Pelvic Floor & Perineum

Question 1

Bony Pelvis Landmarks & Measurements

Answer 1

o True pelvis – deep to the pelvic inlet
o False pelvis – superior to pelvic inlet
o Conjugal (AP) Diameter – fixed distance; from sacral body to pubic symphysis (>11cm)
o Pelvic Outlet – distance between ischial spines (>10cm)

Question 2

Pudendal Nerve & Clinical Correlation

Answer 2

-(ventral rami S2-S4) – passes behind ischial spine to enter perineum
o Supplies entire perineum (skin of external genitalia, muscles, and other areas)
o Clinical Correlation: Pudendal Block
 Used for vaginal deliveries and minor surgeries of vagina and perineum
 Injection where pudendal nerve crosses behind the ischial spine (palpable)
 Transvaginal (more reliable & more common) or transcutaneous (perineal) approach

Question 3

Variations in Male & Female Pelvis

Answer 3

Male (android pelvis)
	Thick and heavy
	Subpubic angle 90 degrees
	Pelvic inlet – rounded
	Pelvic outlet – large
	Ischial spines do not protrude inward

Question 4

Pelvic Floor

Answer 4

(pelvic diaphragm, levator ani) – muscular diaphragm which supports pelvic viscera
o Puborectalis muscle – slight contraction responsible for right angle between rectum & anal canal
 Relaxation of muscle when pooping gets rid of angle and allows poop to come out
o Sphincter of vagina – contracts during female orgasm
o Works with abdominal diaphragm to increase intra-abdominal pressure by raising pelvic floor
o Prevents downward displacement during coughs and forced expiration

Question 5

Pelvic Floor Injury

Answer 5

o Muscles may be injured during childbirth
o Weakness of muscles may alter position of bladder neck or urethra  urinary stress incontinence
 (Kegel) exercise after childbirth who were leaking urine due to weakened muscles
 Kegel muscles include pelvic floor muscles and other muscles of perineum

Question 6

Pelvic Floor Take Home Message

Answer 6

o Differences between male & female are used in forensic medicine
o Pelvic factures common – often involve soft tissue injury
 Anteroposterior compression in auto accidents
 Falls may drive femoral head through floor of acetabulum
o Pregnancy – joints & ligaments relax (sex hormones, relaxin) ~15% increase in diameter
o Pelvic inlet & outlet may be barriers to normal delivery
o Conjugate (AP) diagonal (>11cm) is fixed distance at pelvic inlet which babies head must pass through in vaginal delivery; distance between ischial spines at pelvic outlet >10cm
o Sacroiliac ligaments are among strongest in body and the cause of lower back pain
o Pudendal block***

Question 7

Perineum

Answer 7

– superficial to the perineal floor
o Diamond shaped space bound anteriorly by pubic symphysis, laterally by ischial tuberosity, and posteriorly b sacrum
o Imaginary line between ischial tuberosities divides perineum into 2 triangles
 Urogenital – urogenital diaphragm with urethra and vaginal openings – located between the pubic bones
 Anal – contains anal canal and 2 ischioanal fossas (allow anus to expand when pooping)

Question 8

3 Layers in Perineum Below the Pelvic Floor Muscles

Answer 8

o Superficial fascia of Urogenital diaphragm
o Urogenital diaphragm and muscles including external urethral sphincter
o Inferior fascia of urogenital diaphragm (perineal membrane)
o Roots of external genitalia (penis and clitoris)
o Skin and superficial fascia

Question 9

Roots of External Genitalia

Answer 9

 Includes muscles
• Superficial transverse perineal muscle
• Ischiocavernosus – surrounds the crura
• Bulbospongiosus – surrounds the bulb
 Includes erectile tissue – 2 crura (against pubic rami) & bulb fill with blood and harden
• Male – 2 crura and bulb come together to form penis
• Female – 2 crura come together to form clitoris; bulb NOT involved

Question 10

Male Contents of Deep Pouch

Answer 10

(above perineal membrane between superior and inferior fascias of the urogenital diaphragm) – urogenital diaphragm (urethra sphincter muscles), membranous part of urethra, bulbourethral gland

Question 11

Male Contents of Superficial Pouch

Answer 11

(below perineal membrane)– erectile structures that form penis (bulb and crura); proximal part of spongy urethra

