Nerves of the Pelvis

Question 1

where is the sacral plexus mainly derived from?

Answer 1

formed mainly by the anterior primary rami of the spinal nerves s1 to s4

Question 2

what also contributes to the sacral plexus in addition to s1-s4?

Answer 2

receives a contribution from L4 and L5

nerve bundle called the lumbo-sacral trunk

Question 3

what is the nerve bundle derived from L4 and L5 called?

Answer 3

the lumbo-sacral trunk

Question 4

describe the route of the major branches of the sacral plexus leaving the pelvis

Answer 4

leave the pelvis by passing through greater sciatic foramen either above or below piriformis

Question 5

what are the main nerves of the pelvis?(3)

Answer 5

• sacral plexus
  small motor nerves
• pudendal nerve

Question 6

where do the small motor nerves target?

Answer 6

the pelvic diaphragm

Question 7

what do the branches of the small motor nerves at s3 or s4 target?

Answer 7

• the coccygeal muscles

- levator ani muscles

Question 8

what is the principle nerve if the perineum?

Answer 8

the pudendal nerve

Question 9

where is the pudendal nerve derived from?

Answer 9

s2,3,4

Question 10

where does the pudendal nerve arise from and describe its path?

Answer 10

• arise from plexus just above sacrospinous ligament
• pass immediately through greater sciatic foramen
• then passes forwards on the side of obturator internus

Question 11

what do the branches of the pudendal nerve supply?

Answer 11

• anal sphincter
• muscle of urogenital diaphragm
• external genitalia

Question 12

what are the nerves of both the sympathetic and parasympathetic nervous system connected to?

Answer 12

connected to a diffuse and extensive plexus of autonomic nerves called the
“pelvis plexus”

Question 13

what are the two nerves of the sympathetic nervous system in the pelvis?

Answer 13

• hypogastric nerve

- tail (distal) end of the sympathetic trunk

Question 14

what are the nerves of the parasympathetic nervous system in the pelvis?

Answer 14

• the pelvis splanchnic nerves

Question 15

describe the route of the distal end of the sympathetic trunk

Answer 15

• enters pelvis to the deep common iliac vessels

- descends just medial to the sacral foramina

Question 16

role of the distal end of the sympathetic trunk?

Answer 16

-it gives rami communicantes to the anterior rami of the sacral nerves

Question 17

what are communicantes?

Answer 17

a nerve that connects two other nerves

Question 18

what does the hypogastric nerve often take the form of?

Answer 18

takes the form of several small nerves

Question 19

describe the hypogastric nerve

Answer 19

it is a distal continuation of the aortic plexus

Question 20

what is another name for the pelvic splanchnic nerves?

Answer 20

nervi erigentes

Question 21

what is the source of parasympathetic innervation in the pelvis?

Answer 21

the pelvic splanchnic nerves

Question 22

where do the pelvic splanchnic nerves arise from?

Answer 22

arise from s2 and s4

Question 23

describe the route of the pelvic splanchnic nerves

Answer 23

• branches out and enters pelvic plexus

- from plexus their fibres are distributed to the pelvic organs and external genitals

Question 24

what do the pelvic splanchnic nerves target?

Answer 24

-pelvic organs

external genitals