T2 L10, Anatomy of the pelvic region

Question 1

What bones make up the pelvis?

Answer 1

2 innominate (hip) bones formed of the ilium, ischium, and pubis

A sacrum formed by the fusion of the 5 sacral vertebrae

A Coccyx formed by the fusion of the 4 coccygeal vertebrae

Question 2

Name the pelvic joints

Answer 2

Sacro-iliac joints, a secondary cartilaginous disc (posterior)

Pubic symphysis, a fibrocartilaginous disc (anterior)

Question 3

Where in the pelvis is weight transferred to when standing?

Answer 3

From the axial skeleton to the ilia via ligaments to the femur

Question 4

Where in the pelvis is the weight transferred to when sitting?

Answer 4

To the ischial tuberosities

Question 5

What is the pelvic brim?

Answer 5

The bony edges defining the pelvis

Question 6

What forms the pelvic brim?

Answer 6

Promontory and ala (wing) of sacrum

The arcuate line (Inner surface of the ilium)

Pectineal line (Superior ramus and body of the pubis

Question 7

What is the true pelvis vs the false pelvis?

Answer 7

The false pelvis is superior (superior pelvis) and is surrounded by iliac fossa portions of the coccygeal bones and the upper portion of the sacrum

The true pelvis is inferior (inferior pelvis) and is surrounded by the pubis and ischium portions of the coccygeal bones

Question 8

Where is the sacroiliac ligament?

Answer 8

Between the sacrum and the ilium. It has an anterior and posterior component

Question 9

Where is the sacrococcygeal ligament?

Answer 9

Between the sacrum and the coccyx

Question 10

Where is the sacrospinous ligament?

Answer 10

Between the ischial spine and sacrum/coccyx

Question 11

Where is the sacrotuberous ligament?

Answer 11

It’s posterior to the sacrospinous, between the lateral aspect of the coccyx onto medial margin of ischial tuberosity. It creates the sciatic foramen

Question 12

What are some sex differences of the pelvis?

Answer 12

• Male is thicker and heavier
• The greater pelvis is shallower in females
• The lesser pelvis is narrow and deep in males and wide and shallow in females
• The pelvic inlet is heart shaped in males and oral in women
• The pubic arch is wider in females
• In males, the obturator foramen is round, in females it’s oval
• The acetabulum is smaller in females

Question 13

What does the greater pelvis contain?

Answer 13

The abdominal viscera

Question 14

What does the lesser pelvis contain?

Answer 14

The reproductive, urinary, and GI organs

Question 15

What does the obturator internus muscle do?

Answer 15

It rotates the thigh internally

Question 16

What is the obturator foramen for?

Answer 16

To allow passage of the obturator nerve, artery, and vein

Question 17

What does the piriformis muscle do?

Answer 17

Rotates the thigh internally and abducts the thigh

Question 18

What is the pelvic floor formed of?

Answer 18

The pelvic diaphragm consisting of the coccygeus (ischiococcygeaus) and levator ani muscles

Question 19

What is the function of the pelvic floor?

Answer 19

To support the pelvic viscera

They resist rises in pressure when we cough

Question 20

What is the Levator Ani formed of?

Answer 20

Puborectalis, Pubococcygeus, Iliococcygeus

Question 21

Which spinal vertebrae innervates the Levator Ani?

Answer 21

S4

Question 22

What happens when the Puborectalis muscle relaxes?

Answer 22

Allow for defecation

Question 23

What is the perineum?

Answer 23

The space between the genital outlet ands the anus. It’s the convergence of several sphincter and perineal pouch muscles

The transverse lines there splits the 2 ischial tuberosities into the urinary and anal triangles

Question 24

Why do males have a longer gonadal artery?

Answer 24

Because the testes are outside of the body

Question 25

Which artery provides the main blood supply to the pelvis?

Answer 25

The internal iliac artery that splits from the aorta

Question 26

Which vein mainly drains the pelvis?

Answer 26

The internal iliac to the common iliac veins

Question 27

What is contained within the anterior division of the internal iliac artery?

Answer 27

Umbilical artery 
Obturator artery 
Superior visceral artery 
Inferior vesical/vaginal artery 
Uterine artery 
Middle rectal
Internal pudendal
Inferior gluteal

Question 28

What is contained within the posterior division of the internal iliac artery?

Answer 28

Iliolumbar artery
Lateral sacral artery
Superior gluteal artery

Ovarian artery from Aorta
Medial sacral artery from the abdominal Aorta
Superior rectal artery from the inferior mesenteric

Question 29

Which nerves innervate the pelvis?

Answer 29

The sacral and coccygeal nerves and part of the autonomic NS

They all function as motor or sensory

Question 30

What is the somatic plexus divided into?

Answer 30

The lumbarsacral L4-S4 and coccygeal (S4-Co)

Question 31

Where is the sacral plexus located?

Answer 31

On the posterolateral wall of the lesser pelvis

Question 32

What are the main nerves of the sacral plexus?

Answer 32

Sciatic nerve
Pudendal nerve
Superior gluteal nerve
Inferior gluteal nerve

Question 33

What does the sciatic nerve supply?

Answer 33

The leg and foot

Question 34

What does the Pudendal nerve supply?

Answer 34

Sensory info to the genitalia, muscular branches to the perineal muscles, external urethral sphincter, and the external anal sphincter

It gives rise to the inferior rectal, perineal branches, posterior scrotal/labial branches, and dorsal nerve to the penis/clitoris

Question 35

What does the Superior gluteal nerve supply?

Answer 35

The gluteal region

Question 36

What does the Inferior gluteal nerve supply?

Answer 36

The gluteal region

Question 37

Why is the Pudendal nerve known as the perineal nerve now?

Answer 37

Because pudendal nerve means shamed and they want to change that

Question 38

What is the significance of the pelvic pain line?

Answer 38

Pain above it will be referred to the abdomen

Question 39

Which nerves provide parasympathetic flow to the pelvis?

Answer 39

Pelvic splanchnic nerves S2-4

Question 40

Which nerves provide sympathetic flow to the pelvis?

Answer 40

The sacral sympathetic trunk and superior and inferior hypogastric plexuses