Part III: Pelvis Pg 87-96 Flashcards
What forms the obturator foramen?
Ischial ramus forms inferior margin
Inferior pubic ramus forms anteromedial portion
concavity between ischial spine and ischial tuberosity
Lesser sciatic notch
concavity superior to ischial spine (adjacent to ilium)
Greater sciatic notch
large posteroinferior protuberance on ischial ramus
Ischial tuberosity
What forms the acetabulum?
- body of the ilium
- body of the ischium
- superior ramus of the pubis
What kind of joint is the pubic symphysis? What other joints are similar?
Fibrocartilaginous
- IVDs, xiphisternal, manubriosternal, sacrococcygeal
What forms the pubic arch?
inferior pubic rami and ischial rami from both sides
What about the pelvic girdle differs by gender?
Subpubic angle
Describe the pelvis is in anatomical position?
- ASIS and pubic symphysis are in same vertical plane
- Pelvic canal curves obliquely posterior relative to abdominal cavity
superior pelvic aperature open to abdominal cavity
Pelvic inlet
inferior pelvic aperature closed by muscular pelvic diaphragm
Pelvic outlet
The pelvic inlet is bounded by the pelvic brim which consists of:
- Sacral promontory and ala
- Ilial arcuate line
- Superior pubic ramus and pubic symphysis
The pelvic outlet is bounded by:
- Pubic arch
- Ischial tuberosities
- Sacrotuberous L
- Tip of coccyx
The Inferior (pelvic) portion of abdominal cavity, located superior to pelvic inlet and Bounded by anterior abdominal wall, iliac alae and L5 vertebra.
Greater Pelvis
- Also known as false pelvis and pelvis major
What pelvic viscera are found in the greater pelvis?
Ilium and sigmoid colon
The space between the pelvic inlet and pelvic outlet that is closed inferiorly by musculofascial pelvic diaphragm
Lesser Pelvis
- Also known as true pelvis and pelvis minor
What viscera are contained in the lesser pelvis?
urinary bladder, uterus, ovaries, rectum
Weight bearing compound joint between sacrum and ilium
Sacroiliac Joint
What kind of joint is found posteriorly between tuberosities of sacrum and iliac at SI joint?
Syndesmosis
What kind of joint is found anteriorly between auricular surfaces of sacrum and iliac at SI joint?
Synovial joint
thin anterior part of capsule around synovial joint (anterior) SI joint
Anterior Sacroiliac L
broad fibrous connections between tuberosities of SI joint
Interosseus Sacroiliac L
What Ligament is Primarily responsible for weight transfer at the SI joint
Interosseus Sacroiliac L
Ligament with thick, obliquely oriented fibers (superolaterally) that will draw the ilia inward (medially) with weight bearing?
Posterior Sacroiliac L
Helps to firmly lock together the irregular surfaces of sacroiliac joint
What ligament spans from lateral sacrum to ischial tuberosity?
Sacrotuberous L
What ligament spans from lateral sacrum to ischial spine?
Sacrospinous L
What is the combined function of the Sacrospinous L and Sacrotuberous L?
limit upward movement of inferior part of sacrum and resist sacral rotational movement during periods of sudden weight gain, i.e. landing a jump from a high vertical distance
What ligaments contribute to formation of Greater and Lesser Sciatic Foramen?
Sacrotuberous L and Sacrospinous L
What are the components of the lumbosacral joint?
Anteriorly, IVD between L5-S1
Posteriorly, zygapophyseal joints between articular processes
What ligaments span from L5 transverse processes to medial surface of ilial ala
Iliolumbar L
What ligaments strengthen the sacrococcygeal joint?
Anterior/posterior Sacrococcygeal L
Which gender typically has a thicker fibrocartilaginous disc in the pubic symphysis?
Females
Thickening of the pubic symphysis that spans pubic symphysis laterally to pubic tubercles
Superior pubic ligament
Thickening of the pubic symphysis that rounds the subpubic angle, forming the pubic arch
Inferior pubic ligament
The anterior pelvic wall is formed by:
bodies and rami of pubic bones and pubic symphysis
The lateral pelvic walls are formed by:
hip bones with Obturator Foramen
Obturator foramen is largely closed by:
Obturator Membrane
What attaches to internal surface of obturator membrane and ilium/ischium
Obturator internus muscle
From its attachment on the internal surface of the obturator membrane, what is the path of the obturator internus muscle?
Passes posteriorly from lesser pelvis through Lesser Sciatic Foramen and then turns sharply laterally to attach to Greater Trochanter of Femur
What innervates obturator internus muscle?
