- germ cell; Sperm forming cells
- Sertoli cells (supporting cells)
- form blood-testis barrier
-support developing sperm cells
- produce fluid & control release of sperm into lumen
- secrete inhibin which slows sperm production
 Interstitial spaces: surround the seminiferous tubules.
 Contain interstitial (Leydig) cells
 produce hormones called androgens.
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Structure of testes….
 Rete testis
= network of canals in the mediastinum testis
 Efferent Ductules
 15–20 large efferent ductules:
 connect rete testis to epididymis
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Testes cont…
 Series of tubes (path of sperm )
Seminiferous tubules (site of sperm formation)
Straight ducts
Rete testis
Efferent ductule
Epididymis (where sperm matures & temporarily stored)
Ductus deferens
Ejaculatory duct
urethra
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The epididymis
 The epididymis is a comma-shaped structure composed of
an internal duct and an external covering of connective
tissue.
 Has three parts:-head, body and tail.
 Its head lies on the superior surface of the testis, while the
body and tail are posterior to the testis.
 Internally, the epididymis contains a long, convoluted duct
of the epididymis, which is approximately 7m.
 Sperm must reside in the epididymis for a period of time to
become mature and fully motile.
 If sperm are not ejected from the male reproductive
system in a timely manner, the old sperm degenerate in
the epididymis.
Yared T
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Epididymis cont…
 Testes produce physically immature spermatozoa that can
not fertilize an oocyte
 Other parts of reproductive system are responsible for:
 functional maturation, nourishment, storage, and transport
 3 Functions of the Epididymis
1. Monitors and adjusts fluid produced by seminiferous
tubules
2. Recycles damaged spermatozoa
3. Stores and protects spermatozoa:
– facilitates functional maturation of sperm
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Male internal genital organs
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.Ductus (vas) deferens
 Thick walled muscular tube, about 45cm long.
 Continuation of ductus epididymis
 Course
 Begins in tail of epididymis and ends by joining duct of
seminal vesicle
 Ascends in spermatic cord, passes through inguinal
canal and cross over external iliac vessels to enter
pelvis minor
 Enlarges to form ampulla posterior to bladder
 Finally, it narrows and joins duct of seminal vesicle to
form ejaculatory duct.
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Blood supply to ductus deference
 Usually from-superior vesical artery
 Some times-from inferior vesical artery
 Vein –to testicular vein
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Clinical Correlation
Male Sterilization
 The common method of sterilizing males is a
deferentectomy, popularly called a vasectomy.
 During this procedure, part of the ductus deferens is
ligated and/or excised through an incision in the
superior part of the scrotum .
 Hence, the subsequent ejaculated fluid from the
seminal glands, prostate, and bulbourethral glands
contains no sperms.
 The unexpelled sperms degenerate in the
epididymis and the proximal part of the ductus
deferens.
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Ejaculatory ducts
2.5cm long.
Formed by
union of ducts
of seminal
vesicle and
ductus
deferens.
Traverse
prostate.
Open into
posterior wall
of prostatic
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Blood supply to ejaculatory duct
 From superior or inferior vesical artery
 Vein-to prostatic & vesical venous plexus
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Seminal vesicles
Thin-walled and pear-shaped
 About 5 cm long
 Lies between fundus of bladder and rectum
 Secrete a fluid which ;
 accounts for about 60% of the volume of the semen
-It is a yellowish, viscous, alkaline fluid
 The ducts of the seminal vesicles join with the vas
deferens to form the ejaculatory ducts.
 Sperm and seminal fluid mix in the ejaculatory
duct to enter the prostatic urethra together during
ejaculation
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Contents Of Seminal Secretion
 Fructose
 Monosaccharides
 Citric Acid
 Coagulation Proteins
 Prostaglandins
 Fibrinogen
Arterial Supply and Venous
Drainage
 The arteries derive from the
inferior vesical and middle
rectal arteries.
 The veins accompany the
arteries and have similar
names
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Prostate
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 Surrounds prostatic
urethra
 Parts: base, apex, 4
surfaces (posterior,
anterior and 2
inferolateral)
 has 15-20 ducts
 It is 3 cm long, 4 cm wide,
and 2 cm in AP depth)
 about 20 g.
 largest accessory gland
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 is divided into 2 lateral lobes (site of carcinoma -
may be felt on palpation through the rectum) and a
middle lobe (the upper part is the site of benign
hypertrophy)
 Secrete milky, alkaline fluid
 prostate progressively enlarges after 50 years of
age.
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Parts prostate gland
 Apex:-directed downwards; 1.5 cm below the margin of
symphysis pubis
 Base:-continuous with neck of bladder.
 Surfaces:-
