Repro Session 5 Flashcards
What are the bony landmarks that are palpable O/E of the pelvis?
Iliac crest, linea terminalis, ischial spine and ischial tuberosity
What is the promontory?
Anterior superior edge of the 1st sacral vertebra
What is the false pelvis?
Above linea terminalis where a foetus of any size can be accommodated
What is the true pelvis?
Bony canal below linea terminalis that is solid and immobile
What allows a small amount of laxity in the true pelvis during pregnancy?
Hormones acting on the pubic symphysis
What are the two ligaments of the pelvis?
Sacrospinous and sacrotuberous
What is the pelvic inlet?
Boundary between the greater and lesser pelvis determining the size and shape of the birth canal
What are the alternative names of the pelvic inlet?
Linea terminalis and iliopectineal line
Where is the plane of greatest diameter in the pelvis?
From mid pubic symphysis to IV disc of S2/3
Where is the plane of least diameter found in the pelvis?
Inferior pubic symphysis to between S5 and coccyx (obstetric conjugate)
Where is the pelvic outlet found?
At the end of the lesser pelvis at the beginning of the pelvic wall
How is the pelvic outlet increased in pregnancy?
Hormones increase laxity of sacrotuberous and allow movement of the coccyx
What is assessed in the midpelvis on clinical examination?
Straight side walls and bispinous diameter (between ischial spines)
What is assessed at the pelvic outlet on clinical assessment of the pelvis?
Infrapubic angle and distance between ischial tuberosities
What is the obstetric conjugate?
Sacral promontory to midpoint of pubic symphysis
What is the diagonal conjugate?
Sacral promontory to inferior pubic symphysis
Which conjugate is used clinically to assess AP diameter of the pelvis and why?
Diagonal as the inferior pubic symphysis can be palpated
What are the differences between a gynecoid and android pelvis?
Gynecoid has wider ilium, flared alar, larger and more circular pelvic inlet, small ischial spines, straight side walls, larger sub-pubic angle, well curved sacrum and larger sciatic notch
What makes up the lateral border of the pelvic inlet?
Iliopectineal line
What forms the anterior border of the pelvic inlet?
Public symphysis
What forms the posterior border of the pelvic inlet?
Sacral promontory
What forms the anterior border of the pelvic outlet?
Pubic arch (inferior border of ischiopubic rami)
What forms the lateral border of the pelvic outlet?
.
Ischial tuberosity and sacrotuberous ligament
What forms the posterior border of the pelvic outlet?
Tip of coccyx
What are the 4 bones that form the pelvis?
2 inominate bones, sacrum and coccyx
What are the components of the broad ligament of the uterus?
Mesosalpinx, mesovarium and mesometrium
What are the components of the uterine tube?
Infundibulum, ampulla, isthmus and uterine part
Where do the ovaries develop?
Within the mesonephric ridge
What is the function of the mesovarium?
Attach ovary to posterior surface of broad ligament of the uterus
What type of mesothelium is found in the ovaries before puberty?
Simple cuboidal
What happens to the ovarian mesothelium with each ovulation?
Becomes scarred
What contains the ovarian vessels, lymph and nerves?
Suspensory ligament of the ovary
What is the ligament of ovary, found in the mesovarium, a remnant of?
Gubernaculum
What tethers the ovary to the uterus?
Ligament of ovary
What does the ligament of ovary continue as after attaching to the ovary?
Round ligament of uterus
Where are the ovaries typically found?
Laterally between uterus and lateral pelvic wall
What provides arterial supply to the ovaries?
Ovarian arteries, direct branches of AA
Where does the venous drainage of the ovaries empty?
L ovarian vein to L renal vein, R ovarian vein to IVC
Where does lymph from the ovaries drain?
Paraaortic nodes
What gives innervation to the ovaries?
Sympathetic from ovarian plexus, parasympathetic from uterine plexus
Approximately how long are the uterine tubes?
10 cm
Describe the position of the uterine tubes.
Lie in the mesosalpinx to form the free anterosuperior edge of broad ligament. Extend posterolaterally to lateral pelvic walls then arch anterior and superior to ovaries
Are the uterine tubes always symmetrical?
No, often asymmetrical
Describe the infundibulum of the uterine tubes.
One large ovarian fimbria attaches to the superior pole of the ovary and the rest spread over the medial surface
Which part of the uterine tube is the widest and longest and therefore best for fertilisation?
Ampulla
What is the connection of the uterine tube to the uterine horn called?
Isthmus
Describe the uterine part of the uterine tube.
Short intra-mural segment opening via the uterine ostium into the uterine cavity
Why is implantation in the uterine tube potentially catastrophic?
Lining is specialised for conduction and has a rich blood supply so gives huge risk of haemorrhage
What gives arterial supply to the uterine tubes?
Uterine and ovarian arteries
What gives venous drainage to the uterine tubes?
