82 terms

GA - Perineum

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Perineum contains
external genitalia
external opening of urogenital system
external opening of gastrointestinal system
Boundaries of perineum (5)
Pubic symphysis
Ischiopubic rami
Ischial tuberosities
Sacrotuberous ligaments
Coccyx
Anal triangle faces
posteroinferiorly
Urogenital triangle faces
horizontally
Layers of the urogenital triangle (6)
Skin
Superficial perineal fascia - fatty & membranous
Inferior fascia of the urogenital diaphragm
Urogenital diaphragm
Superior fascia of urogenital diaphragm
The fatty layer of superficial perineal fascia is continuous with
Camper's fascia
Membranous layer of superficial perineal fascia, aka
Colles' fascia
In males, Colles' fascia is continuous with
superficial penile fascia
Dartos fascia
Scarpa's fascia
Inferior fascia of the urogenital diaphragm, aka
perineal membrane
Superficial perineal space is found between
Colles' fascia
Inferior fascia of the urogenital diaphragm
Deep perineal space is found between
Superior fascia of the urogenital diaphragm
Inferior fascia of the urogenital diaphragm
Contents of superficial perineal space (male) (6)
Root of penis & proximal spongy urethra
Bulbospongiosus
Ischiocavernosus
Superficial transverse perineal muscles
Branches of internal pudendal artery & vein
Perineal branch of pudendal nerve
Root of the penis (definition)
Attached part formed by two crura and bulb
Crura of penis (definition)
proximal parts of corpora cavernosa
Bulb of penis (definition)
proximal part of corpus spongiosum
contains spongy portion of urethra
Body of penis (definition)
shaft
Glans penis (definition)
head
Body of the penis formed by
two fused corpora cavernosa and corpus spongiosum
Deep artery of the penis is found in
corpus cavernosum
Spongy urethra is found in
corpus spongiosum
Coverings of the body of the penis (3)
Skin
Superficial fascia
Deep fascia (Buck's)
Superficial dorsal vein of penis is found in
superficial fascia
Deep dorsal vein, artery, nerve are found
deep to the deep fascia of the penis
Muscles found in superficial perineal pouch (male) (3)
Ischiocavernosus m.
Bulbospongiosus m.
Superficial transverse perineal m.
Ischiocavernosus muscle covers (male)
the crura of the penis
Bulbospongiosus muscle covers (male)
bulb of the penis
proximal corpus spongiosum
Contents of superifical perineal space (female) (9)
Clitoris
Bulb of the vestibule
Greater vestibular (Bartholin's) glands
Bulbospongiosus
Ischiocavernosus
Superficial transverse perineal muscles
Part of urethra
Branches of internal pudendal artery & vein
Perineal branch of pudendal nerve
Crura / roots of the clitoris (definition)
Proximal attached parts of corpora cavernosa
Body of the clitoris (definition)
Unattached part that ends in glands
Bulbs of vestibule correspond to what in the male?
proximal part of corpus spongiosum
Bartholin's glands are important because
they are a site of infection, inflammation, or cancer
Ischiocavernosus muscle covers (female)
crura of the clitoris
Bulbospongiosus muscle covers (female)
bulbs of the vestibule
Superficial and deep perineal spaces separated by
perineal membrane
Passive support to pelvic structures supplied by
perineal membrane
inferior fascia of urogenital diaphragm
External genitalia attached to
inferior surface of perineal membrane
Contents of deep perineal space (male) (5)
Membranous urethra
Urogenital diaphragm
Branches of internal pudendal artery & vein
Dorsal nerve of penis
Bulbourethral / Cowper's glands
Muscles of the deep perineal pouch (male) (3)
External urethral sphincter
Deep transverse perineal membrane
Bulbourethral glands
Contents of the deep perineal space (female) (5)
Urethra
Vagina
Urogenital diaphragm
Branches of internal pudendal artery & vein
Dorsal nerve of the clitoris
Urogenital diaphragm consists of (female) (4)
External urethral sphincter
Deep transverse perineal muscle
Sphincter urethrovaginalis
Compressor urethrae
Muscles of deep perineal pouch (female) (4)
External urethral sphincter
Deep transverse perineal muscle
Sphincter urethrovaginalis
Compressor urethrae
Vaginismus
Spasm of urethrovaginalis causing difficulty during pelvic exam or intercourse
Perineal body in females is what in males?
Central tendon of perineum
Muscles of perineal body / central tendon of perineum (6)
Bulbospongiosus
External anal sphincter
Superficial and deep transverse perineal muscles
External urethral sphincter
Levator ani
Rectal wall
What is the function of the perineal body?
To provide support for pelvic viscera; if torn/overstretched during childbirth → uterus, bladder, or rectum may sag into the vagina (prolapsee*).
Episiotomy (definition)
Incision of perineal body in females to prevent jagged tears during childbirth
Anal triangle contains
Anal canal
Ischioanal fossae
Anal canal begins at
anorectal junction (perineal flexure) where the puborectalis portion of levator ani muscle forms a sling around the digestive tube
What is the clinical significance of the ischioanal (ischiorectal) fossae on either side of the anal canal?
An infection in one ishioanal fossa may spread behind the anal canal and into the other ischioanal fossa; can result from inflammation, tear in anal mucous membrane, or a penetrating wound in the anal region.
Anal canal divided by
pectinate line
Anal canal above pectinate line derived from
hindgut
Anal canal below pectinate line derived from
proctodeum (ectodermal depression)
Pectinate line, aka
dentate line
mucocutaneous line
Above pectinate line, anal canal is innervated by
Sensory: GVA fibers traveling with parasympathetic fibers to S2-S4 dorsal ganglia
Motor: inferior hypogastric plexus
Above pectinate line, anal canal receives & drains blood from
superior rectal artery
superior rectal vein (portal venous system)
Above pectinate line, lymph is drained to
inferior mesenteric lymph nodes
Below pectinate line, anal canal is innervated by
Sensory: GSA fibers
Motor: inferior rectal nerves (from pudendal n.)
Below pectinate line, anal canal receives blood from
middle rectal artery / vein (internal iliac artery / vein)
inferior rectal artery / vein (internal pudendal artery / IVC)
Below pectinate line, lymph is drained to
superficial inguinal lymph nodes
Hemorrhoids
Enlarged submucosal rectal veins
Internal: superior rectal veins above pectinate line; GVA fibers = painless
External: inferior rectal veins below pectinate line; GSA fibers = painful

