clinical anatomy of anaesthesia for labour

Question 1

reproductive system has two types of nerve innervation?

Answer 1

• motor
• sensory

Question 2

motor function of repro system

Answer 2

• uterine ‘cramping’ during constriction
• uterine contraction during labour
• pelvic floor muscle contraction during sneezing

Question 3

sensory function of repro system

Answer 3

• pain from adnexae - ovaries and fallopian tubes
• pain from uterus
• pain from vagina
• pain from perineum

Question 4

if structure is in pelvis i.e. body cavity nerve supply from?

Answer 4

• sympathetic
• parasympathetic
• visceral afferent

Question 5

if structure is in perineum i.e. body wall where is nerve supply from?

Answer 5

• somatic motor and somatic sensory

Question 6

what is above levator ani muscle

Answer 6

pelvis

Question 7

what is below levator ani muscle

Answer 7

perineum

Question 8

uterine cramping and uterine contraction is controlled by

Answer 8

• sympathetic/parasympathetic driven by hormones

Question 9

pelvic floor muscle contraction is controlled by?

Answer 9

• somatic motor

Question 10

pain from adnexae is from?

Answer 10

• visceral afferents

Question 11

pain from uterus is from?

Answer 11

• visceral afferents

Question 12

pain from vagina is from?

Answer 12

• visceral afferents (pelvic part)/somatic sensory (perineum)
  > different as vagina is both above and below pelvic floor

Question 13

pain from perineum?

Answer 13

• somatic sensory

Question 14

peritoneum drapes over superior pelvic organs, so pain from superior aspect of pelvis travel in visceral afferent fibres that run alongside?

Answer 14

• sympathetic fibres
• enter spinal cord between T11-L2

Question 15

pain is perceived from superior aspect of pelvic organs as?

Answer 15

• suprapubic

Question 16

inferior aspect of pelvic organs/not touching peritoneum how does pain travel?

Answer 16

• travels along visceral afferents running alongside parasympathetic fibres
• enter spinal cord at levels S2, S3, S4

Question 17

pain from inferior aspect of pelvic organs is percieved where?

Answer 17

• S2, S3, S4 dermatome (perineum)

Question 18

pain from structures above levator ani - in the pelvis travel how?

Answer 18

• along visceral afferents
• run alongside parasympaethic fibes
• enter spinal cord levels at S2, S3, S4

Question 19

pain from structures below levator ani - in the perineum (body wall) travel how?

Answer 19

• along somatic sensory fibres
• as part of pudendal nerve
• enter spinal cord levels S2, S3 and S4
• localised pain within perineum

Question 20

sympathetic nerves travel down what?

Answer 20

• sacral sympaethic trunks
• T11-L2
• form superior hypogastric plexus
• • provide visceral motor innervation

Question 21

parasympathetic nerves originate form where?

Answer 21

• originate from sacral outflow (S2,3,4)
• emerge from spinal roots
• mix with sympathetics in inferior hypogastric plexus

Question 22

parasympathetic nerves travel in what?

Answer 22

• pelvic splanchnic nerves

Question 23

pain from female repro system - two important spinal cord levels are:

Answer 23

• T11-L2
• S2-S4

Question 24

peritoneum touches bottom of uterus/sup aspect of vagina

Question 25

levator ani separates divisions of what

Answer 25

- pelvis and perineum - everything below = perineum - everything above = pelvis

Question 26

which pelvic organs touch peritoneum

Answer 26

- uterine tubes, uterus, ovaries - travel via sympathetic fibres - T11 - L2

Question 27

which pelvic organs are inferior to peritoneum

Answer 27

- cervix, and superior vagina - travel via parasympathetic fibres - S2, S3 and S4

Question 28

in perineum - ie below level of levator ani - inferior vagina, perineal muscles, glands and skin what is nerve information travelling by?

Answer 28

- somatic sensory information carried back in pudendal nerve - to S2, S3 and S4

Question 29

study flow diagram

Answer 29

Question 30

spinal cord becomes cauda equina at what level?

Answer 30

- L2 vertebra

Question 31

subarachnoid space ends at level of ?

Answer 31

- S2

Question 32

anaesthetic is injected into which level?

Answer 32

- L3-L4 (L5) region - intercristal plane determines levels of L4 spinous process (most superior point on iliac crests) however variety in intercritsal planes and should be careful when doing this

Question 33

epidural needs to pass through which structures?

Answer 33

- interspinous ligament (runs between spinous processes) - supraspinous ligament (run sup aspect of spinous processes) - ligamentum flavum (makes popping sound) -> loss of resistance and has entered epidural space (fat and veins) - bathes spinal roots in anaesthetic

Question 34

spinal anaesthetic: needle passes through?

Answer 34

- supraspinous lig - interspinous - lig flavum - epidural space - dura mater - arachnoid mater - finally reaches SAS (between arachnoid and pia) contains CSF - spinal anaesthetic is delivered here into CSF

Question 35

all spinal nerves and their named nerves contain what?

Answer 35

- sympathetic fibres

Question 36

sympathetic fibres supply?

Answer 36

- all arterioles > thus blockade to sympathetic fibres blocks sympathetic tone to all arterioles in lower limb causing = vasodilation

Question 37

what is risk of spinal anaesthetic to lower limb?

Answer 37

- vasodilation - flushed, reduced sweating, warm lower limb - hypotension can be caused - patient should be closely observed during this procedure

Question 38

sympathetic fibres originate from where?

Answer 38

- arise form autonomic control centres of brain - exit spinal cord with T1-L2 spinal nerves - travel to sympathetic chains/trunks which make up whole vertebral column - pass into all spinal nerves and ant and post rami or named nerves

Question 39

below L2 level sympathetic ganglia receive fibres from what level?

Answer 39

- from L2 level via sympathetic chain - distribute them via connections w lumbar, sacral and coccygeal spinal nerves

Question 40

the pudendal nerve has what functions

Answer 40

- somatic nerve carrying somatic motor and sensory fibres and is known as nerve of perineum - role in motor control of external anal and external urethral sphincters

Question 41

where is pudendal nerve dervied from?

Answer 41

- branch of sacral plexus - S2, S3, S4

Question 42

where is pudendal nerve derived from?

Answer 42

- branch of sacral plexus - S2, S3, S4

Question 43

pudendal nerve exists pelvis via what?

Answer 43

- greater sciatic foramen - and passes posterior to sacrospinous ligament (near ischial spine - its attachment site) - re-enters pelvis/perineum via lesser sciatic foramen - travels in pudenal canal - branches to supply structures of perineum

Question 44

the pudendal nerve crosses posteiror to lateral aspect of what?

Answer 44

- sacrospinous ligament

Question 45

what part of pelvis can be used as a landmark for pudendal nerve block?

Answer 45

- ischial spine

Question 46

when is pudendal nerve block administered?

Answer 46

- forceps delivery - painful vaginal delivery - episiotomy incision -> also post delivery for perineal suturing

Question 47

during labour branches of what nerve can be stretched?

Answer 47

- pudendal nerve

Question 48

what fibres and muscle can be torn also during lavour?

Answer 48

- fibres within levator ani (puborectalis) - external anal sphincter muscle could be torn

Question 49

1st degree tear during labour

Answer 49

- skin 2nd degree - perineal muscles 3rd degree - partial anal sphincter involvement 4th degree - complete anal sphincter tear and bowel lining and weakened pelvic floor and fecal incontinence

Question 50

what is an episiotomy?

Answer 50

- an incision into skin and perineal muscles - incision is posterolateral incision into fat filled ischioanal fossa - aim of this incision is to avoid any tearing or incision going towards anal sphincter