Question 12

Male Perineum Clinical Notes

Answer 12

o Urethral rupture can occur after blow to perineum; urine may flow into superficial perineal space
o Scrotum may be easily distended from a hernia or fluid production (orchitis) or bleeding
o Testes can be easily palpated due to thin wall of scrotum
o Palpation of testes and epididymis is important in the differential diagnosis between testicular cancer or inflammation of the epididymis
o Bulbourethral glands (cowper’s gland) – located between the 2 layers of urogenital diaphragm fascia, in the deep perineal pouch
 Homologous to Bartholin’s (great vestibular) glands in female

Question 13

Episiotomy

Answer 13

– surgical incision of perineum and posterior vaginal wall during labor
o Either median or mediolateral (avoids anal sphincter) incision
o Benefits – speeds up birth, prevents tearing, protects against incontinence, heals easier than tears
o Costs – infection, ↑ pain, longer healing times, increased discomfort when intercourse resumes

Question 14

Female Contents of Deep Pouch

Answer 14

urogenital diaphragm (urethra sphincter muscle), urethra, vagina

Question 15

Female Contents of Superficial Pouch

Answer 15

– erectile structures of clitoris (bulb/crura), Bartholin’s glands

Question 16

Female Perineum Clinical Notes

Answer 16

o Perineal body is fibromuscular region between vaginal and anal canals; 8 muscles joint at PB
o Integrity of perineal body is important after childbirth; tearing may lead to prolapse of bladder, uterus, or vagina
o Perineal body also disrupted by trauma, inflammatory disease, and infection
o Numerous glands and ducts open onto surface making the area more prone to infections
o Bartholin’s glands (greater vestibular glands) in superficial perineal pouch
 Bartholin’s cysts are more common in women aged 20-29; develops 2% of all women

Question 17

Perineum Take Home Message

Answer 17

o Urogenital Diaphram suspends the roots of the penis and clitoris with clitoris lying below
o Perineal region is composed of 2 pouches: superficial and deep perineal pouches

Question 18

Blood Supply & Ureter Location

Answer 18

o	Aorta branches at L4 into common iliac and then external and internal iliac arteries
o	External iliac-becomes femoral artery in the thigh
o	Internal iliac Arteries
Posterior division
•	Iliolumbar
•	Lateral sacral
•	Superior gluteal
Anterior division
•	Vesicular – goes to bladdery
•	Umbilical
•	Superior vesicle
•	Inferior vesicle (vaginal) – goes to vagina
•	Middle rectal
•	Obturator
•	Internal pudendal
•	Inferior gluteal
•	Uterine 
o	Ureter passes under the uterine artery (“water under the bridge”)

Question 19

Lymph Drainage

Answer 19

o Testes and ovaries drain to aortic nodes because they receive bloody supply from aorta
o Organs supplies by common/external/internal iliac vessels drain to iliac nodes
o Superficial inguinal nodes in groin inferior to inguinal ligament
o Path: superficial inguinal nodes  saphenous opening  deep inguinal nodes  femoral canal  external iliac nodes  common iliac nodes  aortic nodes

Question 20

Nerves of Sacral Plexus

Answer 20

Sacral Plexus – L4 to S4
o	Lumbosacral trunk – L4 and L5
o	Sciatic – L4-S4
o	Posterior femoral cutaneous
o	Pudendal – S2 – S4

Question 21

Bladder and Urethra (male) + Utero-vesicular pouch

Answer 21

o Anterior: pubic bone
o Superior: peritoneum and small intestine
o Posterior: rectum, vas deferens, and seminal vesicles
o Blood: internal iliac
o Lymph: internal iliac nodes
o Urethra = 8 inches long
 Prostatic = 1 inch; receives 2 ejaculatory and 20 prostatic ducts
 Membranous = 1 inch long and crosses urogenital diaphragm (external urethral sphincter)
 Spongy = 6 inches long; part of it lies under the pubic bone and prone to injury
o Bladder – neck of bladder has involuntary internal sphincter that contracts during ejaculation to prevent retrograde ejaculation of semen into bladder
o Women – utero-vesicular pouch – fold in peritoneum that separates the uterus from the bladder

Question 22

Foley Catheter

Answer 22

o Balloon at end of tip that will prevent urine from leaving bladder and force it into tube
o Male – more difficult to insert due to S shaped urethra

Question 23

Suprapubic Cystotomy

Answer 23

– needle’s used to drain the bladder when flow is obstructed
o When bladder is full it rises up into abdomen
o Insert needle just superior to the pubic symphysis
o Needle travels through skin, linea alba, traversalus fascia, space of Retzius and the bladder