 The anterior surface is separated from the pubic
symphysis by retroperitoneal fat in the retropubic space.
 A posterior surface that is related to the ampulla of the
rectum.
 Inferolateral surfaces that are related to the levator ani.
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Blood supply prostate
 Inferior vesical-major
 Middle rectal & internal pudendal artery
 Vein-prostatic plexus-drain to internal iliac
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Functions of the Prostate Gland
 Produce milky secretions
 Prostatic secretion makes from 20 -40% of volume of
the semen.
 Their secretion has the following advantages
1. assist motility of spermatozoa
2. help to nourish the spermatozoa
3. makes the semen more liquefied
4. its alkalinity protects sperm as it passes through the
acidic vagina
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Clinical Condition
Hypertrophy of Prostate
 The prostate is of considerable medical interest
because enlargement or benign hypertrophy of the
prostate (BHP) is common after middle age, affecting
virtually every male who lives long enough.
 An enlarged prostate projects into the urinary bladder
and impedes urination by distorting the prostatic
urethra.
 The middle lobule usually enlarges the most and
obstructs the internal urethral orifice.
 The more the person strains, the more the valve-like
prostatic mass occludes the urethra.
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Innervation to internal genital organs
 All internal genital structures such as;
 vas deference
 ejaculatory duct
 seminal vesicle and
 prostate are innervated;
 Symphatatic-T12-L3(abdominopelvic splanchnic)
 Parasympha-S2 &S3(pelvic splanchnic)
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Bulbourethral gland/Cowper
glands/
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 Pea size
 lie posterolateral to membranous urethra,
largely embedded in External urethral sphincter
muscle
 duct passes through perineal membrane and
open in proximal spongy urethra in bulb of
penis
 Their mucus-like secretion enters the urethra
during sexual arousal, before ejaculation.
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Female internal genital
organs
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1.Primary reproductive organs- ovaries
 Used to:
 Produce gametes
 Produce female sex hormones (estogen and
progesterone)
2. The accessory ducts (uterine tubes, uterus,
and vagina)
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Uterus
105
 hollow, thick walled, pear-shaped muscular
organ
 functions to receive, retain, and nourish the ovum
 located between bladder and rectum
 For non pregnant, uterus is:
 7-8cm long, 5-7cm wide, 3cm thick
 It is larger in woman who have borne children
 projects superoanteriorly over bladder
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Parts:
body: expanded superior 2/3
fundus: superior part of body
cervix: cylindrical inferior third
isthmus: junction between body and cervix
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Cervix
 Narrow part
 Characterized by internal and external os.
 Its mucosa contains cervical glands that secrete a mucus
 Mucus fills the cervical canal and covers the external os,
presumably to block the spread of bacteria from the vagina into
the uterus
 Cervical mucus also blocks the entry of sperm, except at
midcycle, when it becomes less viscous and allows sperm to pass
through.
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Position of uterus:
 usually bent anteriorly (anteflexed) between
cervix and body and the whole uterus is inclined
anterioly (anteverted)
 It is less anteverted when the bladder is full
 the uterus is often turned backward, or retroverted
in older woman
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The Uterine Wall
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 3 layers:
1.Perimetrium
 outermost serous layer composed of visceral
peritoneum
2.Myometrium
 bulky middle layer, composed of interlacing
bundles of smooth muscle
 contracts during childbirth to expel the baby
3.Endometrium
 simple columnar epithelium underlain by a
thick lamina propria of highly cellular
connective tissue
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Endometrium
 For Implantation of embryo
 has two strata/layer/
 stratum functionalis (functional layer)
 undergoes cyclic changes in response to blood levels of
ovarian hormones and is shed during menstruation (28
day cycle)
 stratum basale
 thinner deeper layer which forms a new functionalis layer
after menstruation ends
 unresponsive to ovarian hormones
 The endometrium has numerous uterine glands that
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Blood supply
 Internal iliac Artery-uterine artery- arcuate
arteries within the myometrium-radial
branches into the endometrium-straight
arteries to the stratum basalis- spiral arteries
to the stratum functionalis
 spiral arteries undergo repeated degeneration and
regeneration, and it is their spasms that actually
cause the functionalis layer to be shed during
menstruation
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 Vein-uterine vein
 Lymphatics
 aortic, external iliac, internal iliac and sacral lymph
nodes
 Innervation
 from inferior hypogastric plexus
 parasympathetic - pelvic splanchnic
 sympathetic – symphatetic trunk
1/7/2023

