Anaesthesia of Labour

Question 1

what is the function of the female reproductive motor system

Answer 1

uterine ‘cramping’ - menstruation

Uterine contraction (eg. labour)

Pelvic floor muscle contraction eg. during sneezing

Question 2

what is the functions of the female reproductive sensory system

Answer 2

Pain from the adnexae (ovaries+ Fallopian tubes)

Pain from uterus

Pain from vagina

Pain from perineum

Question 3

what nerves innervate structures in the pelvis

Answer 3

Sympathetic
Parasympathetic
Visceral afferent

(as it is a body cavity)

Question 4

what nerves innervate structures in the perineum

Answer 4

somatic motor
somatic sensory

(body wall)

Question 5

what do parasympathetic and sympathetic nerves to the uterus control

Answer 5

uterine ‘cramping’ - menstruation

Uterine contraction - labour

Question 6

what do somatic motor nerves to the female reproductive system control

Answer 6

pelvic floor muscle contraction

Question 7

what pain do visceral afferents to the female reproductive system sense

Answer 7

pain from adnexae (ovaries+Fallopian tubes)

Pain from uterus

pain from pelvic part of the vagina

Question 8

what female reproductive pain is sensed by somatic sensory nerves

Answer 8

perineal part of the vagina

pain from the perineum

Question 9

where is pain from the superior pelvic organs that touch the peritoneum perceived

Answer 9

suprapubic

visceral afferents run along sympathetic fibres which enter the spinal cord at T11-L2

Question 10

where is pain from the inferior aspect of the pelvic organs perceived

Answer 10

S2,3,4 dermatome (perineum)

visceral afferents run alongside parasympathetic fibres

enter spinal cord at levees S2, S3 and S4

Question 11

where is pain perceived for structures which cross the pelvis into the perineum (eg. urethra, vagina)

Answer 11

Above the elevator ani - visceral afferent, S2,3,4

Below elevator ani - pudenal nerve S2,3,4, somatic sensory

Question 12

where does sympathetic innervation to the pelvis come through

Answer 12

Sacral sympathetic trunk
T11-L2

Superior hypogastric plexus

Question 13

where does parasympathetic innervation to the pelvic organs come from

Answer 13

Pelvic splanchnic nerves
S2,3,4
emerge from spinal rotes
mix with sympathetics in the interior hypogastric plexus

Question 14

what 3 types of anaesthesia are used for the female reproductive system

Answer 14

Spinal anaesthetic
Epidural anaesthetic
Pudenal nerve block

Question 15

when does the spinal cord become the caudate Aquinas

Answer 15

L2

Question 16

what level does the subarachnoid space end at

Answer 16

S2

Question 17

what level is anaesthetic injected for spinal or epidural

Answer 17

L3-L4 region

Question 18

how do you work out where the L4 spinous process is

Answer 18

lies just above the most superior point of the iliac crests

Question 19

what layers does the needed pass through for an epidural anaesthetic

Answer 19

supraspinous ligament
interspinous ligament
ligamentum flavum
epidural space (fat and veins)

Question 20

what layers does the needle pass through for a spinal anaesthetic

Answer 20

supraspinous ligament 
interspinous ligament 
ligamentum flavum 
epidural space 
dura matter 
arachnoid matter 
finally reaches the subarachnoid space

Question 21

where do sympathetic nerves exit the spinal cord

Answer 21

T1-L2

then travel to sympathetic chains running the length of the vertebral column

pass into all spinal nerves (in the anterior and posterior rami / named nerves)

Question 22

how do sympathetic nerves travel further down than L2

Answer 22

sympathetic ganglia receive fibres from L2 via the sympathetic chain and distribute them via connections with lumbar, sacral and coccygeal spinal nerves

Question 23

why are flushing of lower limbs, warmer lower limbs and reduced sweating all signs that spinal anaesthetic is working

Answer 23

because it blocks sympathetic fibres in all spinal nerves

sympathetic fibres supply all arterioles (sympathetic tone)

blockade of sympathetic tone causes vasodilation

can lead to vasodilation

Question 24

what does the pudenal nerve do

Answer 24

provides somatic motor and somatic sensory innervation to the structures of the perineum

motor control of external anal and external urethral sphincters

comes from S2,3,4 (sacral plexus)

Question 25

what does a pudenal nerve block do

Answer 25

anaesthetises the majority of the perineum

Question 26

where does the pudenal nerve exit the pelvis then re-enter the pelvis/perineum

Answer 26

exits - greater sciatic foramen

re-enters- loser sciatic foramen

Question 27

what does the pudenal nerve travel in

Answer 27

the pudenal canal

passageway within obturator fascia

travels with internal pudenal artery and vein

Question 28

what landmark can be used to locate the pudenal nerve

Answer 28

ischial spine - located via internal vaginal examination

pudenal nerve runs along the lateral aspect of the sacrospinous ligament (ends at the ischial spine)

Question 29

when is a pudenal nerve block used

Answer 29

can be used during labour

• forceps delivery
• painful vaginal delivery
• episiotomy inscision

perineal suturing post delivery

Question 30

how can labour effect the pudenal nerve and perineal structures

Answer 30

branches can be stretched leading to weakness

fibres within the elevator ani or external anal spinchtor can be torn and cause muscle weakness

can lead to faecal incontinence and weakened pelvic floor

Question 31

what is an episiotomy

Answer 31

a posterolateral incision

made into the ‘safe; fat filled ischoanal fossa to avoid incision extending into rectum

prevents tearing of the anal spinchter during pregnancy