Pelvis Osteology, Ligaments and Muscles

Question 1

What are the 3 parts that make up the bony pelvis?

Answer 1

Hip bone
Sacrum
Coccyx

Question 2

What are the parts of the hip bone?

Answer 2

Ischium
Ilium
Pubis

Question 3

How are the 2 hip bones jointed anteriorly and posteriorly?

Answer 3

Anteriorly joined by pubic symphysis

Posteriorly joined by sarum

Question 4

Where do the ilium, ischium and pubis fuse?

Answer 4

Acetabulum - where head of femur articulates with hip

Question 5

What is the sacrum? What does it form?

Answer 5

Large bone located at the terminal part of the vertebral canal
Itt forms the posterior aspect of the pelvis

Question 6

What is the sacrum formed from?

Answer 6

The fusion of the 5 sacral vertebrae

Question 7

What are the surfaces of the sacrum?

Answer 7

Base
Apex 
Auricular (lateral)
Anterior 
Posterior

Question 8

What does the pelvic inlet mark? What is it defined by?

Answer 8

The boundary between the greater and lesser pelvis

It is defined by its edge, the pelvic brim

Question 9

What are the borders of the pelvic inlet?

Answer 9

Anterior - pubic symphysis
Posterior - sacral promontory
Lateral - iliopectineal line

Question 10

What does the pelvic inlet determine?

Answer 10

Determines the size and shape of the brith canal

Question 11

What are the borders of the pelvic outlet?

Answer 11

Anterior - pubic arch
Posterior - tip of coccyx
Lateral - ischial tuberosities and inferior margin of sacrospinous ligament

Question 12

Which is the false and which is the true pelvis?

Answer 12

True - lesser pelvis

False - greater pelvis

Question 13

Where is the true pelvis and what does it contain?

Answer 13

Between the pelvic inlet and outlet

It contains the bladder, reproductive organs and the ischioanal fossae

Question 14

Where is the false pelvis and what does it contain?

Answer 14

Above the pelvic inlet

It contains abdominal viscera eg. ileum and sigmoid colon

Question 15

What shape is the pelvic inlet in men? What shape is it in women?

Answer 15

Heart shape

Oval shape in women

Question 16

What is the difference in shape of a women’s plevis compared to a man’s?

Answer 16

Woman’s plevis wider and broader structure but flatter and lighter in weight

Question 17

What has a greater angle in a woman’s pelvis than a man’s?

Answer 17

Sub-pubic arch

Question 18

What is the greater sciatic foramen?

Answer 18

Foramen within pelvis

Is a major channel for neurovascular structures to pass from the pelvis to the lower limb

Question 19

What are the superior, inferior, posteromedial and anterolateral boundaries of the greater sciatic foramen?

Answer 19

Superior - anterior sacroiliac ligament
Inferior - sacrospinous ligament
Posteromedial - sacrotuberous ligament
Anterolateral - greater sciatic notch

Question 20

What are 4 vessels that pass through the greater sciatic foramen?

Answer 20

Superior and inferior gluteal muscles
Internal pudenal vessels
Gluteal nerves
Nerves of the sacral plexus

Question 21

Where is the lesser sciatic foramen?

Answer 21

Between the sacrotuberous and sacrospinous ligaments

Question 22

What are the 3 boundaries of the lesser sciatic foramen?

Answer 22

Sacrotuberous ligament
Sacrospinous ligament
Lesser sciatic notch

Question 23

Where does the sacrospinous liagment run from? What does it form?

Answer 23

Sacrospinous ligament runs from the ischial spine to the sacrum
It forms the base of the greater and lesser sciatic foramen

Question 24

Where does the sacrotuberous ligament run from? What does it form?

Answer 24

Sacrotuberous ligament runs from the sacrum to the tuberosity of the ischium
It forms the boundary of the greater and lesser sciatic foramen

Question 25

Where does the inguinal ligament run from?

Answer 25

From the ASIS to the pubic tubercle

Question 26

Where does the sacroiliac ligament run?

Answer 26

From sacrum to ilium

Question 27

What is the obturator?

Answer 27

A thin sheet which closes the obturator foramen

Question 28

What is the linea termialis/ pubic brim made of? | What edge is it?

Answer 28

``` Pubic crest Pecten pubis/ pectineal line Arcuate line Sacral ala Sacral promontory It is the edge of the pelvic inlet ```

Question 29

Where is the conjugate measurement taken from? What is the average?

Answer 29

Between sacral promontory and the edge of the pubic symphysis Average of 11cm

Question 30

Where is the transverse measurement taken from?

Answer 30

Between the ischial tuberositites

Question 31

Where is the oblique measurement taken from? | What is the average

Answer 31

``` Sacroilial joint (SIJ) to iliopubic eminence Average 12cm ```

Question 32

Where is the interspinous measurement taken from? Why is this significant?

Answer 32

Measured between the ischial spines | Significant as this is the narrowest part of the pelvic canal

Question 33

What is the pelvis floor made from? (3 things)

Answer 33

Lavator ani muscle Coccygeus muscle Fascia coverings of these muscles

Question 34

What are the levator ani?

Answer 34

3 paired muscles: Pubococcygeus Puborectalis Iliococcygeus

Question 35

What is the innervation of levator ani muscles? What are the nerve roots?

Answer 35

Pudenal nerve | S2-4

Question 36

What are the actions of the levator ani muscles? (3 things)

Answer 36

Support the abdominopelvic viscera through their tonic contraction Urinary and fecal continence Provide resistance to increase in intrapelvic/ abdominal pressure during eg. coughing or lifting heavy objects

Question 37

What is the origin and insertion of the coccygeus muscle?

Answer 37

Origin - ischial spine | Insertion - lateral aspect of sacrum and coccyx

Question 38

What does the external anal sphincter blend with superiorly?

Answer 38

The puborectalis muscle of the pelvic floor

Question 39

Where is the anorectal ring?

Answer 39

At the junction of the rectum and anal canal

Question 40

What forms the anorectal ring?

Answer 40

Fusion of internal and external anal sphincters and the puborectalis muscle