Uterine tubes
116
 10-12cm long
 carry oocytes from ovaries and sperms from uterus to
site of fertilization (ampulla)
 opens at its proximal end to horn of uterus and distal
end into peritoneal cavity
 Parts:
 infundibulum: funnel shaped, margin have finger like
processes called fimbriae which spread over ovary
 ampulla: middle wide part, site of fertilization
 isthmus: narrow part which enters uterus
 uterine (intramural) portion: passes through
myometrium
1/7/2023

1/7/2023
117

118
 Arterial supply: from uterine and ovarian
arteries
 Venous drainage: to uterine and ovarian veins
 Lymphatics: to aortic lymph nodes
 Innervation: from ovarian plexus and uterine
plexus
1/7/2023

1/7/2023
119

Ovaries
120
 Oval shaped gland, about 3cm long
 Lies on the lateral wall of the pelvis major/in
ovarian fossa/
 The ovarian fossa is framed by the external iliac
vessels superiorly, the obliterated umbilical artery
anteriorly, the ureter and internal iliac vessels
posteriorly. Obturator nerve and vessels are lateral
to the ovarian fossa.
 Each ovary is held in place within the peritoneal
cavity by several ligaments
 ovarian ligament
 suspensory ligament
 mesovarium
1/7/2023

…cnt
 ovarian ligament
 anchors the ovary medially to the uterus
 suspensory ligament
 anchors the ovaries laterally to the pelvic wall
 mesovarium
 suspends the ovaries between the fallopian tubes and the
uterus
 Both the suspensory ligament and the
mesovarium are part of the broad ligament
121
1/7/2023

1/7/2023
122

123
 Arterial supply: ovarian arteries
 Venous drainage: ovarian veins; right drains
into inferior vena cava and left into left renal
vein
The ovarian blood vessels reach the
ovaries by traveling through the
suspensory ligaments and mesovaria
 Lymphatics: to aortic lymph nodes
 Innervation: ovarian plexus and vagus
1/7/2023

1/7/2023
124

Rectum
125
 Fixed terminal part of large intestine
 Begins at the level of S3
 about 12-15cm long, follows curves of sacrum
and coccyx
 Ends 3-4cm anteroinferior to tip of coccyx by
turning posteroinferiorly to become anal canal
 Terminal part dilate called rectal ampulla
1/7/2023

1/7/2023
126

127
Arterial supply
To rectum
 Superior rectal artery
 Middle rectal arteries
 Inferior rectal arteries
1/7/2023

PERINEUM
128
 diamond shaped inferior to pelvic diaphragm between
thighs
 Boundaries:
 anteriorly by the symphysis, the inferior ramus of the pubis and
the ramus of the ischium
 Posteriorly it is bound by the lower part of the sacrum and the
coccyx connected to the ischial tuberosity by the sacrotuberous
ligament
 The superficial part of this region is called the perineum
including the external genitalia (in the urogenital triangle)
and the anus (in the anal triangle)
1/7/2023

