Anatomy Flashcards
Name the avascular spaces in the pelvis
Paired
- Paravesical
- Pararectal
Unpaired
- Retropubic space of Retzius
- Vesicovaginal space
- Rectovaginal space
- Presacral space
What’s the most narrow portion of the colon and it’s at what spinal level?
- Rectosigmoid junction
- Located at S3
Anal Questions
- How long is the anal canal?
- The pectinate line divides the anal into?
Anal Questions
- How long is the anal canal?
- 4 cm
- The pectinate line divides the anal into?
- The upper two-thirds and lower third of the anal canal.
- Developmentally, this line represents the hindgut-proctodeum junction
What’s the significance of the pectinate line?
Differences between internal and external sphincter?
Internal sphincter
- Involuntary
- Smooth muscle
External sphincter
- Voluntary
- Skeletal muscle
Name the uterine support structures
- Broad ligament
- Round ligament
- Utero-ovarian ligament (ovarian ligament)
- Infundibulopelvic (IP) ligament (suspensory ligament of the ovary)
- Uterosacral ligament
- Cardinal ligament
Ureter lies in what relation to the IP ligament?
Medial and posterior to the IP ligament
The utero-ovarian ligament is a remnant of _______
gubernaculum
The round ligament is
- Homologous to _________
- Embryologically related to _________
- gubernaculum testis
- utero-ovarian ligament
- What’s the course of the round ligament?
- Discuss the clinical significance of the round ligament
- What’s the course of the round ligament?
- Lateral anterior uterine corpus ⇒ retroperitoneal space ⇒deep inguinal ring⇒inguinal canal⇒superficial inguinal ring⇒ subcutaneous tissue of labia majora.
- Discuss the clinical significance of the round ligament
- Lateral to the inferior epigastric vessels on AAW
- Labial abscess can be due to connection into the peritoneal cavity given the course of the round
- Contains Sampson’s artery
- Window into the retroperitoneum especially if you get lost.
What makes up the parametrium?
Parametrium = Cardinal ligament + uterosacral ligament
Discuss the significance of the uterosacral ligament
- Attaches cervix to the sacrum (S2-S4)
- Forms boundaries of pouch of douglas
- Forms lateral boundaries of presacral space (along with the ureter)
- Part of level I pelvic support to cervix and upper vagina
- Contains pelvic autonomic nerves, blood supply, and lymphatics
- With the cardinal ligament, forms the parametrium.
Significance of the cardinal ligament?
- Thickening of visceral layer of pelvic fascia around uterine artery
- Attaches cervix & upper vagina ⇒ pelvic sidewall
- Contains uterine vessels
- Forms part of Level I pelvic support
- Forms boundaries of pararectal and paravesical space
Branches of the internal iliac artery?
Mnemonic:
I Love Going Places In My Very Own Underwear!
I: iliolumbar artery
L: lateral sacral artery
G: gluteal (superior and inferior) arteries
P: (internal) pudendal artery
I: inferior vesical (vaginal in F) artery
M: middle rectal artery
V: vaginal artery
O: obturator
U: umbilical artery and uterine artery
Describe the course of the internal pudendal artery
- Branch of Anterior Division of internal iliac artery that supplies the perineum
- Exits pelvis through greater sciatic foramen BELOW piriformis
- Re-enters pelvis through lesser sciatic foramen
- Through Alcock’s canal
Branches of the internal pudendal artery?
- Inferior rectal artery
- Perineal artery
- Posterior labial arteries
- Artery of bulb of vesitibule
- Dorsal artery of clitoris
- Deep artery of clitoris
External pudendal artery is a branch of _______
Two types of the external pudendal artery include?
External pudendal artery is a branch of _______
- Branch of femoral artery
- supplies the perineum
Two types of external pudendal artery include?
- Superficial External pudendal artery – pierces femoral sheath, across round ligament and superficial to inguinal ligament
- Deep external pudendal artery – passes medially across Pectineus/adductor longus m and anastomose with labial branches
- Both supply labia majora
Blood supply to the ureter?
- Lots of collateral circulation!
- Very resilient if transected
Boundaries of the Retropubic Space of Retzius?
Anteriorly: Symphysis pubis
Laterally: Pubic rami and obturator internus muscles
Posteriorly: Urinary bladder
Floor: Anterior vagina (in women) and proximal urethra
What is the clinical significance of the Retropubic space of Retzius?
