Complete Review of Pevic Anatomy

By- Dr. Armaan SinghBy- Dr. Armaan Singh

Female Pelvis

Smout et al., 1969

Overview

Pubic Symphysis

Secondary cartilagenous joint

Articular surface of medial aspect of body of pubis

Covered with hyaline articular cartilage

Disc of fibro-cartilage in between

A cavity may develop in the disc but it is not lined with synovial membrane

There is normally very little movement at the pubic symphysis, except during the latter months of pregnancy

Sacroiliac Joint

Modified synovial plane joint

Articular surfaces are rough

The capsule is attached just beyond the articular margin

The interosseous sacroiliac ligament is one of the strongest ligaments in the body and is posterior to the joint

This articulation is almost immobile, except during pregnancy

• Sacrotuberous ligaments

• Sacrospinous ligaments

• Iliolumbar ligaments

• Posterior superior iliac spine is middle of the joint posteriorly at the level S2

• S2 is end of dura, arachnoid mater and subarachnoid space

• During gait, the amount of accessory movement at the sacroiliac joint helps to protect the lumbar intervertebral discs

Sacroiliac Joint Accessory Ligaments

Abnormalities of Pelvis

• Spina bifida occulta

• Unilateral lumbarisation

• Unilateral sacralisation

• Stress fractures of the sacrum, pubic arch and neck of femur may be first signs of osteoporosis

Walls of Pelvis

• Sacrum and coccyx posterior

• Os coxae below pelvic brim

• Piriformis covers middle three pieces of sacrum

• Passes out of the pelvis through the greater sciatic foramen

• Muscles

• Obturator internus muscle

• Origin of levator ani

• CoccygeusSmout et al., 1969

Obturator nerve

Obturator artery and vein

Parietal peritoneum supplied by the obturator nerve

Pain may be referred to hip or knee joints

Common iliac divides into external and internal iliac

Internal divides into anterior and posterior division branches

Smout et al., 1969

Lateral Walls of Pelvis

Pelvic Fascia

Pelvic fascia can be divided into three:

1. Pelvic wall

Pelvic fascia is a strong membrane over the piriformis and obturator internus

Fuses with the periosteum at their margins

2. Pelvic floor

Fascia is covered with loose areolar tissue

Loose areolar fat tissue lies in the extraperitoneal space between peritoneum and the viscera forming a dead space

Pelvic Fascia

3. Pelvic viscera • Fascia of pelvic viscera is loose or

dense depending on dispensability of organ

Smout et al., 1969

Pelvic Ligaments

Condensation around vessels form ligaments in the pelvis

Cardinal ligament condensation of fascia around uterine artery

Lateral ligament of the rectum is a condensation of fascia around the middle rectal vessels and branches of the hypogastric plexus

Waldyer’s fascia suspends the lower part of the ampulla of the rectum to the hollow of sacrum

Contains the superior rectal vessels and lymphaticsSmout et al., 1969

Pelvic Floor

Urogenital diaphragm

Perineal membrane and the superficial transverse perineii

The pelvic floor is a dome-shaped striated muscular sheet

The levator ani is made up mainly of the pubococcygeus, the puborectalis and the iliococcygeus

It encloses the bladder, uterus and rectum

Together with the anal sphincters, has an important role in regulating storage and evacuation of urine and stool

Stoker, 2009

Deep Perineal Pouch: Urogenital Diaphragm

Superior is the areolar tissue on the under surface of the levator ani

• The sphincter urethrae around urethra and transverse perineii in the deep pouch

• Perineal membrane fills in pubic arch below the muscles

• Muscles are supplied by perineal branch of pudendal nerve

• In lateral portion of the deep pouch, run dorsal nerve of clitoris and internal pudendal artery and vena commitans

superficial pouch

deep pouch

sphincter

urethrae

perineal

membrane

Levator Ani

• Arises, anteriorly, from the posterior surface of the body of pubis lateral to the symphysis

• Posterior from the inner surface of the spine of the ischium

• Between these two points, from a tendinous arch called the white line (arcus tendineus) adherent to the obturator fascia

