Child Birth Flashcards
The external obliques attach between the lower ribs and what other three structures?
Iliac crests
Pubic tubercle
Linea alba (midline blending of aponeuroses)
What direction do the fibres of the external obliques run in?
Same direction as external intercostals
The internal obliques and transverse abdominis attach between the lower ribs and what three other structures?
Thoracolumbar fascia
Iliac crest
Linea alba
What do the dividing the rectus abdominis into 3 or 4 smaller muscles do?
Improves mechanical efficiency
Where does the linea alba run from?
Xiphoid to pubic symphysis
What is the arcuate line?
Horizontal line
Marks the lower limit of the posterior rectus sheath
Where do the inferior epigastric vessel perforate the rectus abdominis?
At the arcuate line
Half way between umbilicus and pubic crest
What is the anterior rectus sheath composed of?
External oblique aponeurosis
AND
Anterior lamina of internal oblique aponeurosis
What is the posterior rectus sheath composed of?
Posterior lamina of internal oblique aponeurosis
AND
Transverse abdominis aponeurosis
What is the structure of the rectus sheath below the arcuate line?
All 3 layers of aponeuroses make the sheath which runs anterior to the rectus abdominis:
- External oblique aponeurosis
- Internal oblique aponeurosis
- Transverse abdominis aponeurosis
What part(s) of the rectus sheath are cut when undertaking a suprapubic incision (lower segment Cesarean section)?
Anterior sheath only (as it is below arcuate line)
Why is the rectus sheath stitched closed after surgery?
Increased wound strength
Reduced risk of would complications:
- Incisional hernia
From what spinal segment does the iliohypogastric nerve arise?
L1
From what spinal segment does the ilioinguinal nerve arise?
L2
Where plane do the nerves supplying the anteriolateral abdominal wall travel in?
Plane between:
- Internal oblique and
- Transverse abdominis
What part of the abdominal wall do the superior epigastric arteries supply?
Anterior wall
What artery do the superior epigastrics originate from?
Continuation of internal thoracic arteries
Where do the superior epigastric arteries arise from and lie?
Emerge at superior aspect of abdominal wall
Lie posterior to rectus abdominis
What part of the abdominal wall do the inferior epigastric arteries supply?
Anterior
What artery do the inferior epigastric arteries originate from?
Branch of external iliac
Where do the inferior epigastric arteries arise from and lie?
Emerge at inferior aspect of abdominal wall
Lie posterior to rectus abdominis
What part of the abdominal wall do the intercostal and subcostal arteries supply?
Lateral wall
What artery do the intercostal and subcostal arteries originate from?
Continuation of posterior intercostal arteries
Where do the intercostal and subcostal arteries arise from?
Lateral aspect
In a LSCS incision, what happens to the rectus muscles?
NOT cut:
- Separated laterally towards their nerve supply
What layers are cut/separated in an LSCS?
- Skin and fascia
- (Anterior) rectus sheath (inferior to arcuate line)
- Rectus abdominis (separated)
- Fascia and peritoneum
- Bladder retracted
- Uterine wall
- Amniotic sac
What layers of the abdominal wall are stitched closed after an LSCS?
Uterine wall (with visceral peritoneum)
Rectus sheath
Fasica (if high BMI)
Skin
What layers are opened for a laparotomy?
Skin and fascia
Linea alba
Peritoneum
What layers are stitched closed following a laparotomy?
Peritoneum
Linea alba
Skin (fascia if high BMI)
Why does a laparotomy have an increased risk of wound complication?
Bloodless
What wound complications can result after a laparotomy?
Dehiscence
Incisional hernia
When inserting a lateral laparoscopic port, what must be avoided?
Inferior epigastric artery
How can the pelvic organs be viewed during laparoscopy?
Forceps inserted through vagina to grasp cervix and manipulate uterus
Where does the inferior epigastric artery emerge?
Just medial to the deep inguinal ring
Halfway between:
- ASIS
- Pubic tubercle
What direction does the inferior epigastric artery move in?
Superomedial direction posterior to rectus abdominis
Why must care be taken during a hysterectomy in regards to arteries?
Differentiate the ureters and uterine arteries:
- Ureter passes inferior to artery
- Ureters will ‘vermiculate’ when touched
What are the 3 components of the pelvic floor?
Pelvic diaphragm
Muscles of perineal pouches
Perineal membrane
What is the deepest layer of the pelvic floor?
