SM_220-221b: Anatomy of the Pelvis and Perineum I and II Flashcards
___ is the diamond-shaped pelvic outlet
Perineum is the diamond-shaped pelvic outlet
Perineum is subdivided into the ____ and ____
Perineum is subdivided into the anterior urogenital triangle and posterior anal triangle
Perineum has superior boundary of ____ and lateral boundary of ____
Perineum has superior boundary of pelvic diaphragm and lateral boundary of obturator internus muscle
Urogenital diaphragm is ____ closing off the urogenital triangle
Urogenital diaphragm is two fascial layers closing off the urogenital triangle
- Superior fascia of urogenital diaphragm
- Inferior fascia (perineal membrane)
____ is deep to urogenital diaphragm
Pelvic diaphragm is deep to urogenital diaphragm
Describe perineum landmarks in midsagittal segment
Perineum landmarks in midsagittal segment
- Male: UG diaphragm is always in line with pubic symphysis and perineal body in front of the rectum
- Female: UG diaphragm and perineal body are in line with pubc symphysis
Pubovesicular ligmanent in the female is analogous to ___ in the male
Pubovesicular ligmanent in the female is analogous to puboprostatic ligament in the male
Muscles in the UG diaphragm are ____ and ____
Muscles in the UG diaphragm are external urethral sphincter and deep transverse perineal muscle
- Bulbourethral gland in male is also within UG diaphragm
- Greater vestibular gland in female is superficial to UG diaphragm
Deep pouch is ____, while the superficial pouch is ____
Deep pouch is interior of the UG diaphragm, while the superficial pouch is the scrotum or labia majora (superficial body wall)
Superficial pouch of Colle’s fascia is tightly attached to the ____ and ____
Superficial pouch of Colle’s fascia is tightly attached to the back edge of the UG diaphragm and perineal body and fascia lata of the thigh
- Blood or urine in the superficial pouch can only pass upward into the body wall between the superficial and deep layers
Superficial pouch contains ____
Superficial pouch contains everything superficial to the UG diaphragm
Diaphragms from deep to superficial are ____ and ____
Diaphragms from deep to superficial are pelvic diaphragm and UG diaphragm
- Pelvic diaphragm: levator ani (pubococccygeus, iliococcygeus), ischiococcygeus
- UG diaphragm: superficial fascia and inferior fascia (perineal membrane)
Describe contents of the superficial pouch of the UG diaphragm
Contents of the superficial pouch of the UG diaphragm
- Bulb and crura of penis, clitoris, vestibular bulb, and greater vestibular gland
- Bulbospongiosus, ischiocavernosus, and superficial transverse perineal muscles in both sexes
___ is enlarging the birth canal for an anticipated difficult birth
Episiotomy is enlarging the birth canal for an anticipated difficult birth
Midline episiotomy involves cutting ____
Midline episiotomy involves cutting the central tendon of the perineum (and wall of vagina)
Mediolateral episiotomy involves cutting the ____
Mediolateral episiotomy involves cutting the UG diaphragm, bulbospongiosus, and superficial transverse perineal muscles
____ is somatic innervation (S2-4) for perineum body wall
Pudendal nerve is somatic innervation (S2-4) for perineum body wall
- Perineum body wall: UG diaphragm, genitalia, external anal sphincter, and skin of perineum
- Branches: inferior rectal branch, perineal, and dorsal nerve of penis
___ enter the superior hypogastric plexus, while ___ leave the S2-4 ventral rami
Lumbar splanchnics enter the superior hypogastric plexus, while pelvic splanchnics leave the S2-4 ventral rami
- Visceral sensory neurons are in all autonomic nerves and plexuses
___ exit with ventral roots T1-L2
Sympathetics exit with ventral roots T1-L2
___ travels from sacral plexus to external anal sphincter and perineum
Pudendal nerve (S-4) travels from sacral plexus to external anal sphincter and perineum
Describe nerve functions
Nerve functions
- Somatic (sacral ventral rami): body wall (skin of perineum, UG and pelvic diaphragms, external anal sphincter, external genital organs)
- Sympathetic (lumbar splanchnics): arteries, internal sphincters, ureters, and ductus deferens