Last,1984

Unites with the opposite side to form most of the floor of the pelvic cavity

The fibres pass downward and backward to the middle line of the floor of the pelvis

Inserted from before backwards, into perineal body

Side of the rectum and anal canal

Anococcygeal raphe

The side of the last two segments of the coccyxLast 1984

Levator Ani

The anterior fibres, pubovaginalis, pass behind the vagina, unites with the opposite side

Inserted into the perineal body, the central point of the perineum

Joining the fibres of the sphincter ani externus and transversus perineii

Last 1984

Levator Ani

Levator Ani

• The puborectalis forms a U-shaped sling, holding the anorectal anteriorly, blending with the deep fibres of the external anal sphincter

• Anococcygeal raphe lies between the coccyx and the margin of the anus

• Nerve supply, inferior rectal nerve and perineal branch fourth sacral

Last 1984

Levator Ani

In women, the levator muscles or their nerve supply, can be damaged in pregnancy or childbirth

There is some evidence that these muscles may also be damaged during a hysterectomy

Pelvic surgery using the "perineal approach" (between the anus and coccyx) is an established cause of damage to the pelvic floor. This surgery includes coccygectomy

Empty Female Bladder

• Bladder has a apex, triangular superior surface, base and two inferolateral surfaces, neck inferiorly

• Posterior or base is fixed, the two ureters enter obliquely at the junction of the superior surfaces and base

• The internal urethral orifice or neck is at the junction of the base and two inferolateral surfaces

• The interior of the bladder is lined with transitional epithelium which is thrown into folds in the empty bladder, except for the smooth triangular area of base called trigone

• Pubo vesical ligaments connect the neck to the pubic bone

• Base is attached to the supravaginal portion of the cervix and anterior fornix of vagina

• Peritoneum only covers superior surface

• Blood supply, superior and inferior vesical arteries

• Venous plexus into internal iliac vein

Female Bladder

Control of Micturition

• Smooth or detrusor muscle at the neck is the internal sphincter, supplied by the sympathetic

• Parasympathetic contracts detrusor muscle and relaxes internal sphincter

• Sphincter urethra or external sphincter is striated muscle

• Supplied by perineal branch of pudendal nerve S2,3,4,

Structure of Female Urethra

• Urethra 3-5 cm long

• Enters deep pouch where it is surrounded by

• Sphincter urethra, also called external sphincter of bladder

• Urethra pierces perineal membrane

• No fascia between lower two thirds of urethra and vagina

• Opens into vestibule, between clitoris and vagina

• Muscular layer continuous with bladder

• Spongy erectile tissue

• Plexus of veins

• Mucous membrane transitional

• Distal non keratinising stratified squamous

• Para urethral glands and ducts open into urethra, homologues of prostatic glands

Smout et al 1969

Urethra

Urethra

Urethra is supported by the fascia of the pelvic floor including pubo-vesical and pubocervical ligaments

If this support is insufficient, the urethra can move downwards

In times of increased abdominal pressure resulting in stress urinary incontinence (SUI)

The physical changes that can occur during pregnancy, delivery and menopause can predispose to SUI

