Anatomy of Labour and Surgical Incisions

Question 1

what is the pelvic pain line

Answer 1

a threshold that determines the (afferent) course of visceral pain sensation

structures above the line (assoicated with the peritoneum) convey visceral pain sensation via sympathetic splanchnic nerves

structures below the line convey visceral pain sensation via parasympathetic splanchnic nerves

Question 2

can organs refer pain via sympathetic and parasympathetic afferent fibres

Answer 2

yes, they can cross the pelvic pain line

Question 3

where is pain from above the pelvic pain line perceived

Answer 3

as suprapubic (T11-L2 dermatome)- travelling in synmpathetic fibres and enters the spinal cord a these levels (sympa is a thoracolumbar outflow)

Question 4

where is pain from below the pelvic pain line perceived

Answer 4

perineum - enters spinal cord at S2-4 after travelling with parasympathetic fibres

Question 5

how is pain referred from structures that cross from the pelvis (below pelvic pain line) to perineum, eg urethra, vagina

Answer 5

the levator ani forms the pelvic floor, structures above are in the pelvis and below are in the perineum

structures above refer pain through parasympathetic fibres, below is somatis sensory innervation with the pudendal nerve

Question 6

how is pain from the perineum perceived

Answer 6

localised pain in perineum - pudendal nerve (somatic sensory)

Question 7

motor supply to levator ani

Answer 7

pudendal nerve and nerve to elvator ani (branches of sacral plexus)

Question 8

outline the pathway of the pudendal nerve

Answer 8

• Leaves pelvis through greater sciatic foramen and re-enters through lesser sciatic foramen
• Wraps around ischial spine
• Now accompanied internal pudendal artery and vein through pudendal canal (Alcock’s canal – formed by fasica of obturator internus muscle)

Nerve gives off branches inside the canal

Question 9

what is the pudendal canal formed from

Answer 9

fascia from the obturator internus

Question 10

what is the clinical signficance of teh pudendal nerve being fixed in the canal

Answer 10

can get stretched or pulled eg during childbirth

Question 11

outline the procedure for a pudendal nerve block

Answer 11

A pudendal nerve block is a form of analgesia occasionally given before vaginal childbirth, episiotomy and other minor vaginal procedures.

To administer a pudendal nerve block, the patient is placed in the lithotomy position, and the ischial spine is palpated transvaginally. Local anaesthetic is then injected into the tissues around the ischial spine. The procedure is then completed on the opposite side.

As the pudendal nerve is accompanied by the internal pudendal artery, it is essential to aspirate before injecting local anaesthetic – this ensures that local anaesthetic is not administered into the systemic circulation.

Question 12

which nerve block is used if you want to stop the pain fromuterine contractions?

Answer 12

spinal anaesthesia - will anaesthetise everything from the waist down

Question 13

what problems with arterioles does spinal anaesthesia also cause

Answer 13

as the basal vascular tone of arterioles is caused by the sympathetic system –> vasodilation –> flushed skin, warmth, reduced sweating –> hypotension

Question 14

which additional nerve block is required to anaesthetise the anterior labia

Answer 14

ilioinguinal nerve

Question 15

what major structure can be damaged in a median episiotomy

Answer 15

external anal sphincter –> faecal incontinence

Question 16

which lines must you try to follow when making an incision

Answer 16

Langer lines - lines of skin tension

Question 17

what are teh 2 layers of superficial fascia

Answer 17

campers fascia - outer fatty layer

scarpas fascia - inner membranous layer

Question 18

outline the layers of the anterolateral abdominal wall

Answer 18

Question 19

what is an aponeurosis

Answer 19

a flat, sheet like tendon

Question 20

what is bledning at the line alba

Answer 20

midline blending of aponeuroses - eg contralateral ext oblique and int oblique will mesh together diagonally

Question 21

where does the midline linea alba run from

Answer 21

xiphoid process to pubic symphysis

Question 22

where is the linea semilunaris found

Answer 22

lateral boundary of rectus abdominus

Question 23

why is teh rectus abdominus split into tendindous intersections

Answer 23

to improve mechanical efficiency

Question 24

what is the significance of the arcuate line

Answer 24

above it the recuts abdominus is surrounded by a posterior and anterior rectus sheath

below it, there is only an anterior rectus sheath

Question 25

why does such a change happen in the positioning of the layers of teh rectus sheath

Answer 25

Due to gravity most of the organs are located in the lower half of abdominal cavity – added protection

Question 26

where abouts is the arcuate line

Answer 26

about a third down of the way from umbilicus to pubic symphysis

Question 27

what is the inferior epigastric artery a branch of

Answer 27

Question 28

what is the superior epigastric artery a branch of

Answer 28

continuation of internal thoracic artery

Question 29

where do teh epigastric artries lie in relation to the rectus abdominus

Answer 29

posterior

Question 30

which arteries are the intercostal and subcostal arteries a continuation of

Answer 30

posterior intercostal arteries

Question 31

do the superior and inferior epigastric arteries connect?

Answer 31

yes they anastomose

Question 32

how should you incise in relation to the direction of muscle fibres

Answer 32

same direction

Question 33

outline the LSCS incision

Answer 33

suprapubic line

pull rectus muscles apart at midline linea alba

Question 34

through what layers must you pass in a LSCS incision

Answer 34

skin and fascia

anterior rectus sheath

rectus muscle

fascia adn peritoneum

uterine wall

amniotic sac

Question 35

what layers must be passed through in a laparotomy

Answer 35

skin a nd fascia

midline linea alba

peritoneum

Question 36

what are teh consequences of the midline linea alba being a relatively bloodless structure, in terms of healing after a laparotomy

Answer 36

healing isnt as good and there is an increased chance of wound complication s

Question 37

what type of hernia can occur through a surgical incision

Answer 37

incisional hernia

Question 38

what artery is at risk of being damaged in a laparoscopy using a lateral port

Answer 38

inferior epigastric artery

Question 39

what are the boundaries of Hesselbach’s triangle

Answer 39

Question 40

what are teh 2 routes for a hysterectomy?

Answer 40

abdominal or vaginal

Question 41

how does the ureter run in relation to the uterine artery

Answer 41

water under the bridge