Question 24

Clinical Notes: Bladder and Urethra

Answer 24

o Urethra & bladder infections more common in women: shorter urethra = more distensible
o Full bladder may extend up into anterior abdominal wall just above pubic bone; peritoneum is peeled off anterior body wall as bladder becomes intra-abdominal – no danger of peritonitis
o Transurethral resection of a bladder tumor is often performed using a cystoscope
o In transurethral resection of prostate (TURP), an instrument is inserted up the urethra to remove the section of prostate that is blocking urine flow
o Male urethra can be crushed against pubic bone; female rupture is rare because of short length
o Loss of bladder support in females by damage to perineal muscles during delivery is common; there could be herniation of the bladder into the vaginal wall (called cystocele)

Question 25

Vagina

Answer 25

o Fornix – form a continuous gutter around the cervix/vagina/external os
 Posterior fornix, if penetrated would rupture the rectal-uterine pouch (pouch of Douglas) and lead to rupture in peritoneum  peritonitis
 Lateral fornix is in close proximity to the ureter; some vaginal cancers spread to ureter
o Blood Supply: vaginal branch of internal iliac artery
o Lymph: upper 2/3 drains into internal iliac; lower 1/3 drains into superficial inguinal nodes
 Pelvic part  iliac nodes; perineal part  superficial inguinal nodes

Question 26

Clinical Notes: Vagina

Answer 26

o Vaginitis common; symptoms include itching, burning, pain, abnormal bleeding, discharge
o Neoplasm in pouch of Douglas felt with finger in exam; rectal neoplasm can invade vagina
o During abortions, inexperienced gynecologist push non-sterile instrument into posterior fornix & through vaginal wall into peritoneal cavity  peritonitis and death may result
o In old people, vagina shrinks and fornices almost disappear
o Interior vagina and vaginal part of cervix can be examined with a vaginal speculum
o Surgical procedures on vagina are relatively common
o Vagina can be easily distended, especially by the fetus during pregnancy; cystocele also occurs

Question 27

Uterus

Answer 27

o Uterine cavity is triangle in coronal section
o utero-vesicular pouch lies anterior
o recto-uterine pouch (pouch of Douglas) lies posterior and extends down to top ¼ of vagina
o Lateral cornu fundus  body  isthmus  internal os  cervical canal  external os
o Laterally – broad ligament, ureter, uterine artery/vein, uterine tubes, round ligament of uterus, ligament of ovary
 Ureter may be compressed by overgrowth of uterus leading to kidney disease
o Blood: uterine artery and ovarian artery
o Lymph: fundus  para-aortic nodes
 Lateral cornu superficial inguinal nodes
 Body  iliac nodes

Question 28

Support for Uterus

Answer 28

-Connective tissue just above pelvic floor muscles supports the cervix of uterus and upper vagina
 Cardinal (Mackenrodt’s) ligament – lies over the pelvic floor above the perineum and wraps around the cervix
 Broad ligament (enclosing uterine tube) is double fold of peritoneum connecting the lateral margin of uterus to side wall of pelvis
• Uterus and broad ligament form a partition in pelvis
• Anterior compartment contains bladder; Posterior compartment contains rectum
 Round ligament - passes from side of uterus through deep inguinal ring to labia majora
• Round ligament stretches during pregnancy  “ligament pain”

Question 29

Clinical Notes: Uterus (Hysterectomy/cervicectomy/fibroids)

Answer 29

o Hysterectomy – the ureter may be accidentally divided when clamping the uterine vessels
 Ureter lies just next to lateral fornix
o Ureter may be compressed by a growth from uterus or cervix leading to kidney disease
o Non-pregnant cervix has consistency of a nose; pregnant cervix has soft consistency of lips
o Damage to levator ani and ligaments may lead to downward displacement of uterus (“uterine prolapse”); common after menopause
o Cervical cancer is 3rd gynecologic malignancy worldwide and disease with a predilection for young women; 30% of women with cervical cancer are less than 35yo
 Endometrial cancer is most common gynecological malignancy; then ovarian cancer
o Cervicectomy – conservative procedure for early carcinoma of cervix; cervix and upper vagina are resected; body of uterus is anastomosed to remainder of vagina and fertility is maintained
o Fibroids – benign tumors of uterus that are common and cause heavy menstrual bleeding
 Appear during childbearing years
 75%of women have uterine fibroid during lifetime; most are symptomatic
 Uterine artery embolization – treatment of intractable menorrhagia for uterine fibroids

