Pelvic walls

Question 1

describe the boundaries of the pelvis

Answer 1

anterior, posterior and lateral walls are bony and muscular
inferior boundary (floor) is muscular at the pelvic outlet
superior boundary at the pelvic inlet is open to the abdominal cavity

Question 2

what makes up the anterior wall of the pelvis

Answer 2

pubic bodies
pubic rami
pubic symphysis

Question 3

what makes up the posterior wall of the pelvis

Answer 3

sacrum
coccyx
piriformis

Question 4

what bones form the pelvis

Answer 4

2 innominate bones that articulate with eachother and with the sacrum

Question 5

why is the anterior part of the pelvis lighter

Answer 5

obturator foramen - less bone

Question 6

why is the obturator foramen almost completely closed

Answer 6

by obturator internus, obturator externus and obturator membrane

Question 7

what is the bony landmark between the greater and lesser sciatic notch

Answer 7

ischial spine

Question 8

the ischial spine is an important landmark for what

Answer 8

pudendal nerve

Question 9

what do the greater and lesser sciatic notches allow

Answer 9

passage of nerves, arteries, veins and muscles from the internal surface of the pelvis to the perineum and gluteal region

Question 10

how do the greater and lesser sciatic notches become foramina

Answer 10

presence of ligaments

Question 11

what kind of joint is the lumbosacral joint

Answer 11

secondary cartilaginous

Question 12

what kind of joint is the pubic symphysis

Answer 12

secondary cartilaginous

Question 13

the iliac blades provide attachment sites for what

Answer 13

iliacus anteriorly

gluteal muscles posteriorly

Question 14

the iliac crest allows attachment for what

Answer 14

muscles of the abdominal wall

Question 15

the ASIS is an attachment site for what

Answer 15

sartorius

Question 16

the AIIS is an attachment site for what

Answer 16

rectus femoris

Question 17

the ASIS and pubic tubercle are attachment sites for what

Answer 17

inguinal ligament

Question 18

the secondary cartilaginous joints at the lumbosacral joint and pubic symphysis allow what

Answer 18

cushioning of the stresses passing into the pelvis from the trunk and passing around the pelvic bowl

Question 19

the sacrum is formed from _ fused vertebrae

Answer 19

5

Question 20

the sacrum articulates with

Answer 20

L5 vertebrae, coccyx and ilia

Question 21

what is the purpose of the sacral foramina

Answer 21

sacral nerves pass through the sacral foramina to exit the vertebral column and supply structures within the pelvis and lower limb

Question 22

what are the two large ligaments that attach to the sacrum

Answer 22

sacrotuberous and sacrospinous ligaments

Question 23

where does the sacrotuberous ligament pass between

Answer 23

sacrum and ischial tuberosity

Question 24

where does the sacrospinous ligament pass between

Answer 24

sacrum and ischial spine

Question 25

the sacrotuberous and sacrospinous ligaments form the posterior boundaries of the

Answer 25

greater and lesser sciatic foramina

Question 26

how is the inguinal ligament formed

Answer 26

formed by the aponeurosis of the external oblique as it rolls over itself to create the anterior wall and floor of inguinal canal

Question 27

as well as forming the posterior boundaries of the greater and lesser sciatic foramina, what else do the sacrotuberous and sacrospinous ligaments do

Answer 27

support the posterior wall and floor of the pelvic cavity

Question 28

describe the sacroiliac joints

Answer 28

combination of plane synovial joint anteriorly and fibrous joint posteriorly

Question 29

how is the sacroiliac joint supported anteriorly

Answer 29

anterior sacroiliac ligament

Question 30

how is the sacroiliac joint supported posteriorly

Answer 30

posterior sacroiliac ligament

Question 31

describe the features of the female pelvis that increase the internal diameter compared to the male

Answer 31

- pubic angle at the pubic symphysis is wider - ischial spines do not protrude into the pelvic cavity as markedly - sacrum is flatter

Question 32

what is the term for the classic female shape at the pelvic inlet

Answer 32

gynaecoid

Question 33

what is the term for the classic male shape at the pelvic inlet

Answer 33

android

Question 34

what is the term for a more flattened pelvic inlet in the anterior-posterior direction

Answer 34

platypelloid shape

Question 35

what is the term for a wider inlet in the anterior-posterior direction

Answer 35

anthropoid (similar to the shape seen in apes)

Question 36

what are the attachments of iliacus

Answer 36

iliac fossa joints psoas to form iliopsoas inserts onto lesser trochanter of femur

Question 37

what is the function of iliacus

Answer 37

hip flexion

Question 38

what is the innervation of iliacus

Answer 38

femoral nerve

Question 39

what are the attachments of psoas

Answer 39

superficial: T12-L4 vertebral bodies and IVDs deep: L1-5 join iliacus to form iliopsoas and inserts onto lesser trochanter of femur

Question 40

what is the function of psoas

Answer 40

hip flexion bend trunk laterally (one) raise trunk from supine (both)

Question 41

what is the innervation of psoas

Answer 41

lumbar plexus direct branches L2-4 anterior rami

Question 42

what are the gluteal muscles

Answer 42

gluteus maximus, medius and minimus

Question 43

what are the attachments of the gluteus muscles

Answer 43

attach to pelvic bones but not within pelvic cavity - posterior surface of iliac blades

Question 44

the gluteal muscles act on

Answer 44

hip joint

Question 45

what muscle covers the external surface of the obturator foramen

Answer 45

obturator externus

Question 46

what are the attachments of obturator externus

Answer 46

outer surface of the obturator membrane to the trochanteric fossa of the femur

Question 47

what are the attachments of obturator internus

Answer 47

inner surface of the obturator membrane to the medial surface of the greater trochanter of the femur

Question 48

what is the function of the obturator internus

Answer 48

lateral rotation of the hip

Question 49

what is the innervation of the obturator internus

Answer 49

nerve to the obturator internus direct from sacral plexus (L5, S1)

Question 50

what muscle covers the inner surface of the obturator membrane

Answer 50

obturator internus

Question 51

describe how obturator internus attaches

Answer 51

attaches to the obturator membrane then sends its tendon through the lesser sciatic notch to reach the greater trochanter of the femur

Question 52

when seen in the gluteal region, obturator internus is a

Answer 52

tendon

Question 53

in the gluteal region, obturator internus is closely associated with

Answer 53

the superior and inferior gemelli muscles that lie either side of the tendon of obturator internus

Question 54

the thickened fascia above obturator internus provides an attachment site for the

Answer 54

iliococcygeus part of levator ani muscles that form the pelvic floor

Question 55

the obturator internus also acts to support

Answer 55

the lateral pelvic wall covering the opening of the obturator foramen

Question 56

what are the attachments of piriformis

Answer 56

pelvic surface of the sacrum then passes through greater sciatic foramen to the greater trochanter of the femur

Question 57

what is the function of piriformis

Answer 57

lateral rotation of the hip joint

Question 58

what is the innervation of piriformis

Answer 58

nerve to piriformis direct branch of sacral plexus (S1, S2)

Question 59

piriformis is a useful landmark inside the pelvis for what

Answer 59

useful landmark inside the pelvis as the sciatic nerve and pudendal nerve form on its superior surface

Question 60

piriformis is a useful landmark in the gluteal region for what

Answer 60

superior and inferior gluteal nerves and vessels lie either side of piriformis and the sciatic nerve descends from the greater sciatic notch beneath it

Question 61

piriformis also acts to support

Answer 61

the pelvic wall by partially covering the opening of the greater sciatic foramen