Lecture 11 (pelvis)

Question 1

List the parts of the pelvis

Answer 1

1) Pelvic girdle
2) Joints and ligaments
3) Paired direct tributaries peritoneum and peritoneal cavity of pelvis
4) Walls and floors of pelvic cavity
5) Pelvic fascia, nerves, vessels, & lymph nodes
6) Pelvic viscera

Question 2

What are the pelvic viscera?

Answer 2

1) Urinary
2) Reproductive organs
3) Urogenital triangle
4) Anal triangle
5) Female and male urogenital triangle

Question 3

What are the two main parts of the pelvic cavity? What marks where each begins?

Answer 3

1) Greater; Supracristal plane
2) Lesser; pelvic brim

Question 4

What are the two main parts of the lesser pelvic cavity? What structures are located at each?

Answer 4

1) Pelvic inlet: Superior pubis to sacral promontory
2) Pelvic outlet: Inferior rami of pubis and Ischial tuberosities anterolaterally; tip of coccyx posterior

Question 5

What are the bones, joints and ligaments of the pelvic girdle?

Answer 5

1) Pubic symphysis
2) Paired Sacroiliac
3) Lumbosacral
4) Sacral coccygeal

Question 6

What are the 3 bones of the bony pelvis?

Answer 6

1) Paired R & L hip (a fusion of 3 bones)
2) Sacrum

Question 7

1) What 3 bones fuse to make up the left and right hips?
2) What makes up the sacrum?

Answer 7

1) Ilium, pubis, and ischium
2) Fusion of 5 sacral vertebrae

Question 8

1) What is the acetabulum
2) What is included in it?

Answer 8

1) “Hip joint” with head of femur
2) Components of all 3 bones of hip

Question 9

1) What do the Sacrospinous and sacrotuberous ligaments prevent?
2) What can they be responsible for?

Answer 9

1) Excessive lumbar lordosis during weight bearing
2) “Back pain”

Question 10

1) What form the anterior inferior wall?
2) What form the lateral wall?

Answer 10

1) Body and rami of pubic bone; pubic symphysis
2) Boney hips, obturator foramen, membrane, muscle, vessels and nerves

Question 11

1) Compare the pubic arches of male and female pelvises
2) Compare the thickness and heaviness of bones of male and female pelvises

Answer 11

1) Males have a narrower pubic arch < 70 degrees; females have a wide pubic arch > 80 degrees
2) Male pelvises have thick and heavy bones; females have thin and light boney structure

Question 12

1) Compare the deepness of male and female greater pelvises
2) Compare the deepness of male and female lesser pelvises

Answer 12

1) Males’ greater pelvis is deep, females’ is shallow
2) Males’ lesser pelvis is narrow and deep; females’ is wide and shallow

Question 13

1) Compare the inlet shapes of male and female pelvises
2) Compare the outlet shapes of male and female pelvises

Answer 13

1) Males’ inlet is heart-shaped; female inlet oval or rounded
2) Males’ outlet is smaller, female outlet larger

Question 14

What is the pelvic floor also called?

Answer 14

Pelvic diaphragm

Question 15

What 3 things cover the pelvic diaphragm?

Answer 15

Levator ani + coccygeus muscles + fascia

Question 16

1) What forms the tendinous arch of levator ani? Where?
2) What are the two primary muscles that make up the levator ani?

Answer 16

1) Obturator fascia (thickened); ~ L5-S4
2) Pubococcygeus and iliococcygeus

Question 17

What make up the pelvic diaphragm?

Answer 17

Levator ani and coccygeus muscles

Question 18

From levator ani to skin of rectum, you can find what?

Answer 18

Perineal compartment

Question 19

What can occur at the ischo-anal fossa of the perineum?

Answer 19

Abscesses

Question 20

What provide the blood and innervation to the perineal compartment? Where does the blood flow come from?

Answer 20

Pudendal vessels (come off anterior internal iliac) and pudendal nerves (lumbo-sacral nerves)

Question 21

List the 4 main muscles of the pelvic walls.
Which makes up the lateral wall? What about the posterior wall?

Answer 21

1) Levator ani
2) Coccygeus m.
3) Obturator internus – lateral wall
4) Piriformis – posterior wall

Question 22

1) Where is the Lumbar-sacral-coccygeal nerve plexus?
2) Where is the sacral nerve plexus?

Answer 22

1) L4-5 lumbosacral trunk to sacral plexus
2) Lumbosacral trunk to sacral plexus + S1-S3 (L4-S3)

Question 23

What two main nerves are formed by the sacral plexus? What does each innervate?

Answer 23

1) Sciatic n.– posterior thigh and leg below knee
2) Pudendal n. – nerve to perineum

Question 24

Besides the two main nerves of the sacral plexus, what else does it form? What does each innervate?

Answer 24

1) Superior gluteal n. – glut min, medius, TFL
2) Inferior gluteal n.– glut max

Question 25

Where is the coccygeal plexus?