Nuggaard and Heit in Bayliss 2010

Normal uterus is anteverted

i.e. anterior to vertical plane going through the vagina

Posterior fornix deeper

Anteflexed

Bent anteriorly junction of body and cervix

Pear-shaped muscular organ

8 cm long; 5 cm width; 3 cm thick

Non-pregnant state

Pelvic organ

Uterus

• Fundus

• Body

• Cervix opens into vault or fornices of vagina

• Fundus is the portion above entrance of uterine tubes

• Covered with peritoneum

• Body

• Triangular cavity

Uterus

• Isthmus is a circular borderline area between the body and cervix

• Isthmus is the supra vaginal portion of cervix, the lower uterine segment

• Intravaginal is surrounded by gutter by fornices of vagina,

• Posterior is deeper covered with peritoneum

• Internal os is the opening from the cavity of body

• Spindle shaped cavity cervix

• External os is the opening into vagina

Cervix

• Cervical canal is lined by columnar epithelium

• External os

• Junction of columnar of the cervical canal

• Stratified epithelium of the intravaginal portion

• Site of cancer of cervix

• Cervical smear

• At birth cervix is larger than the body

• Fully developed

• Cervix is one third of body

Cervix

Supports of Uterus

• Upper

• Round ligament

• Broad ligament anteverted

• Transverse ligament

• Pubocervical

• Uterosacral

• Lower

• Levator ani, coccygeus

• Perineal body

Round Ligament

• Round ligament and ligament of ovary

• Develop from the gubernaculum

• Side of uterus, junction fundus and body

• Inguinal canal to labium majus

• Ante version

Pubocervical Ligament

Attached

Anteriorly to posterior aspect of body of body of pubis

Passes to neck of bladder

Anterior fornix of vagina

Pubocervical ligaments help to

Maintain normal angle of 45° between the vagina and horizontal

Decrease may cause a cystocoele

Transverse Ligament

Transverse or cardinal or Mackenrodt’s ligament

Thickening of visceral layer of pelvic fascia around uterine artery

Lateral to medial in base of broad ligament

Uterosacral Ligament

Uterosacral contains fibrous tissue

Non-striated muscle

Attached from the cervix to the middle of sacrum

Contains lymphatics draining cervix to sacral glands

Uterosacral help to keep uterus anteverted

If uterus is anteverted it cannot prolapse

Blood Supply

• Uterine from internal iliac

• Ovarian from aorta at L2

• Vaginal arteries from internal iliac

• Anterior and posterior arcuate run in middle layer

Serous layer

Myometrium

No submucous layer

Endometrium

Compact at surface of uterine cavity and spongy layer are supplied by spiral arteries

Basal layer is not shed during menstruation; supplied by radial branches

Veins below artery

Plexus in lower edge broad ligament into internal iliac

Blood Supply

Embolization of Fibroids

• Fibroids vary in size and position in uterine wall

• May enlarge and compress ureters or other structures in pelvis

• A small catheter is inserted in the groin, into the femoral artery

• Small particles are introduced through the catheter into the uterine artery

• They block the blood supply to the fibroids

• The fibroids thus starved of blood shrivel and die over the next few months

Lymphatics of Uterus and Vagina

Nerve Supply of Uterus

• Pain from cervix via parasympathetic S2,3

• Pain from body via sympathetic to T11 and T12

Broad Ligament

• Fold of peritoneum from side of uterus to side wall of pelvis

• Framework of pelvic fascia

• Parametric fat

• Anterior surface looks inferiorly

• Free upper border

• Base lies on pelvic floor

• Uterine tubes

• Ovarian vessels

• Uterine vessels

• Epoophoron

• Paroophoron

• Round ligament of uterus and ligament of ovary

• Transverse ligament

• Ovary attached to posterior layer

• Ureter in base below uterine artery

Contents of Broad Ligament

Uterine tube lies in medial four fifths of free border of broad ligament

Lateral one fifth

Contains ovarian vessels

Infundibulo-pelvic or suspensory ligament of ovary

Epoophoron

Parallel tubules remains of mesonephric tubules

Gartner's duct remains of mesonephric duct, may form cysts

Broad Ligament

Broad Ligament

Uterine Tube

• Intramural

• Isthmus

• Ampulla

• Infundibulum surrounded by fimbria

• Lined ciliated columnar epithelium

• Beats towards uterus

Peritoneum loosely attached to ampulla

• Tightly to isthmus, if ectopic implanted here, ruptures earlier

• Fimbria surrounding opening into peritoneal cavity

• Ovarian fimbria is longest

Ovary

• Attached to posterior layer of broad ligament meso ovarian

• Covered with germinal epithelium

• Related to side wall of pelvis which is covered with peritoneum

• Obturator internus muscle

• Obturator nerve supplies the parietal peritoneum

• Posterior to ovary is the ureter

• Ligament of ovary medially

• Obturator nerve supplies the parietal peritoneum

• Irritation of the peritoneum of the side wall by bleeding at ovulation or by lesions involving the ovary

