GI Anatomy 6

Question 1

What is the perineum and what are its superior and inferior boundaries?

Answer 1

Space superficial to the pelvic floor, most made up of fat but has some important nerves and vessels running through it
Bounded superiorly by the pelvic floor and inferiorly by the skin

Question 2

What is the difference between the pelvic cavity and the greater pelvis?

Answer 2

Pelvic cavity is bounded superiorly by the pelvic inlet

Greater pelvis is the area superior to the pelvic inlet but inferior to a line joining the 2 ASIS

Question 3

What is the ischial spine?

Answer 3

Bony prominence of the pelvic bone between the greater and lesser sciatic notches

Question 4

Where is the ischial tuberoscity?

Answer 4

Bony prominence on the internal surface of the ischium

Question 5

The sacrospinous ligament runs from where to where and creates which foramen?

Answer 5

From the sacrum to the ischial spine, creates the greater sciatic foramen

Question 6

The sacrotuberous ligament runs from where to where and creates which foramen?

Answer 6

From the sacrum to the ischial tuberoscity and forms the lesser sciatic foramen

Question 7

What is the difference between the obtruator foramen and the obtruator canal?

Answer 7

Obturator foramen is the entire hole in between the ischial and the pubic rami of the pelvic bone, the obtruator foramen has a membrane lining it called the obtruator membrane which leaves a small opening in the obtruator foramen called the obtruator canal

Question 8

On what does the obtruator muscle lie?

Answer 8

Deep to the obtruator membrane

Question 9

What lies deep to the obtruator muscle?

Answer 9

The obtruator fascia

Question 10

What are the 3 functions of the pelvis?

Answer 10

1) Provide a surface for muscle attachments: muscles of the trunk and lower limb
2) Transfers the weight of the trunk to the lower limbs when standing and the ischial tuberosity when sitting
3) Protect pelvic organs and the developing embryo/foetus

Question 11

What 2 parts of the pelvis lie in the same vertical plane in anatomical position?

Answer 11

ASIS and the pubic tubercles

Question 12

What forms the lateral walls of the pelvis?

Answer 12

Obtruator muscle
Levator ani muscle
Piriformis muscle

Question 13

What forms the posterior (posterior-superior) wall of the pelvis?

Answer 13

Sacrum

Question 14

What nerves make up the sacral plexus?

Answer 14

nerves to the lower limb, pelvic splanchnics (autonomic) and pudendal nerve (somatic)

Question 15

What 3 muscles make up the levator ani muscle and which lies most medial/laterla?

Answer 15

1) Puborectalis muscle most medially
2) Pubococcygeas muscle in between
3) Ischiococcygeas muscle most laterally

Question 16

When deficating which of the levator ani muscles relaxes in particular and why does this occur?

Answer 16

Puborectalis muscle - relaxes to allow the recto-anal angle to straighten to faeces can pass out (normally the puborectalis muscle creates a sling around the anus creating an angle to prevent involuntary defecation)

Question 17

Where does the coccygeas muscle run from and to?

Answer 17

From the coccyx and sacrum to the ischial spine

Question 18

What is the perineal body?

Answer 18

Formed where the levator ani muscle converge in the midline. Fibromuscular mass at the junction between urogenital hiatus and anus
Its essential for the integrity of the pelvic floor and when this is ruptured during pregnancy (there is not a good blood supply as fibrous tissue so doesnt heal well) there is a tendency to prolapse

Question 19

What is the anococcygeal body?

Answer 19

Formed in the midline where the levator ani and coccygeas muscles converge

Question 20

How does the piriformis muscle exit the pelvic cavity?

Answer 20

Through the greater sciatic foramen

Question 21

Which way did blood flow in the umbilical artery? How many did you have and what is the remnant of this?

Answer 21

From the fetus to the mother
Have 2
Remnant is the median umbilical ligament

Question 22

Which way did the blood flow in the umbilical vein? What is the remnant of this?

Answer 22

From the mother to the fetus - remnant is the ligamentum terres in the falciform ligament