Anatomy - Anaesthesia for Labour

Question 1

Why is it so important to be able to identify if an organ is in the pelvis or perineum?

Is the vagina in the pelvis or perineum?

Answer 1

Vagina - perineum and pelvis (dual innervation)

Perineum - somatic motor and somatic sensory innervation

Pelvis - sympathetic, parasympathetic and visceral afferents innervation

Question 2

What splits pelvis and perineum again?

Answer 2

Levator ani

Question 3

What is the spinal cord levels assoc. with female pain?

Explain

Answer 3

T11-L2

S2-S4

Superior aspects of pelvic organs (those that touch the PERITONEUM) travel with SYMP. fibres to the T11-L2

Inferior aspects of pelvic organs and any other part of organ above elevator ani travel with PARA. fibres to S2-S4

Perineal organs are somatic sensory and travel via pudendal nerve to S2,S3,S4

Question 4

At what level is spinal and epidural anasethesia inserted?

Answer 4

L3-L4

Question 5

Describe the layers that the needle has to go through to reach the epidural space.

When they go through what layer will a ‘pop’ be felt?

How many more layers have to go through for spinal anaesthetic?

Answer 5

Supraspinous 
Interspinous
Ligamentum flavum - pop sound 
Epidural space
Dura mater 
Arachnoid mater
Subarachnoid space (CSF contained in)

Question 6

How can you tell if a lower spine spinal anasthesia is working? Explain

What complication can this lead to hence why patients have to closely monitored?

Answer 6

Lower limbs become flushed and hot to touch

Block sympathetic innervation -> no symp control of arterioles -> vasodilation

Hypotension

Question 7

How can the pudendal nerve be identified for injection?

How is that injection given?

Answer 7

Transvaginally find the ischial spines at 4 and 8 o’clock - pudendal nerve runs posteriorly to the sacrospinous ligament

Inject transvaginally into the space surrounding the ischial spine

Question 8

To avoid tear of the anal sphincter which can occur during labour what can be done?

Answer 8

Episiotomy - deliberate cut made on posterolateral direction towards fatty ischioanal fossa to encourage tear in that direction

Question 8

To avoid tear of the anal sphincter which can occur during labour what can be done?

Answer 8

Episiotomy - deliberate cut made on posterolateral direction towards fatty ischioanal fossa to encourage tear in that direction