Bony Pelvis and Pelvic Wall

Question 1

How can you tell if the sacrum is in anatomical position?

Answer 1

ASIS and anterior pubis are in the same vertical plane

Question 2

When do the ilium, ischium, and pubis fuse?

Answer 2

puberty

Question 3

Who gets pelvic fractures more: children or adults?

Answer 3

adults

pelvic bones fuse at puberty, so the 3 bones are more flexible until they fuse

Question 4

What are the anatomical landmarks of the ilium?

Answer 4

• iliac crest
• iliac fossa
• anterior superior iliac spine
• anterior inferior iliac spine
• arcuate line
• iliac tuberosity
• posterior superior iliac spine
• anterior gluteal line
• posterior gluteal line

Question 5

What are the anatomical landmarks of the ischium?

Answer 5

• ischial spine
• ischial body
• ischial tuberosity
• ischial ramus

Question 6

What are the anatomical landmarks of the pubis?

Answer 6

• superior pubic ramus
• pectineal line
• pubic tubercle
• pubis, body
• symphyseal surface
• inferior pubic ramus

Question 7

What ligament(s) are between the sacrum and ilium?

Answer 7

anterior sacroiliac L

posterior sacroiliac L

Question 8

What are the functions of the sacrospinous L and sacrotuberous L?

Answer 8

prevent rotation of sacrum and coccyx

Question 9

What is the other name for the greater pelvis?

Answer 9

false pelvis

Question 10

What is the other name for the lesser pelvis?

Answer 10

true pelvis

Question 11

What type of compression fracture causes multiple breaks?

Answer 11

anterior posterior compression - car accident

Question 12

What type of fracture causes fracture of acetabulum?

Answer 12

lateral compression

Question 13

What are the weak points of the pelvis?

Answer 13

• pubic rami
• acetabulum
• sacroiliac joints
• iliac ala

Question 14

What is the male pelvis called?

Answer 14

android pelvis

Question 15

What is the female pelvis called?

Answer 15

gynecoid pelvis

Question 16

Desccribe the android pelvis

• general
• greater pelvis
• lesser pelvis
• pelvic inlet
• pelvic outlet
• pubic arch/angle
• obturator foramen
• acetabulum
• greater sciatic notch

Answer 16

• general: thick and heavy
• greater pelvis: deeper
• lesser pelvis: narrow and deep
• pelvic inlet: heart shaped
• pelvic outlet: smaller
• pubic arch/angle: <70 degrees
• obturator foramen: round
• acetabulum: large
• greater sciatic notch: narrow ~70 degrees

Question 17

Decribe the gynecoid pelvis

• general
• greater pelvis
• lesser pelvis
• pelvic inlet
• pelvic outlet
• pubic arch/angle
• obturator foramen
• acetabulum
• greater sciatic notch

Answer 17

• general: thin and light
• greater pelvis: shallow
• lesser pelvis: wide and shallow
• pelvic inlet: oval, cylindrical, wide
• pelvic outlet: larger (wider)
• pubic arch/angle: wide > 80 degree
• obturator foramen: oval
• acetabulum: small
• greater sciatic notch: large ~90 degrees

Question 18

What does the greater pelvis contain?

Answer 18

abdominal viscera

Question 19

What contains the lesser pelvis?

Answer 19

pelvic bones

Question 20

What is the other name for the pelvic inlet?

Answer 20

superior aperture

Question 21

What is the other name for the pelvic outlet?

Answer 21

inferior aperture

Question 22

What are the main pelvic wall muscles?

Answer 22

• piriformis
• obturator internus
• coccygeus

Question 23

What muscles work together to laterally rotate the thigh?

Answer 23

obturator internus and piriformis

Question 24

Where does the obturator internus attach?

Answer 24

greater trochanter

Question 25

Where does the piriformis attach?

Answer 25

greater trochanter

Question 26

What is the action of the piriformis?

Answer 26

laterally rotate the thigh

Question 27

What is the action of the obturator internus?

Answer 27

laterally rotate the thigh

Question 28

What is the function of the coccygeus m?

Answer 28

supports pelvic viscera and flexes coccyx

Question 29

The pelvic floor is also the ____

Answer 29

roof of the peritoneum

Question 30

What are the pelvic floor muscles?

Answer 30

coccygeus iliococcygeus pubococcygeus puborectalis

Question 31

What are the levator ani function?

Answer 31

elevate the anal canal

Question 32

What is the tendinous arch of levator ani?

Answer 32

thickening of obturator internus fascia between ischial spine and pubic body

Question 33

What does the tendinous arch of the levator ani divide?