1/7/2023
129

1/7/2023
130

131
…cnt
 Divided into 2 triangles by line joining ischial
tuberosities
 Anal triangle: contains anus and ischioanal fossa
 Urogenital triangle: contains external genitalia
 Inferior pelvic aperture (pelvic outlet) is closed by
 Urogenital diaphragm: anterior part
 Pelvic diaphragm: posterior part
1/7/2023

132 1/7/2023

Pelvic diaphragm
133
 Levator ani and coccygeus form the pelvic
diaphragm, separating the pelvis from the
ischiorectal fossa
 urethra, vagina and rectum pass through the pelvic
diaphragm
 pudendal nerve and vessels go around it
1/7/2023

Levator ani
134
 Muscular floor of the pelvis and supports the
viscera
 Has 3 parts:
1. puborectalis
2. pubococcygeus
3. iliococcygeus muscle
1/7/2023

1/7/2023
135

136
Coccygeus
 deep to the sacrospinous ligament
 has similar attachments with levator ani
 forms posterior part of pelvic floor
 Nerve supply: branches of S4 & S5
 Action: assist levator ani
1/7/2023

137 1/7/2023

138
 Urogenital diaphragm
 strong triangular membrane (thin sheet of muscle)
 Anterior and posterior fibers called deep
transverse perenial muscles
 Middle fibers called sphincter urethrae muscle
 A small gap at the apex of the triangle, posterior to
the pubic symphysis, exists for passage of the
deep dorsal vein and the dorsal nerve of the
penis or clitoris
1/7/2023

139 1/7/2023

…cnt
 The perineal membrane is pierced by:
 the urethra
 vagina
 ducts of the bulbourethral glands
 deep and dorsal arteries of the penis or
clitoris
1/7/2023
140

Anal triangle
141
 Boundaries
 tip of coccyx, line joining ischial tuberosities,
sacrotuberous ligament
 Contents
 anal canal, external anal sphincter and ischioanal
fossae
1/7/2023

142 1/7/2023

Anal canal
 Terminal about 4 cm part of large intestine
 Begins at u-shaped sling formed by puborectalis
muscle and ends at anus
 Descends posterioinferiorly
1/7/2023
143

1/7/2023
144

145
 Arterial supply
 superior rectal artery: superior to pectinate line
 Inferior rectal arterie: inferior to pectinate line
 Middle rectal arteries: anastomose with both
 Venous drainage
 Similar to artery
 Lymphatic drainage
 Superior part: to internal iliac lymph nodes
 Inferior part: to superficial inguinal lymph nodes
 Innervation
 Superior part: from inferior hypogastric and pelvic splanchnic
 Inferior part: from inferior rectal nerves
1/7/2023

Anal sphincter
 Smooth muscle
 On each side of superior
2/3rd
 contracts involuntarily
 prevent feces from leaking
 Not trained
 Skeletal muscle
 On each side of inferior 2/3rd
 contracts voluntarily
 prevent feces from leaking
 children learn to control during
toilet training
Internal External
1/7/2023
146

Urogenital triangle
147
 Consists of male and
 female external genital,urinary
structure
1/7/2023

Male external genitalia
 cutaneous sac ( fold of skin) that envelops the
testis
 Double layered
1. outer: highly pigmented skin
2. inner: Subcutaneous tissue (dartos fascia)
and dartos muscle which is responsible for
wrinkling of the skin.
1/7/2023
148

 scrotal raphe-externally
 Scrotal septum-internally
1/7/2023
149

 Innervations is:
 Genital branch of the genitofemoral nerve:
anterolateral surface.
 Anterior scrotal nerves, branches of the
ilioinguinal nerve anterior surface.
 Posterior scrotal nerves, branches of the
perineal branch of the pudendal nerve:
posterior surface.
 Perineal branches of the posterior femoral
cutaneous nerve: inferior surface.
1/7/2023
150

 Posterior scrotal branches of the perineal
artery from internal pudendal artery.
 Anterior scrotal branches of the deep external
pudendal artery, from femoral artery.
 Cremasteric artery from inferior epigastric
artery
1/7/2023
151