Question 30

Uterine Tube

Answer 30

(aka oviduct, fallopian tube)
o 10 cm long and lies in upper border of broad ligament; 4 parts
 Infundibulum – extends beyond broad ligament; opens into peritoneal cavity; fimbria
 Ampulla – wide and thin-walled; where fertilization takes place
 Isthmus – narrow and thick-walled;
 Intramural – part opening into uterus
o Blood Supply: uterine and ovarian arteries
o Lymph: internal iliac and para-aortic nodes

Question 31

Clinical Notes: Uterine Tube

Answer 31

o Communication w/ peritoneal cavity is pathway for infection (pelvic inflammatory disease)
o Fertilization Tubal ligation is common method of birth control
o Major cause of infertility is blockage of uterine tube caused by infection (salpingitis)
o Ectopic pregnancy is implantation of embryo in uterine tube
 1 in 250 pregnancy are ectopic  rupture of uterine tube and life threatening to mother
o Laparoscopy – used to examine uterus, ovaries, and uterine tubes, and diagnose pelvic diseases
o Ruptured tubal pregnancy can be misdiagnosed as appendicitis due to close proximity and both cause referred pain to the right lower quadrant
o Patency of tubes is determined by hysterosalpingogram
 Insert catheter into vagina; contrast is injected and images are taken to view uterus
 Anomalies can be seen such as unicornuate uterus – uterus is formed from only on of the paired Mullerian ducts often results in miscarriages

Question 32

Ovary

Answer 32

o Blood: ovarian artery – enters from within suspensory ligament of ovary
 Ovarian vein
• Left  goes to renal vein
• Right  goes to inferior vena cava
o Lymph: para-aortic nodes  reason why ovarian cancer is so deadly
o Shrinks after menopause
o Kept in place by broad ligament and mesentery that attaches ovary to broad ligament

Question 33

Opsoclonus-Myoclonus Syndrome

Answer 33

– “Dancing eyes and Dancing feet”
o Myoclonus – jerking body movements
o Opsoclonus – rapid, involuntary eye movements
o Most common germ cell tumor (teratoma)  resulting in ovarian mass

Question 34

Clinical Notes: Ovary

Answer 34

o Position of ovary is variable; can even be found in pouch of Douglas
o Appendix may lie very close to it on the right side
o During pregnancy – ovary and broad ligament are moved superiorly
o After pregnancy – ovaries often do not return to original position

Question 35

Lymph Drainage of Female Pelvis

Answer 35

o Iliac nodes – upper 2/3 vagina; most of uterus; bladder; urethra
o Superficial Inguinal Nodes – lower 1/3 vagina; part of upper uterus via round ligament; urethra
o Para-aortic nodes – fundus of uterus; ovaries; uterine tubes

Question 36

Prostate

Answer 36

o Superior: bladder
o Inferior: rests on urogenital diaphragm
o Posterior: rectum

Question 37

3 Ways of Prostate Cancer Spreading

Answer 37

 Invasion of adjacent organs by cancer
 Spread via venous drainage – connections between prostatic and vertebral venous plexus cancer can easily spread to brain via valveless vertebral veins
 Spread through lymph channels to internal iliac and obturator lymph nodes

Question 38

3 Surgical Approaches to Prostate

Answer 38

 Suprapubic approach
 Perineal approach
 Transurethral approach  results in urethra also being taken out and catheter is left in place until a new urethra is formed around catheter and functions after catheter removal

Question 39

Prostate Cancer

Answer 39

o Prevalence of prostate cancer and its posterior relationship
 Rectal exam for men over 40 to determine enlargement of prostate
 ALL MEN over 50 experience enlargement of prostate (benign prostatic hyperplasia)
 May cause abnormal/nocturia urination due to distorting the prostatic urethra
o Prostate cancer usually causes death via renal failure  invades ureter and blocks kidney

Question 40

Seminal Vesicles + Ductus Deferens

Answer 40

– 2 inches long; lobulated sacs; posterior/superior to prostate; anterior to rectum
o May be felt in rectal exam but only if enlarged
- ductus deferens - 18 inches long

Question 41

Clinical Notes: Ductus (vas) deferens and Seminal Vesicles

Answer 41

o Epididymitis – infection that traveled from urethra through vas Deferens and into epididymis
o Orchitis – infection that travels to testis
o Vasectomy – division of vas Deferens; ejaculated fluid contains no sperm
 Can be reversed (vasovasostomy) in some cases (after 7 years, no longer fertile due to lack of germ cells)
 Leads to thickened basement membrane and lack of spermatogenesis
o Abscesses in seminal vesicles may rupture allowing pus to enter the peritoneal cavity