Answer 33

obturator internus m into superior pelvic region and inferior perineal portion

Question 34

What is the anorectal angle created by?

Answer 34

puborectalis m

Question 35

What is the function of the anorectal angle created by the puborectalis m?

Answer 35

helps maintain fecal continence - will relax during urination and defecation - works independently from sphincters

Question 36

What are the levator hiatus?

Answer 36

openings created by pelvic floor muscles - anterior gap in levator ani muscles - passageway for the urethra, rectum, and vagina - anteromedial fibers of pubococcygeus and puborectalis

Question 37

What is the order of the levator ani from medial to lateral?

Answer 37

puborectalis pubococcygeus iliococcygeus

Question 38

What are the most susceptible muscle to tear during childbirth?

Answer 38

puborectalis m | pubococcygeus m

Question 39

What is the ischiorectal fossa filled with?

Answer 39

fat, neurovasculature

Question 40

What is the function of the ischio-anal fossae?

Answer 40

allows movement of pelvic diaphragm and expansion of anal canal

Question 41

What are the triangles of the ischial-anal fossae?

Answer 41

urogenital triangle and anal triangle (front and back)

Question 42

What are the two flexures?

Answer 42

- sacral flexure/dorsal bend | - anorectal flexure/ventral bend/perineal flexure

Question 43

What is the dorsal bend due to?

Answer 43

concave form of sacrum

Question 44

What is the ventral bend due to?

Answer 44

encirclement of the rectum by the levator ani (puborectal sling) -point where rectum transitions to anal canal

Question 45

What are the parts of the anal canal?

Answer 45

- anal columns - anal valves - anal sinuses - external anal sphincter - internal anal sphincter - pectinate line

Question 46

What are anal columns?

Answer 46

longitudinal ridges

Question 47

What are anal valves?

Answer 47

folds at the base of the columns

Question 48

What are anal sinuses?

Answer 48

adjacent to valves | -secrete mucus to facilitate defication

Question 49

What are the parts of the external anal sphincter?

Answer 49

- subcutaneous - superficial - deep

Question 50

What percent of anal tone is the external anal sphincter doing?

Answer 50

15-30%

Question 51

What percent of anal tone is the internal anal sphincter doing?

Answer 51

55-85%

Question 52

What type of muscle is the external anal sphincter?

Answer 52

skeletal

Question 53

Is the external anal sphincter voluntary or involuntary?

Answer 53

voluntary

Question 54

What type of muscle is the internal anal sphincter?

Answer 54

circular smooth m

Question 55

Is the internal anal sphincter voluntary or involuntary?

Answer 55

involuntary

Question 56

What is the function of the internal anal sphincter?

Answer 56

tonic contraction except when feces fill rectum

Question 57

What does the pectinate line divide?

Answer 57

upper 2/3 anal canal from lower 1/3 anal canal

Question 58

Above pectinate line | -embryological origin

Answer 58

endoderm

Question 59

below pectinate line | -embryological origin

Answer 59

ectoderm

Question 60

above pectinate line - nerves - veins - hemorrhoid classification - destination of lymph

Answer 60

- nerves: inferior hypogastric plexus (visceral - mixed symp and para) - veins: superior rectal v (portal) - hemorrhoid classification: internal (not painful) - destination of lymph: internal iliac lymph nodes, inferior mesenteric

Question 61

below pectinate line - nerves - veins - hemorrhoid classification - destination of lymph

Answer 61

- nerves: inferior rectal N (somatic) - veins: inferior rectal v (systemic) - hemorrhoid classification: external (painful) - destination of lymph: superficial inguinal lymph nodes

Question 62

describe internal hemorrhoid

Answer 62

- above pectinate line - bright red blood - not painful - prolapsed rectal mucosa due to weakened muscularis mucosa and abundant arteriovenous anastamosis

Question 63

describe external hemorrhoids

Answer 63

- below pectinate line - painful: hurts when wiping - external venous plexus covered with epidermis

Question 64

What are hemorrhoids a consequence of?

Answer 64

portal hypertension

Question 65

describe the lymph drainage | -superior rectum

Answer 65

superior rectum --> pararectal lymph nodes --> sacral lymph nodes --> inferior mesenteric lymph nodes

Question 66

describe lymph drainage | -inferior rectum

Answer 66

inferior rectum --> internal iliac lymph nodes

Question 67

describe lymph drainage | -anal canal (below pectinate line)

Answer 67

anal canal--> superficial lymph nodes