Nerve to obturator internus (L5-S2)
What is the action of obturator internus muscle?
laterally rotates thigh, holds head of femur in acetabulum
The tendinous Arch of Obturator Fascia is an attachment point for:
Levator Ani M
The posterior pelvic wall is formed by:
sacrum/coccyx, sacroiliac joints and associated ligaments
NOTE: Actually more like a roof in anatomical position
Where does the piriformis muscle attach?
- Attaches to 2nd-4th sacral segments and Sacrotuberous L
- Attaches to Greater Trochanter of Femur
From its attachment on the 2nd-4th sacral segments and Sacrotuberous L, what is the path of the piriformis muscle?
Exits lesser pelvis laterally through Greater Sciatic Foramen and attaches to Greater Trochanter of Femur
What nerves cross internal surface of the piriformis?
Nerves of Sacral Plexus
What innervates the piriformis muscle?
S1-S2 ventral rami
What is the action of the piriformis muscle?
laterally rotates and abducts thigh, holds femur head in acetabulum
The pelvic floor is formed by:
Pelvic Diaphragm which is a Funnel shape spanning between lateral walls, pubis and coccyx
The pelvic diaphragm consists of which muscles and their fascial coverings?
Levator Ani M and Coccygeus M
What separates the pelvic cavity (lesser cavity) from the perineum?
Pelvic diaphragm
What forms a muscular sling for supporting abdominopelvic viscera and resists increases in intra-abdominal pressure?
Levator Ani M
What innervates levator ani muscle?
S4 ventral rami and Inferior Rectal N (from Pudendal N)
What is the action of the levator ani muscle?
raise pelvic floor and compress abdominopelvic contents
- Important during forced expiration, coughing, sneezing, vomiting, urinating, defecating and lifting heavy objects
- Also plays a role in voluntary control of urination and defecation
Narrow medial part of Levator Ani M that forms U-shaped sling from R/L Pubic bodies to anorectal junction.
Puborectalis M
What muscle surrounds the urogenital hiatus and and creates the puborectal sling?
Puborectalis M (a part of levator Ani M)
What is the puborectal sling?
It forms the anorectal flexure at the anorectal junction which is important in maintaining fecal continence
Levator ani M is divided into three parts:
- puborectalis M
- pubococcygeus M
- Iliococcygeus M
What is the main intermediate par of Levator Ani M?
Pubococcygeus M
What muscle spans from pubis to coccyx?
Pubococcygeus M (the pain part of Levator ani M)
What muscle attaches, in part, to anterior part of tendinous arch of obturator fascia?
Pubococcygeus M
Posterolateral part of Levator Ani M; often thin and aponeurotic
Iliococcygeus M
What muscle spans from posterior part of tendinous arch to coccyx?
Iliococcygeus M (part of levator Ani M)
What muscle spans from ischial spine to inferior sacrum and coccyx and lies on pelvic surface of Sacrospinous L?
Coccygeus M
What innervates coccygeus M?
S4-S5 ventral rami
What is the action of Coccygeus M?
Contributes to Levator Ani M in forming the pelvic diaphragm
Pelvic fascia consists of CT in space between ______ and _______.
parietal peritoneum and muscular pelvic walls
Pelvic fascia is continuous with _________ in the abdomen.
Endoabdominal fascia
Describe the parietal Pelvic Fascia
Membranous CT lining pelvic surface of muscles on pelvic floor and walls
Describe the visceral pelvic fascia
Adventitial layer of CT ensheathing and allowing for distinction of pelvic organs including Urinary Bladder, Prostate, Vagina, Uterus and Rectum
Visceral pelvic fascia is continuous with ______ at point pelvic organ penetrates pelvic floor
parietal fascia
The continuous bilateral fibrous sling of fascia that spans from pubis to sacrum along pelvic floor
Tendinous arch of pelvic fascia
The tendinous arch of pelvic fascia in males, forms the ______ spanning anteriorly from prostate to pubis _____ spanning posteriorly from sacrum to prostate.
- puboprostatic L
- sacrogenital L
The tendinous arch of pelvic fascia in females, forms the _______ spanning anteriorly from urinary bladder to pubis _______ spanning posteriorly from sacrum to vagina
- pubovesical L
- Uterosacral L
Internal iliac is a branch of:
Common iliac which branches from abdominal aorta
What are the two division of the internal iliac artery?
Anterior and posterior
The anterior branch of the internal iliac artery can have many branches (6 in males and 7 in females). What are those?
- umbilical A
- Obturator A
- inferior vesicle A (only in males)
- Uterine A (only in females)
- Vaginal A (only in females)
- MIddle rectal A
- Internal Pudendal A
- inferior gluteal A
Where is the umbilical A located?
between urinary bladder and lateral wall of pelvis. It becomes mostly obliterated.