What do you have to be cautious about when entering this space?
- Important for doing exenterations or urogyn procedures such as Burch or slings
- Veins of Santorini, dorsal artery and vein of clitoris, obturator bundle
- What are the borders of the vesicovaginal space?
- What is clinically significant about this space?
- What are the borders of the vesicovaginal space?
- Anterior – Bladder adventitia
- Posterior – Vagina/Endopelvic fascia
- Lateral – Vesicouterine “webs” or vesicouterineligaments or “bladder pillars” (not seen in this picture)
- What is clinically significant about this space?
- Allows access to bladder, cervix, vagina, distal ureters
- Hysterectomy
- Sacrocolpopexy
- Vesicovaginal fistula repair
- Allows access to bladder, cervix, vagina, distal ureters
- What are the borders of the rectovaginal space?
- What is the clinical significance of this space?
- What are the borders of the rectovaginal space?
- Anterior- Vagina
- Posterior- Rectum
- Lateral- Uterosacral ligaments
- What is the clinical significance of this space
- Sacrocolpopexy
- Rectovaginal fistula repair
- Low anterior resection
- Radical hysterectomy
What is the lowest point in the pelvis?
Pouch of Douglas
- aka Rectouterine pouch or Rectovaginal pouch
- extension of peritoneum between uterus and rectum
- What are the borders of the presacral space?
- What is the clinical significance of the presacral space?
- What are the borders of the presacral space?
- Anterior: Rectum
- Posterior: Sacrum
- Superior: Peritoneal reflection of rectum
- Inferior: Waldeyer’s fascia (3-5 cm proximal to anorectal junction), levator ani
- Lateral: Uterosacral ligaments, ureter
- What is the clinical significance of the presacral space?
- Middle sacral vessel
- Hypogastric plexus
- What is the clinical significance of presacral fascia?
- What is Waldeyer’s fascia?
- What is the clinical significance of presacral fascia?
- Presacral fascia lines the anterior aspect of the sacrum, enclosing the sacral vessels and nerves. It continues anteriorly as the pelvic parietal fascia, covering the entire pelvic cavity.
- The presacral fascia is limited postero-inferiorly, as it fuses with the mesorectal fascia, lying above the levator ani muscle, at the level of the anorectal junction. These two fascias have been erroneously confused, though they are in fact, separate anatomical entities. The colloquial term, among colo-rectal surgeons, for this inter-fascial plane, is known as the holy plane of dissection first coined by Bill Heald.
- During rectal surgery and mesorectum excision, dissection along the avascular alveolar plane between these two fascias, facilitates a straightforward dissection and preserves the sacral vessels and hypogastric nerves.
- What is Waldeyer’s fascia?
- Waldeyer’s fascia (a.k.a. rectosacral fascia) originates from the presacral parietal fascia at the S2 to S4 level fusing with the rectal visceral fascia at the posterior aspect of the rectum.
- Waldeyer’s fascia divides the retrorectal space into a superior and inferior compartments.
- What are the boundaries of the paravesical space?
- What is the clinical significance of this space?
- What are the boundaries of the paravesical space?
- Anterior: Pubic symphysis
- Posterior: Cardinal Ligament Web
- Lateral: External Iliac Vein, obturator internus muscle
- Medial: Superior vesical artery
- Inferiorly: pelvic floor
- What is the clinical significance of this space?
- Pelvic LND
- Radical hysterectomy
- Allows entry into the retropubic space of retzius
- What are the boundaries of the pararectal space?
- Clinical significance of this space?
- What are the boundaries of the pararectal space?
- Anterior: Cardinal Ligament Web
- Posterior: Sacrum
- Lateral: Internal Iliac Artery
- Medial: Ureter, rectum
- ureter can be medial or lateral depending on how you mobilize: GYN mobilizes it medially and colorectal mobolizes it laterally.
- Clinical significance of this space?
- Space is entered for pelvic LND, Radical hysterectomy, or LAR
- Allows us entry into the presacral space
Give a broad overview of the body’s nervous system
- What are the two pelvic nerve plexuses?
What are the branches of the lumbar plexus?
- Iliohypogastric (L1)
- Also receives innervation from T12
- Ilioinguinal (L1)
- Also receives innervation from T12
- Genitofemoral (L1-2)
- Lateral Femoral Cutaneous (L2-3)
- Femoral (L2-4)
- Obturator (L2-4)
Pathway of the lumbar nerve plexus branches?