Pelvic diaphragm
What does the pelvic diaphragm consist of?
2 muscle groups:
- Levator ani
- Coccygeus
There is an anterior gap between the medial borders of the pelvic diaphragm, what is this called and what does it allow?
Urogenital hiatus allowing passage of:
- Urethra (M and F)
- Vagina (F)
What are the origins of the levator ani?
Pubic bones
Ischial spines
Tendinous arch of levator ani
What are the insertions of the levator ani?
Perineal body
Coccyx
Walls of organs in the midline
What are the 3 parts of the levator ani?
Puborectalis
Pubococcygeus
Ilicoccygeus
What must the levator ani do to allow urination and defaecation?
Relax
What is the levator ani innervated by?
Pudendal nerve (S3, S4) Nerve to levator ani (S4)
Where does the deep perineal pouch lie?
Below fascia covering the inferior surface of the pelvic diaphragm
Superior to perineal membrane
What does the deep perineal pouch contain?
Part of urethra (and vagina) Bulbourethral glands (male) Neurovascular bundle for penis/clitoris Extensions of the: - Ischioanal fat pads - Muscles
Where does the perineal membrane attach?
Laterally to the sides of the pubic arch (close urogenital triangle)
What are the openings in the perineal membrane for?
Urethra
Vagina
What parts of the penis does the superficial perineal pouch contain in males?
Bulb of penis - Corpus spongiosum Crura of penis - Corpus cavernosa Associated muscles: - Bulbospongiosus - Ischiocavernosus
What else does the superficial perineal pouch contain (apart from parts of the penis) in males?
Proximal spongy (penile) urethra Superficial transverse perineal muscle Branches of: - Internal pudendal vessels - Pudendal nerve
What parts of the female erectile tissue does the superficial pouch contain?
Clitoris and crura - Corpus cavernosa Bulbs of vestibule (paired) Associated muscles: - Bulbospongiosus - Ischiocavernosus
What else does the superficial perineal pouch contain (apart from parts of the female erectile tissue) in females?
Greater vestibular glands Superficial transverse perineal muscles Branches of: - Internal pudendal vessels - Pudendal nerve
What does tonic contraction of the puborectalis do?
Bends anorectum anteriorly:
- Maintains faecal continence
What does active contraction of the puborectalis do?
Maintains continence after rectal filling
What does urinary continence depend on?
Urinary bladder neck support
External urethral sphincter
Smooth muscle in urethral wall
What is a cystocoele?
Bladder moves through prolapse in anterior vaginal wall
What is an enterocoele?
Loops of small bowel move through prolapse in upper posterior vaginal wall
What is a rectocoele?
Rectum moves through prolapse in lower posterior vagina wall
What is a 1st degree uterine prolapse?
Lowest part descends halfway down vagina
What is a 2nd degree uterine prolapse?
Lowest part at vaginal entrance
What is a 3rd degree uterine prolapse?
Lowest part lies outside of vagina
What is a 3rd degree uterine prolapse also known as?
Procidentia
What are the symptoms of a uterine prolapse?
Dragging sensation
Feeling of a ‘lump’
Urinary incontinence
When is a sacrospinous fusion carried out?
To repair a cervical or vault descent
How is a sacrospinous fusion carried out?
Vaginally:
- Sutures placed in sacrospinous ligament
- Just medial to the ischial spin
What does a sacrospinous fusion risk injury to?
Pudendal neurovascular bundle
Sciatic nerve
How is incontinence surgery carried out?
Trans-obturator approach Mesh through obturator canal: - Space in obturator foramen for passage of NVB - Create a sling around urethra - Incisions through vagina and groin
What are the three key factors for labour?
Power (of uterine contractions)
Passage (size of maternal pelvis)
Passenger (size of foetus)
What role does progesterone play in labour?
Promotes smooth muscle relaxation (keeps uterus ‘settled’)
Prevents formation of gap junctions
Reduces contractility of myocytes
What role does oestrogen play in labour?
Makes uterus contract
Promotes prostaglandin production
What role does oxytocin play in labour?
Initiates and sustains contractions
Acts on decidual tissue to promote prostaglandin release
What synthesises oxytocin during labour?
Decidual tissue
Extra-embryonic foetal tissues
Placenta
What happens to the number of oxytocin receptors near the pregnancy? In what tissues?