What branches from the Umbilical A to supply the surface of the bladder?
Superior vesicle A
Prenatally, what does the umbilical artery do?
carries blood from fetus to placenta for reoxygenation
Postnatally, what does the umbilical artery do?
atrophies and becomes fibrous distal to Superior Vesical A. The fibrous umbilical artery is then known as the medial umbilical L in the medial umbilical fold
Where is the obturator artery located?
Passes along lateral wall of pelvis to Obturator Canal, where it exits the pelvis with obturator V and N
What does the obturator artery supply?
Muscles of the medial thigh
Also provides small branches to the ilium and pubis
Although the obturator artery usually branches from the anterior division of internal iliac artery, 25-30% of the time, it originates from ______ or ______.
External Iliac A or Inferior Epigastric A
In males, what supplies blood to inferior surface of urinary bladder, seminal vesicles and prostate and may also provide a branch to ductus deferens?
Inferior vesicle A
In females, what artery supplies numerous branches to anterior/posterior surfaces of vagina, inferior surface of urinary bladder and pelvic urethra?
Vaginal artery
There are two branches of the anterior division of internal iliac artery, one in males and one in female, that homologous. What are these two arteries?
Inferior vesicular A in males and vaginal A in females
What artery branching from the anterior division of internal iliac artery in females on, supplies uterus, cervix and superior parts of vagina?
Uterine artery
The uterine artery is the female homologous to what male structure?
Ductus deferens
What branch of the anterior division of internal iliac artery supplies the inferior part of the rectum?
Middle rectal artery
The middles rectal artery anastomoses with two other arteries to supply the rectum. What are they and where do they branch from?
- Superior rectal A from inferior mesenteric A
- Inferior rectal A from internal pudendal A
What is the path of internal pudendal A as it exits the pelvis?
It passes through the inferior part of Greater Sciatic Foramen, over the sacrospinous ligament, through the lesser sciatic foramen in the pudendal canal with the pudendal N
What is the Primary arterial supply to perineum and external genitalia?
Internal Pudendal A
NOTE: often larger in males
Inferior gluteal A is a branch of anterior division of internal iliac A. What does it supply?
Supplies lower gluteal muscles and upper posterior thigh muscles
As the inferior gluteal artery branches from anterior division of Internal Iliac A, where is it located?
The branch passes posteriorly between S2 and S3 ventral rami
Inferior gluteal A exits the pelvis by passing through where?
inferior part of Greater Sciatic Foramen, inferior to piriformis M
The posterior division of Internal iliac A typically has three branches. What are they?
- iliolumbar A
- lateral sacral A
- superior gluteal A
What is the course of the iliolumbar artery?
Superolateral to iliac fossa where is divides
Iliolumbar Artery divides into:
Iliac branch
Lumbar branch
The iliac branch of iliolumbar artery supplies what?
Iliacus M
The lumbar branch of iliolumbar A supplies what?
Psoas major M and quadratus lumborum M
What does the lateral sacral A supply?
- Spinal meninges around roots of sacral nerves
- skin and deep muscles overlying posterior aspect of sacrum
Superior gluteal artery passes between ______ and _____.
Lumbosacral Trunk and S1 ventral ramus
Superior gluteal A exits the pelvis by passing through what?
superior part of Greater Sciatic Foramen and superior to piriformis M
What does the superior gluteal artery supply?
upper gluteal muscles and Tensor Fascia Lata M
Ovarian/testicular artery is a branch of?
Abdominal aorta, inferior to the renal A
What does the ovarian A supply?
Ovaries and uterine tube
In the pelvis, the ovarian A passes medically through _________.
suspensory ligament of ovary
How does the testicular artery exit the pelvis?
Enters deep inguinal ring and then passes through inguinal canal to scrotum
What does the testicular artery supply?
Testis and epididymus
Where does the median sacral artery arise from?
Posterior surface of abdominal aorta just superior to the bifurcation
The medial sacral artery represents what embryological structure?
Caudal end of embryonic dorsal aorta
Superior rectal artery is a terminal branch of what?
Inferior mesenteric artery
What does superior rectal artery supply
Superior part of rectum
Anastomoses with middle and inferior rectal artery
What is the primary venous drainage of the pelvis?
Internal iliac vein which drains to common iliac V and then IVC
The right and left common iliac veins join to form IVC at what vertebral level
L5
The Pelvic Venous Plexuses is a venous network around rectum, urinary bladder, prostate, uterus and vagina that usually drains to _______.
Internal iliac vein
The Pelvic Venous Plexuses is a venous network around rectum, urinary bladder, prostate, uterus and vagina that sometimes drains to _______ and _______.