May result from pregnancy or constipation
May be a sing of portal hypertension
Internal anal sphincter kept tonically contracted by
sympathetic nerves
External anal sphincter kept tonically contracted by
inferior rectal (somatic) nerves
Internal anal sphincter is relaxed by
parasympathetic fibers
Puborectalis m. relaxes by
somatic control from direct branches of S4 and pudendal nerves (S2-S4)
Perineum is mainly innervated by
pudendal (somatic) nerve
Pudendal nerve leaves the pelvis through the
greater sciatic foramen
Pudendal nerve enters perineum through
lesser sciatic foramen
The pudendal n. is accompanied by what vessels in the perineum (2)?
Internal pudendal artery / vein
Terminal branches of pudendal nerve
inferior rectal nerve
perineal nerve
dorsal nerve of penis / clitoris
Inferior rectal nerves supply
motor: external anal sphincter
sensory: skin of anal triangle
Perineal nerve supplies
motor: urogenital triangle
sensory: skin on posterior surface of scrotum / labia majora
Urogenital triangle muscles innervated by
perineal nerve
Skin on posterior surface of scrotum / labia majora innervated by
perineal nerve
Skin of anal triangle innervated by
inferior rectal nerves
Pudendal nerve block provides anesthesia over
S2-S4 dermatomes and lower 1/4 of vagina
Anesthesize skin of perineum to relieve pain of childbirth
Transvaginal pudendal nerve block
Needle inserted through posterolateral vaginal wall and through sacrospinous ligament near ischial spine
Perineal pudendal nerve block
Needle inserted percutaneously through the buttock and medial to ischial tuberosity
Perineum lymph mainly drains to
superficial inguinal nodes
deep inguinal nodes
Testicular lymph drains to
lateral aortic / para-aortic or lumbar nodes
Pelvic sympathetic action
contraction of internal urethral sphincter → inhibits urination
contraction of internal anal sphincter → inhibits defecation
contraction of ductus deferens, seminal vesicle, prostate → ejaculation
Pelvic parasympathetic action
contraction of detrusor muscle → urination
inhibits internal urethral sphincter → defecation
inhibits contraction of internal anal sphincter → defecation
vasodilation of erectile bodies → erection
Female external genitalia
Labia majora
Labia minora
Mons pubis
Posterior commissure
Vestibule
Frenulum
Prepuce of clitoris
Fourchette