- Iliohypogastric (L1)
- Comes out most superior and lateral
- Ilioinguinal (L1)
- Wraps around iliac crest and travels through inguinal ligament
- Genitofemoral (L1-2)
- Comes through psoas muscle
- Lateral Femoral Cutaneous (L2-3)
- Comes out lateral to psoas muscle
- Femoral (L2-4)
- Comes out lateral to psoas muscle
- Obturator (L2-4)
- What is the function of the genitofemoral nerve?
- How is the genitofemoral nerve injured?
- What is the function of the genitofemoral nerve?
- Femoral branch: sensory to upper anterior thigh
- Genital branch: sensory to mons pubis and labia majora
- How is the genitofemoral nerve injured?
- Retractor placement or transection
- What is the function of the lateral femoral cutaneous nerve?
- How is it injured?
- What is the function of the lateral femoral cutaneous nerve?
- Sensory to skin of anterior, lateral thigh
- How is it injured?
- Compression from hyperflexion of hip
- What is the function of the femoral nerve?
- How is it injured?
- What is the function of the femoral nerve?
- Motor to muscles that extend the knee (absent knee jerk if injured)
Sensory to upper thigh and inner leg
- Motor to muscles that extend the knee (absent knee jerk if injured)
- How is it injured?
- Position, retractor placement, childbirth and inguinal node dissection
- What is the function of the obturator nerve?
- How is the obturator nerve injured?
- What is the function of the obturator nerve?
- Motor to adductor muscles of thigh
- Sensory to medial, distal thigh
- How is the obturator nerve injured?
- Transection or injury during pelvic node dissection or sling placement
Describe the sensory distribution of the lumbar nerve plexus branches
Describe the motor distribution of the lumbar nerve plexus branches
- Are sacral nerve plexus branches somatic or autonomic?
- Where does the sacral nerve plexus lie?
- What does it comprise of?
- What are the branches of the sacral nerve plexus branches?
- Are sacral nerve plexus branches somatic or autonomic?
- somatic
- Where does the sacral nerve plexus lie?
- lies on the piriformis muscle
- What does it comprise of?
- Lumbosacral trunk (L4-5)
- Anterior rami of S1-4
- What are the branches of the sacral nerve plexus branches?
- Superior gluteal
- Inferior gluteal
- Posterior femoral cutaneous
- Sciatic
- Pudendal
- What are the nerve roots of the sciatic nerve?
- What is the function of the sciatic nerve?
- Discuss its course
- What are its terminal branches?
- What are the nerve roots of the sciatic nerve?
- L4-S3
- What is the function of the sciatic nerve?
- Motor and sensory to lower extremity
- Discuss its course
- Exits pelvis through greater sciatic foramen inferior to the piriformis
- Runs along posterior thigh to popliteal fossa
- What are its terminal branches?
- Tibial nerve – travels to posterior compartment of leg into the foot
- Common fibular nerve – travels to anterior and lateral compartments of leg into the foot
- What are the nerve roots of the pudendal nerve?
- Whare the branches of the pudendal nerve?
- Function of the pudendal nerve?
- What’s the course of the pudendal nerve?
- What are the nerve roots of the pudendal nerve?
- S2-S4
- Whare the branches of the pudendal nerve?
- inferior rectal nerves
- Terminal branches: see figure
- Function of the pudendal nerve?
- Supplies motor and sensory to all perineal structures
- What’s the course of the pudendal nerve?
- Exits the greater sciatic foramen and enters Alcock’s canal to the perineum
What is Alcock’s canal?
- aka pudendal canal
- Formed by obturator internus fascia
- Contains internal pudendal artery & veins, pudendal nerve
What are the terminal branches of the pudendal nerve?
See figure
Describe the somatic and autonomic nerve divisions in the pelvis?
What are the differences between sympathetic and parasympathetic fibers?
- Preganglionic fibers
- Sympathetic = short
- Parasympathetic = long
- Postganglionic fibers
- Sympathetic = long
- parasympathetic = short
- Neurotransmitter release
- Sympathetic: NE on alpha + Beta receptors
- Parasympathetic: ACh on muscarinic receptors
Summary slide of nerve plexuses
- Superior hypogastric nerve plexus -> Right & Left hypogastric nerve
- Hypogastric nerve + sacral splanchnic + pelvic splanchnic join to become the inferior hypogastric nerve plexus