Superior rectal V -> IMV
Lateral sacral V -> internal vertebral plexus
What nerves do the lumbar plexus give rise to?
Obturator N
Lumbosacral TRunk
What spinal segmental VPR give rise to Obturator N?
L2-L4
Obturator nerve enters the pelvis on the medial border of what muscle?
Psoas major M
What is the obturator canal?
An opening in the obturator membrane that otherwise fills the obturator foramen
What does the obturator N supply?
Adductors of the medial thigh after it splits into anterior/posterior division
What spinal segmental VPR give rise to lumbosacral trunk?
L4-L5
The lumbosacral trunk passes anterior to _______ to join sacral plexus?
Ala of sacrum
The sacral plexus Nerves lie on the ventral surface of _______.
Piriformis M
What spinal segment VPR comprise the sacral plexus?
L4-S4
How do most branches of sacral plexus exit the pelvis?
Via grater sciatic foramen
What is the largest, broadest nerve in the body?
Sciatic N, a branch of the sacral plexus of nerves
The ventral rami that form the sciatic nerve converge on the anterior surface of _______.
Piriformis muscle
How does the sciatic nerve exit the pelvis?
Inferior to piriformis M via the greater sciatic foramen
What does the sciatic nerve innervate?
Posterior thigh and entire leg and foot via its branches
What is the main motor and sensory nerve of the perineum?
Pudendal N
Where does the pudendal N terminate?
In genitalia as dorsal N of penis/clitoris
What Spinal nerve VPR form the pudendal N?
Anterior divisions of S2-S4
How does the pudendal N exit the pelvis?
With pudendal artery and vein via greater sciatic foramen, posterior to ischial spin and over sacrospinous L
How does the pudendal N enter the perineum?
By passing through the lesser sciatic foramen
Superior gluteal nerve arises from what VPR?
Posterior division of L4-S1
How does superior gluteal nerve exit the pelvis?
Superior to piriformis M via greater sciatic foramen, paralleling superior gluteal AV
What does the superior gluteal N innervate?
Gluteus Medius M, Gluteus Minimus M and Tensor Fascia Lata M
Inferior gluteal N arises from what VPR?
posterior divisions of L5-S2
How does the inferior gluteal N exit the pelvis?
Inferior to piriformis M via the greater sciatic foramen, paralleling inferior gluteal AV
What does the inferior gluteal N innervate?
Gluteus Maximus M
What is the small network of nerves arising from S4-S5 ventral rami?
Coccygeal plexus of nerves
Coccygeal plexus of nerves lies on pelvis surface of ________.
Coccygeus M.
What does coccygeal plexus of nerves innervate?
Coccygeus M and Levator Ani M and skin between coccyx and anus
The Inferior continuation of lumbar sympathetic trunks - Usually comprised of four ganglia (smaller in size than lumbar ganglia)
Sacral sympathetic trunks
What is the Small, median convergence of sacral sympathetic trunks, located anterior to coccyx?
Ganglion impair
What is the function of sacral sympathetic trunk?
Provide postsynaptic sympathetic innervation in lower limbs for vasomotor, sudomotor and pilomotor
The pelvic splanchnic N contains what kind of neurons?
presynaptic neurons arising from S2-S4 spinal cord segments
What does the pelvic splanchnic N innervate?
- muscles of urinary bladder and rectum
- erectile tissue of the penis and clitoris
The pelvic splanchnic N contains visceral afferents from pelvic organs that may refer pain to what dermatomes?
S2-S4
Where is the superior hypogastric plexus?
Inferior to the biforcation of the abdominal aorta
The superior hypogastric plexus contains sympathetics from ______.
Lumbar splanchnic N
Sympathetics from lumbar splanchnic N that lie in the superior hypogastric plexus function is?
Vasomotor
There is minimal parasympathetic contribution to the superior hypogastric plexus via ______.
Pelvic splanchnic N.
What Connects Superior Hypogastric Plexus with Inferior Hypogastric Plexus?
Right and Left hypogastric N
NOTE: Sympathetics pass inferiorly to join with Inferior Hypogastric Plexus and Parasympathetics pass superiorly to join with Superior Hypogastric Plexus
Inferior hypogastric plexus follows branches of _____ to pelvic viscera?
Internal iliac A.
where is the inferior hypogastric plexus?
Between Internal iliac AV, lateral to rectum, vagina and urinary bladder
In males, what does the inferior hypogastric plexus innervate?
prostate, seminal vesicles, penile erectile tissue
In females, what does the inferior hypogastric plexus innervate?
ovary, uterine tube, uterus, vagina, clitoral erectile tissue
In both sexes, what does the inferior hypogastric plexus innervate?
Rectum and urinary bladder