Veins and lymphatic's
 Scrotal veins accompany the arteries
corresponding veins
Lymphatic drainage
superficial inguinal lymph nodes
1/7/2023
152

Penis
153
 Organ of copulation and common outlet for urine
and semen
 Composed of 3 cylindrical bodies of erectile
tissue
1.Two Corpora cavernosa penis
 fused in median plane anteriorly
2.Corpus spongiosum penis
 urethra runs through it
 enlarged at the end to form the glans of the penis
1/7/2023

154 1/7/2023

155 1/7/2023

156
parts of penis
 Root
 attached portion
 consists of crura, bulb and muscles
 crura are posterior continuations of the corpora
cavernosa
 bulb is between crura in superficial perineal space
and is a continuation of the corpus spongiosum
 The crura are attached to the inferior ramus of the
pubis and the ramus of the ischium
1/7/2023

…cnt
 the bulb is attached to the undersurface of the
perineal membrane
 The urethra pierces the membrane in order to
enter the bulb
 The crura are surrounded by the
ischiocavernosus muscle and the bulb by the
bulbospongiosus, which expels the last drop of
urine
1/7/2023
157

158
 Body
 free part
 consists of corpora cavernosa and corpus
spongiosum
 distal end - glans penis, formed by corpus
spongiosum
 near tip is external urethral orifice
 The skin of the penis is thin and loose and the fold
over the glans with fasciae to form prepuce
1/7/2023

159 1/7/2023

160 1/7/2023

161 1/7/2023

162
 Arterial supply: dorsal arteries, deep arteries,
artery to the bulb & Superficial external pudendal artery
 Venous drainage:
 The superficial dorsal vein is in the midline and drains
skin, into a tributary of the saphenous vein
 The deep dorsal vein is in the fascia penis, in the
midline and drains the deep structures. It passes
through the gap of the perineal membrane and joins
the prostatic venous plexus.
 Lymphatics: superficial and deep inguinal lymph
nodes
 Innervation: dorsal nerve of penis, cavernous
nerves, ilioinguinal nerves 1/7/2023

Female external genital organs
 The external genitalia also called vulva
include
 Mons pubis
 Labia majora & labia minora
 Clitoris
 Vestibule structures
163
1/7/2023

164
…cnt
1/7/2023

165 1/7/2023

Vagina & Vaginal orifice
166
 Female organ of copulation
 Often called the birth canal
 provides a passageway for infant & menstrual flow
 Musculomembranous tube
 Anterior wall is shorter (7 cm) than posterior wall (9
cm)
 passes between levator ani muscles, pierces
urogenital diaphragm
 The upper end of the vaginal canal loosely surrounds the
cervix of the uterus, producing vaginal fornix
 posterior fornix, is much deeper
 2 lateral
 anterior fornices
1/7/2023

1/7/2023
167

168
1/7/2023

169
 Arteries: vaginal, internal pudendal, vaginal
branch of middle rectal
 Veins: vaginal venous plexus drain into internal
iliac veins
 Lymphatic drainage: internal and external iliac,
superficial inguinal lymph nodes
 Innervation: from uterovaginal plexus (in broad
ligament) derived from inferior hypogastric
plexus and pelvic splanchnic nerves
1/7/2023

Vaginal orifice
forms an
incomplete
partition called
hymen
hymen is quite
vascular and
tends to bleed
during first
coitus
 Types of
hymen
1/7/2023
170

171
 Mons pubis
 Rounded fatty elevation anterior to pubic
symphysis
 Consists of pad of fatty tissue
 After puberty this area is covered with pubic
hair
 Labia majora
 Two symmetrical hair covered, fatty skin folds
 Each passes posteriorly from mons pubis to
anterior of anus
 the female counterpart of the male scrotum
1/7/2023

…cnt
 Labia minora
 Thin, hair free folds of skin between labia
majora
 Enclose a recess called vestibule of vagina
and lie on each side of orifices of urethra and
vagina
 Meet superior to clitoris to form a fold of skin
called prepuce
 Posteriorly united by fold of skin called
frenulum of labia minora
 homologous to the ventral penis
1/7/2023
172