Increases in:
- Myometrium
- Decidual tissues
What does myometrial stretch do in the initiation of labour?
Increases excitability of myometrial fibres
What is the Ferguson reflex?
- Increased pressure on cervix
- Oxytocin release
- Contractions
- Positive feedback to step 1.
What does the secretion of pulmonary surfactant into the amniotic fluid do?
Prostaglandin synthesis
What does a rise in foetal cortisol?
Increases maternal oestriol
What does an increase in myometrial oxytocin receptors and their activation do?
Phospholipase C activity:
- Increased cytosolic calcium
- Increased uterine contractility
What is the latent phase of the first stage of labour?
Up to 3-4cm cervical dilatation
What is the active phase of the first stage of labour?
4-10cm (full) cervical dilatation
What is the second stage of labour?
From full dilatation to delivery of the baby
What is the third stage of labour?
From delivery of baby to the expulsion of placenta and membranes
What happens during the latent phase of the first stage of labour?
Mild irregular uterine contractions
Cervix shortens and softens
How long does the latent phase of the first stage of labour last?
Variably duration:
- May last a few days
What happens during the active phase of the first stage of labour?
4-10cm cervical dilatation Slow descent of the presenting part Contractions progressively become more: - Rhythmic - Strong
In nulliparous women, when is the second stage of labour deemed prolonged?
If it lasts longer than:
- 3 hours if there is regional anaesthesia
- 2 hours without regional anaesthesia
In multiiparous women, when is the second stage of labour deemed prolonged?
If it lasts longer than:
- 2 hours if there is regional anaesthesia
- 1 hour without regional anaesthesia
How often is vaginal examination done to assess cervical dilatation in low risk care?
Infrequently
How long does the third stage of labour last for?
10 minutes (Can last from 3 minutes longer)
What is the expectant management of the third stage of labour?
Spontaneous delivery of placenta
What is the active management of the third stage of labour?
Use of oxytocic drugs
Controlled cord traction
What does the active management of the third stage of labour reduce the risk of?
Post-Partum haemorrhage
What drugs can be used during the active management of the third stage of labour?
Administration of Syntometrine - 1ml ampoule containing: - 500mcg ergometrine maleate AND - 5 IU oxytocin OR Administration of 10 IU oxytocin
How else can active management of the third stage of labour be carried out?
Cord clamping and cutting
Controlled cord traction
Bladder emptying
What effect does hyaluronic acid have on the cervix?
Increases molecules between collagen fibres:
- Results in cervical softening
What effect does reduced collagen fibre bridging have on the cervix?
Reduces cervical firmness:
- Results in cervical softening
What causes cervical ripening?
Reduced collagen fibre alignment Reduced collagen fibre strength Reduced tensile strength of the cervical matrix Increased cervical decorin: - Dermatan sulfate proteoglycan 2
What are Braxton Hicks Contractions?
Tightening of the uterine muscles:
- Thought to aid the body prepare for labour
How early can Braxton Hicks Contractions start?
6 weeks
When are Braxton Hicks Contractions usually felt?
2nd or 3rd trimester
What effect can Braxton Hicks Contractions have on the cervix?
Thin it
How can Braxton Hicks Contractions be differentiated from uterine contractions in labour?
Irregular
Frequency and duration stay constant:
- Do not increase
Relatively painless
How can Braxton Hicks Contractions be resolved?
Ambulation
Change in activity
What is the spacing of true labour contractions?
Evenly spread:
- Typically starts at about 5 minutes apart
- Time between them shortens
How do true labour contractions change as they progress?
Get more intense
Get more painful
Last longer
What is the purpose of true labour contractions?
Tighten the top of the uterus:
- Pushes baby down into birth canal
How does the abdomen feel during true labour contractions?
Rigid
What cervical changes occur during true labour contractions?
Softening
Effacement
Dilatation
How does position affect true labour contractions?
Do not resolve
What kind of muscle is in the uterus?
Smooth
Where is uterine muscle most dense?
At fundus
What is cervical tissue made up of?
Collagen (mainly), types: - 1 - 2 - 3 - 4 Smooth muscle Elastin
What are the components of cervical tissue held together by?
Connective tissue ground substance
Where is the pacemaker for uterine contractions? What does it do?
Region of the tubal ostia:
- Wave spreads downwards
- Synchronisation of contraction waves from both ostia
What happens to the upper segment of the uterus during contractions?
