220/221. Anatomy of Pelvis/Perineum II/III Flashcards
What are the boundaries of perineum?
What passes through UG triangle?
What passes through anal triangle?
Pubic symphysis (ant) Ischial Tuberosities (lat.) Coccyx (post) Ischiopubic rami (2 ant) Sacrotuberous Ligament (2 post)
UG Triangle: urethra/vagina pass thru
Anal Triangle: rectum/anal canal pass through
What structures make up the UG diaphragm?
What muscles are inside UG diaphragm?
What other structures are in UG diaphragm?
In the male: what is directly above and below UG diaphragm?
UG Diaphragm: Superficial Fascia (deep), Inferior Fascia (perineal membrane; superficial)
Muscles inside: Deep transverse perineal m., ext urethral sphincter (horizontal fibers that pinch urethra)
Males: bulbourethral gland within UG diaphragm
- prostate gland ABOVE UG diaphragm
- bulb of penis BELOW UG diaphragm
Deep Pouch: where is it, what is inside it
Superficial pouch: other names, lining, contents (M and F)
Deep: interior to UG diaphragm, potential space
Superficial: Scrotum (M) or Labia Majora (F)
- lined by Colle’s Fascia (from Scarpa’s Fascia) - deepest part of superficial body wall (adhered to back of UG diaphragm, perineal diaphragm, fascia lata of each thigh so blood can only go upward)
- M: contains crura + bulb of penis surrounded by ischiocavernosus (around each crus) + bulbosponsiosus m. (around bulb), superficial transverse perineal M. lined by perineal membrane, testes
- F: superficial transverse perineal m., clitoris (body and crura), vestibular bulb (like Male corpus spongiosum), greater vestibular gland (like Male bulbourethral gland in UG diaphragm), ischiocavernosus muscle around crura, bulbospongiosus m around vestibular bulb/greater vestibular gland.
Diaphragms: Pelvic vs. UG - which is deeper?
Muscles in each
- Pelvic Diaphragm: deepest
- Levator ani m.: Puborectis, Pubococcygeus, Iliococcygeus
- Ischiococcygeus m. - UG Diaphragm: superficial
- Deep Pouch: Ext Urethral Sphincter m., deep transverse perineal m., bulbourethral gland (only Males)
Episiotomy
- what is it
- what happens to each method
Enlarging of birth canal for anticipated difficult birth
- Mediolateral: cut UG diaphragm, bulbospongiosus m., superficial transverse m., wall of vagina (harder to repair, but less risk of anal sphincter tear)
- Midline: cut central tendon of perineum and wall of vagina (all c.t. = easier to repair, but higher risk of ext anal sphincter tear)
Pudendal N.
- what does it supply
- what structures does it run through?
- name the 3 branches
somatic Nerves: where do they exit spine, what do they innervate
Supplies somatic perineum body wall: UG diaphragm, genitalia, ext anal sphincter, skin of perineum
Runs out greater sciatic foramen (over sacrospinous ligament) and returns back through lesser sciatic foramen to enter pudendal canal
Branches
- Inferior rectal branch: to ext anal sphincter
- Perineal branch: to UG diaphragm scrotum cutaneous
- Dorsal nerve of penis/clitoris: (cutaneous)
Somatic: leave S2-S4 ventral rami (not pudendal) innervate body wall - skin of perineum, UG/PELVIC Diaphragms, ext anal sphincter, ext genital organs
Nerve Blocks
- Sacral Epidural (what is hit)
- Pudendal N Block (what is hit)
- Lumbar Epidural (what is hit)
How are different parts of uterus innervated?
Sacral Epi: S2-S4 and Vis Sensory fibers (hard to find space), hits UG diaphragm, perineum, cervix, vagina
Pudendal N: hits only UG diaphragm, perineum (body wall and lower 1/4 vagina)
Lumbar Epidural: PREFERRED for childbirth, catheter is longer, more controlled
- blocks lower thoracic/lumbar spinal segments to uterus (if subarachnoid may cause CSF leak and Headache)
Uterus Innervation:
T10-L4: Uterus body, fallopian tubes, ovary
S2-4: Cervix, Upper Vagina
Pudendal N: Body wall, lower 1/4 Vagina
Arteries
- Branches of Common Iliac
- Branches of Int. Iliac A. (what is most superior? What courses horizontally? what leaves greater sciatic foramen? what are other branches?)
What are non-iliac sources to pelvis (3)
Common Iliac = Ext Iliac = Femoral A
Int Iliac:
- most superior: Superior Vesicular A. (umbilical a. in fetus, becomes fibrous cord)
- Obturator a. courses horizontally
- leaves greater sciatic foramen: 1. superior gluteal a (above piriformis), 2. inferior gluteal a. (below piriformis), 3. internal pudendal a. (below inf glut)
- other branches: uterine, rectal, inf vesicular (need to ID target organ)
Non-ILIAC
- Upper Rectum: Inferior Mesenteric A.
- Gonads: Aorta = L/R testicular/ovarian A. = L/R gonadal Vein = L Renal Vein/IVC
- Dorsal Veins of Clitoris/Penis follow genital parasymps back under pubic symphysis to pelvic plexus
Male Genitals
- what are the 3 branches of the pudendal nerve and what do they supply
- what is arteries supply genitals?
Pudendal nerve/Int Pudendal A course over sacrospinous ligament
- Dorsal nerve of penis in deep pouch (deepest pudendal n.)
- Perineal N (superficial and deep branches) pierce through pudendal canal)
- Inferior Rectal N. to Ext anal sphincter
Arteries
L/R Artery of Superficial Perineal Pouch = bulbar A. and L/R deep artery of penis = middle of each corpus cavernosus
Female Genitals
- anteversion vs. anteflexion
connections of the following ligaments:
- round ligament of uterus
- suspensory ligament
- ovarian ligament
- broad ligament
- mesosalpinx
- mesovarium
Where do the arteries supplying female genitalia come from?
Anteversion: angle b/w vagina and uterus (most forward)
Anteflexion: angle b/w cervix and uterus body
round ligament: old gubernaculum (uterus to body wall)
Suspensory ligament: ovarian vessels from lateral body wall, where broad ligament hits abd wall (visceral peritoneum becomes parietal)
Ovarian Ligament: old gubernaculum (uterus to ovary)
Broad Ligament: Mesometrium, peritonealizes uterus, ovaries BEHIND this
Mesosalpinx: cover fallopian tube (upper broad ligament)
Mesovarium: cover ovary (post extension of broad ligament)
Uterine A: from Int Iliac (watch out for ureters) - inserts at uterine body/cervix (vagina, uterus, ovary involved)
Ovarian A: from Aorta (through suspensory ligament of ovary = lateral part of broad ligament)