173 1/7/2023

174
 Vestibule of vagina
Space between labia minora
Urethra, vagina and ducts of vestibular
glands open into it.
External urethral orifice is posterior to
clitoris and anterior to vaginal orifice
Vaginal orifice lies posterior to urethral
orifice
Surrounded by thin fold of mucous
membrane called hymen
1/7/2023

…cnt
 Vestibular glands
The greater vestibular (Bartholin's)
glands
Flanking/on the side/ the vaginal opening
pea sized
release mucus into the vestibule to keep it
moist and lubricated, facilitating intercourse
 homologous to the bulbourethral glands of
males
open into the vestibule just below
the hymen. 1/7/2023
175

176
Clitoris
 composed of erectile tissue
 homologous to the penis
 not traversed by urethra
 located posterior to anterior labial commissure
 parts: root ,body & glans
 Has corpora cavernosa but it lacks corpus spongiosum
 parts of labia minora anterior to clitoris form prepuce
and posterior form frenulum
 richly innervated with sensory nerve endings sensitive
to touch, and it becomes swollen with blood and erect
during tactile stimulation,
contributing to a female’s sexual arousal
1/7/2023

177 1/7/2023

178 1/7/2023

Arteries of pelvis and perineum
179
 The major artery of the pelvis and perineum is
the internal iliac artery on each side
 Other vessels that originate in the abdomen and
contribute to the supply of pelvic structures
include
 median sacral artery
 ovarian arteries in women
1/7/2023

Internal iliac artery
180
 arise at intervertebral disc between L5 and
S1
 Enters the pelvis through greater sciatic
foramen
 divides into anterior and posterior trunks at
the level of the superior border of the
greater sciatic foramen
1/7/2023

181
Branches of the posterior trunk
 iliolumbar artery
 lateral sacral artery
 superior gluteal artery
 Iliolumbar artery
 climbing over the brim it ascends in front of the sacrum and
anastomoses with the lumbar arteries
 divides into lumbar branch and iliac branch
 lumbar branch
 contributes to the supply of the posterior abdominal wall, psoas,
quadratus lumborum muscles, and cauda equina via a small spinal
branch that passes through the intervertebral foramen between L5 and
S1
 iliac branch
 passes laterally into the iliac fossa to supply muscle and bone
1/7/2023

182
 Lateral sacral arteries
 usually two
 bone and soft tissues, structures in the
vertebral (sacral) canal, and skin and muscle
posterior to the sacrum
 Superior gluteal artery
 the largest branch
 muscles and skin in the gluteal region and also
supplies branches to adjacent muscles and
bones of the pelvic walls
1/7/2023

183 1/7/2023

184
Branches of the anterior trunk
 umbilical artery - gives origin to the superior
vesical artery
 superior vesical artery -
 obturator artery
 inferior vesical artery
 middle rectal artery
 uterine artery (in female)
 2 terminal branches
 internal pudendal artery
 inferior gluteal artery
1/7/2023

185
 Superior vesical artery
 superior aspect of the bladder and distal parts of the ureter
 ductus deferens
 Inferior vesical artery
 occurs in men and supplies branches to the bladder, ureter,
seminal vesicle, and prostate
 Vaginal artery
 adjacent parts of the bladder and rectum
 Middle rectal artery
 courses medially to supply the rectum
 anastomoses with the superior rectal artery, which originates from
the inferior mesenteric artery in the abdomen, and the inferior
rectal artery, which originates from the internal pudendal artery in
the perineum
1/7/2023

186
 Obturator artery
 leaves the pelvic cavity via the obturator canal
 together with the obturator nerve, above, and
obturator vein, below, it enters and supplies the
adductor region of the thigh
 Internal pudendal artery
 the main artery of the perineum
 among the structures it supplies are the erectile
tissues of the clitoris and the penis.
1/7/2023

187
 Inferior gluteal artery
 a large terminal branch
 supply of the gluteal region and anastomoses with a network of
vessels around the hip joint
 Uterine artery
1/7/2023