• May result in referred pain to medial side of the thigh or the knee

Ovary

Blood supply

One ovarian artery from lateral aspects of aorta L2

Right vein drains into inferior vena cava

Left drains into left renal vein

Lymphatics into para aortic glands L2

Ovary

Vagina

Fornices, gutters which surround the cervix

Normal anteverted antiflexed

Anterior fornix is shallow anterior wall is shorter than posterior

Posterior deeper, covered with peritoneum of the pouch of Douglas

Most dependent part of peritoneal cavity

Walls in contact except superior

Opens into vestibule of vagina

Uterine Artery

• Uterine artery lies superior to the ureter at lateral fornix of vagina

• Base of broad ligament

• Erectile tissue

• Muscular wall

• Pelvic fascia

• Nonkeratinised stratified squamous epithelium

• Urethra lower third anterior wall

• No fascia between lower two thirds of urethra and vagina

• Upper portion of the vagina is clasped by the pubo-vaginalis portion of the levator ani

Vagina

Deep pouch

Sphincter urethrae, deep transverse perineii, pierces perineal membrane, opens into vestibule of vagina

Hymen fold of mucous membrane at external opening

Lateral are the bulbs of vestibule

Covered by bulbospongiosus muscle

Greater vestibular (Bartholin's) glands lie behind the bulbs of vestibule

Ducts open into orifice of the vagina

Posterior to vagina is the perineal body

deep pouch

superficial

Vagina

Perineum

perineal body central

point of perineum

Peritoneum on Uterus and Vagina

• Reflected from the superior surface of the bladder

• Junction of the supravaginal portion of the cervix and the body of the uterus forming the utero vesical pouch

• Peritoneum then covers body, fundus and posterior surface body and then the supravaginal cervix and posterior fornix of vagina

• Peritoneum then reflected on to junction of upper two thirds and lower third of rectum forming

• Pouch of Douglas is most dependent part of female peritoneal cavity

Blood and Nerve Supply Vagina

• Uterine artery

• Vaginal

• Internal pudendal

• Labial

• Ilio Inguinal nerve supplies the anterior wall

• Labial nerves supply the posterior wall

Lymphatics of Vagina

• Internal iliac

• Lower third

• Medial group of proximal superficial inguinal glands

Pelvic Plexus

• Lumbar splanchnics L1-L2

• Presacral nerve

• Anterior to body of L5

• Divide into pelvic plexuses

• Postganglionic of sympathetic that relayed in lumbar and sacral ganglia causes contraction of sphincters of bladder and anal canal

Pelvic Parasympathetic

• Preganglionic have cell bodies in lateral column of segments S2,3,4

• Ganglia found close to or in wall of organ

• Supplies intestine from splenic flexure to upper two thirds of anal canal, bladder

• Motor to walls and inhibitory to sphincters

• Parasympathetic causes erection

Rectum

• Rectum is a continuation of pelvic colon

• Starts at the third piece of the sacrum

• Ends 5 cm from the tip of coccyx

• Lower end is dilated at the ampulla, at the anorectal junction

• There are no taeniae and no appendices epiplociae on the rectum

It has an antero-posterior curve, above it is angled anteriorly by the puborectalis

Below convex forwards

Three lateral curves

Two concave to left, one to right, where the valves of Houston, which consist of circular muscle and mucous membrane

Peritoneum covers upper third on front and sides

Middle third on front, none on lower third

Rectum

Blood Supply of Rectum Superior rectal, continuation of inferior

mesenteric artery

Runs in Waldyer’s fascia from hollow of sacrum to the lower part of the ampulla of the rectum

Supplies mucous membrane as far mucocutaneous junction of anal canal

Venous drainage into portal system

Middle rectal the muscle layer

Small twigs from median sacral

Anal Canal

• Starts at anorectal junction

• Below ampulla of rectum

• Passes backwards

• Approx 4 cm

• Ends at anus

• Anterior: perineal body

• Posterior: anococcygeal body

• Lateral: ischiorectal fossae

Muscles of Anal Canal

The anal sphincter is a multilayered cylindrical structure

The inner smooth muscle of the internal sphincter

Surrounds upper two thirds

Lower two thirds the outer striated muscle layer of the external sphincter

Anorectal ring formed by puborectalis and the deep part of the external sphincter