Contracts
Retracts
What happens to the lower segment of the uterus (and the cervix) during contractions?
Stretch
Dilate
Relax
Where is the dominance of the uterine contractions?
Fundus
What is the intensity of a uterine contraction essentially?
Degree of uterine systole
When is the intensity of uterine contractions greatest?
2nd stage of labour
What is the typical frequency of uterine contractions?
Up to 3-4 in 10 minutes
How long does a uterine contraction last initially and what is the max length?
Initially 10-15 seconds
Max 45 seconds
What is the typical gynaecoid AP diameter of the pelvic outlet?
12-13cm
What is the typical gynaecoid transverse diameter of the pelvic inlet?
13.5-14cm
What is the typical gynaecoid transverse diameter of the pelvic outlet?
11cm (between ischial tuberosities)
What is the typical gynaecoid oblique diameter of the pelvic outlet?
12cm
What is the oblique diameter of the pelvis?
Sacroiliac joint to contralateral iliopubic eminence
What is the shape of the anthropoid pelvis?
Oval shaped inlet
AP > Transverse diameter
What is the shape of an android pelvis?
A typically ‘male’ pelvis
Heart shaped/Triangular inlet
What results in the shape of an android pelvis?
Prominent sacrum
Who is an android pelvis most common in?
Afro-Caribbean women
What is the normal foetal position?
Longitudinal lie Cephalic presentation Position: - Occipitoanterior - Head engages occipitotransverse Flexed head
What are abnormal foetal positions?
Presentation: - Breech - Oblique lie - Transverse lie Position: - Occipitoposterior
What is the sequence of movements of the foetus during labour?
- Engagement and descent of the head in an occipitotransverse position as it descends through pelvic inlet
- Neck flexion
- Internal rotation of neck to OA position
- Crowing and extension of neck
- Restitution and external rotation (head back to OT to aid shoulder delivery)
- Expulsion
How is the anterior shoulder delivered?
Downward traction:
- Lateral flexion posteriorly
How is the posterior shoulder delivered?
Upward traction:
- Lateral flexion anteriorly
How is the descent of the foetal head measured?
In abdominal fifths
What parts of the foetal head are used to determine the position of the foetal head?
Frontal synciput
Occipital eminences
When are vaginal exams for cervical assessment carried out during normal labour?
~4 hourly
What is crowning?
Appearance of a large segment of foetal head at the introitus
Labia stretched to full capacity
Largest head diameter encircled by vulval ring
What does the Bishop Score aid in the assessment of?
Cervix
Helps determine if labour will be:
- Spontaneous
- Induced
What are the dilatation scores in the Bishop Score?
0cm = 0 points 1-2cm = 1 point 3-4cm = 2 points >5cm = 3 points
What are the effacement scores in the Bishop Score?
0-30% = 0 points 40-50% = 1 point 60-70% = 2 points 80-100% = 3 points
What are the station scores in the Bishop Score?
-3 = 0 points
-2 = 1 points
-1 = 2 points
+1 or +2 = 3 points
What are the cervical consistency scores in the Bishop Score?
Firm = 0 points Med. = 1 point Soft = 2 points
What are the cervix position scores in the Bishop Score?
Posterior = 0 points Mid. = 1 point Anterior = 2 points
What Bishop’s Score indicates labour is likely to be spontaneous/induction would likely work?
> =9 points
What Bishop’s Score indicates labour is likely to proceed and induction will likely not work?
=<5 points
What amount of blood loss is normal during labour?
<500 ml
What amount of blood loss is abnormal and more significant?
> 1500 ml
Where is the plane of separation for the placenta?
Spongy layer of decidua basalis
What causes placental separation?
Shearing force
What are the methods of placental separation?
Matthew Duncan: - Marginal - Most common Schultz: - Central
What 3 signs indicate placental separation in the 3rd stage of labour?
Uterus hardens, contracts and rises
Umbilical cord lengthens permanently
Gush of blood cariable
When is the 3rd stage of labour considered normal up to?
30 minutes
How is haemostasis after labour achieved?
Tonic contraction:
- Lattice pattern of uterine muscles strangulates blood vessels
Thrombosis of torn vessel ends:
- Hypercoagulability in pregnancy
Myo-tamponade due to opposition of AP walls
How long does it take the tissues to return to a non-pregnant state after labout?
Over 6 weeks