188 1/7/2023

189 1/7/2023

Veins
190
 Within the pelvic cavity, extensive interconnected
venous plexuses are associated with the surfaces
of the viscera (bladder, rectum, prostate, uterus,
and vagina)
 together, these plexuses form the pelvic plexus of
veins
1/7/2023

191
 part of venous plexus surrounding the rectum
and anal canal drains via superior rectal veins
(tributaries of inferior mesenteric veins) into the
hepatic portal system, and via middle and
inferior rectal veins into the caval system
 this pelvic plexus is an important portacaval shunt
when the hepatic portal system is blocked
1/7/2023

192  Deep dorsal vein
 single vein drains erectile tissues of the clitoris and the
penis
 does not follow branches of the internal pudendal
artery into the pelvic cavity
 instead, this vein passes directly into the pelvic cavity
through a gap formed between the arcuate pubic
ligament and the anterior margin of the perineal
membrane
 joins the prostatic plexus of veins in men and the
vesical (bladder) plexus of veins in women.
 Superficial veins that drain the skin of the penis and
corresponding regions of the clitoris drain into the
external pudendal veins, which are tributaries of the
1/7/2023

193
 Median sacral veins
 coalesce to form a single vein that joins either the
left common iliac vein or the junction of the two
common iliac veins to form the inferior vena cava
 Ovarian veins
 follow the course of the corresponding arteries
 on the left, they join the left renal vein and, on the
right, they join the inferior vena cava in the
abdomen
1/7/2023

194 1/7/2023

195 1/7/2023

vessels & nerves of
perineum
196
 pudendal nerve, internal pudendal artery and nerve to
obturator internus
 They cross the spine of ischium
 enter the perineum through the lesser sciatic foramen
 Internal pudendal artery and pudendal nerve
 They both give an inferior rectal branch
 Pass through ischiorectal fossa
 supplies the lower part of the anal canal and its muscles
 The inferior rectal nerve is sensory to the lower half of
the anal canal, motor to the sphincter ani externus and
levator ani. These muscles are also innervated by a
separate branch from S4.
1/7/2023

197
Pudendal nerve
 divides into a dorsal nerve of the penis (clitoris)
and the perineal nerve
 perineal artery
 gives rise to scrotal or labial branches;
 It supplies the bulb of the penis (clitoris) and the
urethra and ends by dividing into dorsal and deep
arteries of the penis
1/7/2023

Lymphatics of the abdomen and pelvis
198
 Lymph nodes are closely related to the main arteries
 Preaortic nodes
 related to the 3 ventral branches of the aorta
 All lymph vessels converge to form the intestinal
trunks leading to the cisterna chyli
 The preaortic nodes include the celiac, gastric,
pancreaticosplenic, hepatic, pyloric and gastroepiploic
(gastro-omental) nodes
 The liver drains mainly into the hepatic group. Part of
the upper surface drains into nodes around the inferior
vena cava and the left lobe drains into the left gastric
group.
1/7/2023

…cnt
 The pancreas drains into the pancreaticosplenic
nodes but also into the superior mesenteric nodes.
 The superior mesenteric and inferior mesenteric
nodes drain along the major arteries
 The lower part of the rectum and the upper part of the
anal canal drain along the middle rectal artery to
internal iliac nodes. The lower part of the anal canal
drains to inguinal nodes.
1/7/2023
199

200
Lateral aortic (Para aortic) nodes
 related to the lateral aortic branches
 The iliac nodes are classified into common, internal and
external
 Kidneys and suprarenal glands drain into the local lateral
aortic nodes
 The bladder, lower end of the ureter, ductus deferens
and seminal vesicles drain mainly to external iliac nodes
and partly to the internal iliac nodes.
 The prostate gland drains to internal iliac and sacral
nodes.
 The cervix of the uterus drains to external, internal iliac
and sacral nodes.
 The body of the uterus drains into external iliac nodes
and superiorly to lateral aortic and preaortic nodes.
 Retroaortic nodes lie posterior to the aorta
1/7/2023

201 1/7/2023

202
1/7/2023

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