Peri Anal Fascia

Perianal fascia continuation of longitudinal coat of rectum

Medial to deep and superficial external sphincters

Attached at Hilton’s line

Passes to lateral wall

Above subcutaneous sphincter

Lateral sheet passes between soft ischiorectal fat and subcutaneous fat to lateral wall

Splits to form pudendal canal and is

Continuous superiorly with the lunate fascia, which passes above soft ischiorectal fat

It is medial to deep and superficial sphincter

Above subcutaneous sphincter

Anal Canal

Puborectalis portion levator ani holds the anorectal junction anteriorly

Deep and subcutaneous parts of external are true sphincters

No bony attachments

Superficial attached to coccyx and the perineal body

Muscles of Anal Canal

Anorectal ring

Internal sphincter

Puborectalis

Puborectal fascia

External sphincter

Deep, true sphincter, no bony attachments

Inferior rectal nerve S3,4

Superficial S4

Subcutaneous, true sphincter

Inferior rectal nerve S3,4

Muscles of Anal Canal

Upper two thirds lined by

columnar epithelium

Lower third by skin

Junction of two is Hilton’s white line skin

Anal columns contain radicles of superior rectal artery and veins 4,7,11

At the lower end joining the columns are mucosal folds called anal valves

Anal sinuses lie behind

Skin supplied by inferior rectal vessels and nerves

Anal Canal

Blood and Nerve Supply

• Upper two thirds

• Columnar epithelium

• Superior rectal artery

• Autonomic nerves

• Derived from cloacae

• Lower third

• Skin

• Inferior rectal S3,4,

• Somatic nerves

• Derived from proctodeum

Venous Drainage

Mucosa upper two thirds

Superior rectal vein

Portal system

Lower third

Inferior rectal vein

Vein into systemic system

Portal systemic anastomosis’ 4,7,11

Lymphatic Drainage

Upper third

Pre aortic inferior mesenteric

Waldeyer’s fascia passes from sacrum to the ampulla of rectum

Encloses superior rectal vessels and lymphatics

Internal iliac

Lower Third

Inferior rectal cross ischio-rectal fossa

Medial superficial inguinal glands

Anal Sphincters

• The internal and external anal sphincters are primarily responsible for maintaining faecal continence at rest and when continence is threatened, respectively.

• Defecation is a somato-visceral reflex regulated by dual nerve supply (i.e. somatic and autonomic) to the anorectum.

Bharucha 2006

Anal Sphincters

• The net effects of sympathetic and cholinergic stimulation are to increase and reduce anal resting pressure, respectively.

• Faecal incontinence and functional defecatory disorders may result from structural changes and/or functional disturbances in the mechanisms of faecal continence and defecation.

Bharucha 2006

Ischiorectal Fossa

Ischiorectal fossa contents

Soft ischiorectal fat

Lunate fascia above the fat

Inferior rectal vessels pass above the fat to reach medial wall

Perineal branch of S4

ischiorectal fossa

Ischiorectal fossa contents

lunate fascia above the soft ischiorectal fat

Inferior rectal vessels and nerve pass above lunate fascia and the fat to reach medial wall

Subcutaneous fat lies below perianal fascia

Perineal branch of S4

Lymphatics cross fossa

Ischiorectal Fossa

Pudendal Canal

• Runs posterior to anterior

• Pudendal canal contents

• Pudendal nerve

• Inferior rectal nerve

• Dorsal nerve of clitoris

• Perineal nerve

• Labial nerves

• Internal pudendal vessels

Pudendal Block

Pudendal nerve

Lies on the sacrospinous ligament

Anaesthetizes posterior wall of the vagina

Ilioinguinal nerve supplies the anterior wall

Age, pregnancy, family history, and hormonal status all contribute to the development of pelvic organ prolapse. The vagina is suspended by attachments to the perineum, pelvic side wall and sacrum via attachments that include collagen, elastin, and smooth muscle. Surgery can be performed to repair pelvic floor muscles. The pelvic floor muscles can be strengthened with Kegel exercises.

Disorders of the posterior pelvic floor include rectal prolapse, rectocele, perineal hernia, and a number of functional disorders including anismus. Constipation due to any of these disorders is called "functional constipation" and is identifiable by clinical diagnostic criteria.