- Parasympathetic (pelvic splanchnics): bladder (micturition), rectum (defecation, peristalsis), and erection of penis / clitoris
Pudendal nerve block anesthetizes ____
Pudendal nerve block anesthetizes UG diaphragm and perineum
Sacral epidural nerve block anesthetizes ____
Sacral epidural nerve block anesthetizes UG diaphragm, perineum, and cervix
____ nerve block is the anesthesia of choice for childbirth
Lumbar epidural nerve block via catheter is the anesthesia of choice for childbirth
- Uterus has lower thoracic and lumbar spinal segments
Sacral epidural block anesthetizes ____
Sacral epidural block anesthetizes cervix and all of vagina
- S2, 3, and 4 via pelvic splanchnic nerves
- Somatic innervation between pudendal nerve
Describe branches of the internal iliac artery
Internal iliac artery branches
Describe exceptions to an internal iliac artery source of blood
Exceptions to an internal iliac artery source of blood
- Upper rectum: inferior mesenteric
- Gonads: aorta, inferior vena cava, left renal vein
- Dorsal veins of penis / clitoris go under the pubic symphysis to the pelvic plexus rather than following the pudendal canal route
Describe the male system
Male system
Describe erectile tissues of the penis
Erectile tissues of the penis
- Left and right crus
- Bulb
- Corpus cavernosum
- Corpus spongiosum
- Glans penis
____ muscle envelops each crus, while the ____ muscle envelops the bulb and proximal corpus spongiosum
Ischiocarvernosus muscle envelops each crus, while the bulbospongiosus muscle envelops the bulb and proximal corpus spongiosum
Each crus continues as the ____, and the bulb continues as the ____
Each crus continues as the corpus cavernosum dorsally, and the bulb continues as the corpus spongiosum ventrally
Describe innvervation of the perineum and external genital organs
Innvervation of the perineum and external genital organs
- Deep artery of penis to corpus cavernosus
- Artery to bulb
- Dorsal nerve / artery / vein to penis clitoris
- Perineal nerve
Describe prostate enlargement
Prostate enlargement
- Outer zone tumors usually cancerous
- Inner zone (median lobe) tumors usually benign and very common
- Effects similar to kidney stones except the bladder is also involved (diverticula and trabeculation of the muscular wall)
Describe prostate surgery and pelvic nerves
Prostate surgery and pelvic nerves
- Removal of the prostate can be done through the urethra, above public bone, or through the perineal body
- If via perineal body, parasympathetics from the pelvic plexus to the penis can be cut, resulting in impotence
Describe female external genitalia
Female external genitalia
- Labia majora: folds of superficial body wall
- Labia minora: flank vestibule (space of the glans with the clitoris and openings of the vagina, urethra, and greater vestibular glands)
____ surrounds the vestibular bulb and greater vestibular gland
Bulbospongiosus muscle surrounds the vestibular bulb and greater vestibular gland
Vagina is primarily ____
Vagina is primarily retroperitoneal
- Has no glands and few sensory nerves
Cervix and fundus are ____, while most of the body is ____
Cervix and fundus are retroperitoneal, while most of the body is peritonealized (in a mesentery)
___ is the angle between vagina and uterus
Anteversion is the angle between vagina and uterus
___ is the angle between the cervix and the body of the uterus
Anteflexion is the angle between the cervix and the body of the uterus
____ is retroversion where the uterus is tipped backward in line with the vagina
Tipped uterus is retroversion where the uterus is tipped backward in line with the vagina
Describe ligaments of uterus
Ligaments of uterus
Describe the broad ligament of the uterus
Broad ligament of the uterus
- Mesosalpyinx: upper part of broad ligament
- Mesovarium: posterior extension of broad ligament
- Mesometrium: broad ligament
Ovarian artery of the aorta reaches ovary through ____
Ovarian artery of the aorta reaches ovary through suspensory ligament of the ovary (lateral part of broad ligament)
- Uterine artery from internal iliac