Answer 25

S4-5, Co1 to pelvic floor

Question 26

1) Where does the nerve to obturator internus come from?
2) Where does the nerve to piriformis form?
3) Where does the nerve to levator ani and coccygeus m form?

Answer 26

1) L5, S1-2
2) S1-2
3) S3-4

Question 27

1) Where does the sciatic nerve come from and where does it exit?
2) Where does the superior gluteal n come from and exit? What 3 muscles does it innervate?

Answer 27

1) L4 -S3, exits thru greater sciatic foramen, inferior to pyriformis m.
2) L4-S1, exits via greater sciatic foramen, supplies 3 muscles in glut region: gluteus Medius and Minimus mm., & TFL

Question 28

1) Where does the inferior gluteal nerve come from, where does it exit, and where does it go?
2) What come from the coccygeus plexus? What 3 things does it supply?

Answer 28

1) L5-S2, exits via greater sciatic foramen to the Gluteus maximus m.
2) Coccygeal nerves; coccygeus m., parts of levator ani, & sacrococcygeal joint

Question 29

1) Where does the pudendal nerve come from? What is the it main nerves of?
2) Where does it enter?

Answer 29

1) S2-S4, main nerve to the perineum and chief sensory nerve of the external genitalia
2) Enters perineum via lesser sciatic foramen

Question 30

1) Where does the obturator nerve come from?
2) Where does it pass through?
3) What is it the primary nerve to?

Answer 30

1) L2-L4
2) Passes thru the pelvis BUT is not a pelvic nerve
3) Medial (adductor group) thigh

Question 31

1) What do structures do at the greater sciatic foramen?
2) What muscle is located here?
3) What 4 nerves are here?
4) What else is located here?

Answer 31

1) Exit pelvis
2) Piriformis m. to femur
3) Sciatic nerve, pudendal nerve, superior/inferior gluteal n.
4) Vessels

Question 32

1) What do structures do at the lesser sciatic foramen?
2) What muscle is located here?
3) What nerve is here?

Answer 32

1) Exit pelvis and re-enter perineal compartment
2) Obturator internus m.
3) Pudendal nerve

Question 33

What make up pelvic autonomic innervation? (3 categories of things)

Answer 33

1) Sacral sympathetic trunk & pelvic splanchnic nerves
2) Hypogastric plexuses & peri-arterial plexuses
3) Parasympathetics via S2-3-4

Question 34

What are the 3 main parts of pelvic autonomics?

Answer 34

1) Sympathetic
2) Parasympathetic
3) Periarterial plexuses

Question 35

What does sympathetic innervation of the pelvis do? (3 things)

Answer 35

1) Vasomotion
2) Inhibit peristalsis of rectum
3) Stimulates contraction of genital organs during orgasm (ejaculation in males)

Question 36

What does parasympathetic innervation of the pelvis do? (2 things)

Answer 36

1) Stimulate contraction of bladder and rectum
2) Supply erectile bodies of genitalia resulting in erection

Question 37

What does the peri-arterial plexus of the pelvis do?

Answer 37

Provide post synaptic sympathetic vasomotor to: superior rectal, ovarian, & internal iliac

Question 38

1) What is the pelvic pain line?
2) How are afferents of the pelvis conducted?

Answer 38

1) Visceral afferents in the pelvis
2) Centrally

Question 39

1) Reflex visceral afferents (not aware consciously) of the pelvis are conducted how? Where to?
2) How do pain visceral afferents (aware consciously) differ?

Answer 39

1) Via parasympathetic to spinal ganglia S2-3-4
2) Diff. based on “pelvic pain line” that corresponds to the inferior limit of the peritoneum

Question 40

1) What returns to CNS via parasympathetic S2-3-4?
2) What returns to CNS via sympathetic fibers to T-L cord segment ganglia?

Answer 40

1) Viscera inferior & not in contact with peritoneum + distal sigmoid colon and rectum
2) Visceral superior to and in contact with the peritoneum

Question 41

1) How does pain above the pelvic pain line travel back? What does this explain?
2) How does pain below the pelvic pain line return, and what organs are included in this?

Answer 41

1) Via the sympathetic fibers (L1, L2, T4-5, whatever, etc). Explains why some uterine pain hurts higher than you think it should; much of the uterus (less of cervix) is covered by peritoneum.
2) Via S2-3-4 parasympathetics; cervix, vagina, distal rectal anus, male internal genitalia, pt of bladder not touched by peritoneum

Question 42

What are the pelvic viscera?

Answer 42

1) Distal parts of GI (rectum)
2) Distal Urinary tract
3) Reproductive system

Question 43

Why are the parts of the sigmoid colon and small intestines that extend into the pelvic cavity considered abdominal viscera instead of pelvic?

Answer 43

They are mobile from their abdominal mesenteric attachments
(except the very distal sigmoid colon as it transitions into rectum)

Question 44

What structures pass through the pelvic diaphragm to reach the perineal compartment? (3)

Answer 44

1) Rectum
2) Vagina
3) Urethra

Question 45

What are the 3 urinary organs?

Answer 45

1) Ureters
2) Urinary bladder
3) Urethra