Pelvis (its Contents & the Floor)

Question 1

What makes up the “false” (greater) pelvis?

Answer 1

• the part between the iliac crests and the pelvic inlet

Question 2

What makes up the “true” (lesser) pelvis?

Answer 2

• the basin-shaped cavity below the pelvic inlet

Question 3

Which bones make up the pelvis?

Answer 3

• the sacrum and the hip bones on each side

Question 4

Which three bones make up each hip bone?

Answer 4

• pubis, ilium, and ischium

Question 5

What is the large foramen in each hip bone called?

Answer 5

• the obturator foramen

Question 6

What converts the greater and lesser sciatic notches into the greater and lesser sciatic foramina?

Answer 6

• the sacrospinous and sacrotuberous ligaments

Question 7

What is the small opening in the obturator membrane called?

Answer 7

• the obturator canal

Question 8

Is the sub-pubic angle greater in males or in females?

Answer 8

• females

- it is V-shaped in males and U-shaped in females

Question 9

Describe the shape of the obturator foramen in males and females.

Answer 9

• the foramen tends to be circular in males, and more oval in females

Question 10

T or F: the acetabulum is generally larger in females.

Answer 10

• false!

- it is larger in males

Question 11

What makes up the pelvic floor?

Answer 11

• the pelvic diaphragm and the urogenital diaphragm

Question 12

What makes up the pelvic diaphragm?

Answer 12

• the levator ani ani the coccygeus muscles (along with the fascia above and below them)

Question 13

What are the three parts of the levator ani muscle?

Answer 13

• the puborectalis
• the pubococcygeus
• the iliococcygeus

Question 14

Where is the perineum located?

Answer 14

• below the pelvic diaphragm

Question 15

What makes up the urogenital diaphragm?

Answer 15

• the deep and superficial transverse perineal muscles

Question 16

T or F: the urethra pierces the urogenital diaphragm, but the anal canal does not.

Answer 16

• true!

- this is because the urogenital diaphragm is present only in the anterior part of the pelvic outlet, not the posterior

Question 17

Which two muscles lie below the urogenital diaphragm?

Answer 17

• the isciocavernosus muscles and the bulbospongiosus

Question 18

Where is the pudendal canal (Alcock’s Canal)? What does it contain?

Answer 18

• on the lateral side of each ischiorectal/ischioanal fossa

- the pudendal nerve and internal pudendal vessels

Question 19

Does the vagina pierce through the pelvic diaphragm? What about the urogenital diaphragm?

Answer 19

• it pierces through both!

- as does the urethra

Question 20

Does the male urethra pierce through the pelvic diaphragm? What about the urogenital diaphragm?

Answer 20

• it pierces through both

Question 21

Does the anal canal pierce through the pelvic diaphragm? What about the urogenital diaphragm?

Answer 21

• the anal canal pierces through only the pelvic diaphragm

Question 22

At what point does the rectum become the anal canal?

Answer 22

• at the anorectal junction

Question 23

Which part of the levator ani is involved in defecation?

Answer 23

• the puborectalis muscle

Question 24

In males, what is the space/pouch of the peritoneal cavity between the rectum and the bladder known as? What about in females?

Answer 24

• males: rectovesical pouch

- females: rectouterine pouch (pouch of Douglas), because the uterus is located here

Question 25

The “grooved” portion inside the anal canal that separates the rectum from the anus is known as the:

Answer 25

• pectinate line

- it “separates” the visceral from the parietal

Question 26

What does each anal column (the anal columns make up the pectinate line) contain?

Answer 26

• a small artery and vein

- this is where hemorrhoids can form

Question 27

Lymphatic drainage above the pectinate line mainly goes to which nodes?

Answer 27

• the internal iliac nodes or the nodes near the inferior mesenteric vessels

Question 28

Lymphatic drainage below the pectinate line mainly goes to which nodes?

Answer 28

• the inguinal nodes

Question 29

The internal anal sphincter is made up of _________; the external sphincter is made up of __________.

Answer 29

• internal: smooth muscle

- external: skeletal muscle

Question 30

Which 4 arteries supply the lower rectum and the anal canal? Where do they originate from?

Answer 30

• superior rectal arteries (from the inferior mesenteric)
• middle rectal arteries (from the internal iliac)
• inferior rectal arteries (from the internal pudendal)
• median sacral artery

Question 31

What is the main arterial supply to the pelvis and its organs?

Answer 31

• the internal iliac arteries and its branches

Question 32

What are the two main branches of the internal iliac artery?

Answer 32

• the posterior division and the anterior division

Question 33

Which arterial branches arise from the posterior division of the internal iliac?

Answer 33

• iliolumbar, lateral sacral, and superior gluteal

Question 34

Which arterial branches arise from the anterior division of the internal iliac?

Answer 34

• umbilical, superior & inferior vesical, obturator, middle rectal, uterine & vaginal, internal pudendal, and inferior gluteal

Question 35

T or F: the entire pelvic diaphragm is normally in a tonic/contracted state.

Answer 35

• true!

- they are in this contracted state via slow twitch muscle fibers

Question 36

Where does the main nerve supply of the pelvic diaphragm come from?

Answer 36

• S2, S3, & S4

- “S2, 3, 4 keeps your asshole off the floor”