Uterine and ovarian veins
Where does lymph from the uterine tubes drain?
Iliac, sacral and aortic nodes
What gives innervation to the uterine tubes?
Ovarian and uterine plexuses and sensory afferents from T11-L1
What happens in ectopic tubal pregnancy?
Pyosalpinx causes formation of an adhesion so the blastocyst cannot pass to the uterus
What happens to oocytes following ligation of the uterine tubes?
Degenerate and are absorbed
What can develop in the Gartner (Wolffian) duct if it does not degenerate fully?
Cyst
How is bimanual examination of the uterus performed?
2 gloved fingers of R hand inserted into vagina whilst L hand is pressed inferoposteriorly on public region of anterior abdominal wall
What is Hegar sign?
Softening of isthmus indicates pregnancy (feels like cervix is away from body of uterus)
What is the clinical relevance of the recto uterine pouch?
Can drain pelvic abscess or aspirate accumulated peritoneal cavity fluid by culdocentesis
What does the exact position of the uterus depend on?
Distension of the bladder
What is the usual position of the uterus?
Anteverted w.r.t. vagina, anteflexed w.r.t.cervix so immediately posterosuperior to bladder and anterior to rectum
Which uterine positions increase the risk of uterine prolapse?
Anteflexed and retroverted. Retroflexed and retroverted
What are the components of the uterus?
Fundus, body and cervix
Where is the usual site of implantation of the blastocyst?
Body of uterus
What does the uterus develop as a result of?
Persistence of paramesonephric ducts due to absence of MIH
What happens to form the mesentery of the uterus, uterine tube and ovary?
Fusion of the uterus in the midline creates a broad transversus fold draped by peritoneum
How is the uterus supported in the pelvic cavity?
Dynamically by pelvic diaphragm and passive by its position
What happens to the uterus when intra-abdominal pressure increases?
It presses in the bladder
What are the anterior relations of the uterus?
Uterovesicle pouch and superior surface of bladder
What are the posterior relations of the uterus?
Rectouterine pouch containing loops of small intestine and anterior rectal surface
What is the lateral relation of the uterus?
Peritoneal broad ligament
Why can contiguous spread of cervical cancer to the bladder arise?
Close anterior relation of uterus and bladder
What gives arterial supply to the uterus?
Uterine people artery from anterior internal iliac
What gives venous drainage to the uterus?
Plexus in broad ligament that empties into the uterine and then internal iliac veins
Describe the lymphatic drainage of the uterus.
Fundus: aortic and inguinal nodes. Body: external iliac nodes. Cervix: external and internal iliac nodes and sacral nodes
What gives innervation to the uterus?
Uterovaginal plexus
What is the internal os?
Junction between uterine cavity and endocervical canal
What epithelium lines the endocervical canal?
Mucus-secreting simple columnar
What is the external os?
Junction between the endocervical canal and ectocervix
What epithelium lines the ectocervix?
Stratified squamous non-keratinised
What forms the cardinal and utero sacral ligaments of the cervix?
Condensations of endopelvic fascia
Where is the cardinal ligament of the uterus found?
Base of broad ligament extending from cervix to lateral pelvic walls
What does the cardinal ligament of the cervix contain?
Uterine artery and vein
What is the function of the cardinal ligament of the cervix?
Lateral stability
What is the function of the uterosacral ligament of the cervix?
Maintain anteversion
Where does the uterosacral ligament extend from and to?
From cervix to sacrum
What gives arterial supply to the cervix?
Uterine artery
What gives venous drainage to the cervix?
Uterine veins via uterine plexus
What is the vagina?
Distensible musculomembranous tube 7-9 cm long from the middle cervix to the vaginal orifice
Is the vagina usually collapsed or open?
Collapsed so lateral walls are in contact
What is the vaginal fornix?
Recess around fornix with anterior, posterior and lateral parts
Which part of the vaginal fornix is deepest and is related to the rectouterine pouch?
Posterior
What is the glans of clitoris formed from?
Corpora cavernosa
What does the vestibule of the vagina contain to secrete mucus?
Ducts of vestibular/Bartholin glands
What are the Bartholin glands homologous to in the male?
Bulbourethral glands except these are in deep perineal pouch (Bartholin in superficial)
What can be used as a landmark for anaesthesia of the pudendal, inferior cluneal, obturator, genitofemoral and ilioinguinal nerves?
Ischial spine
What types of fistula can obstetric trauma lead to?
Vesicovaginal, urethrovaginal or rectovaginal
What are the anterior relations of the vagina?
Fundus of urinary bladder and urethra
What are the lateral relations of the vagina?
Levator ani, visceral pelvic fascia and ureters
What are the posterior relations of the vagina from inferior to superior?
Anal canal, rectum and rectouterine pouch
What are the 4 muscles that compress the vagina, acting as sphincters?
Pubovaginalis, EUS, urethrovaginal sphincter and bulbospongiosus
What gives arterial supply to the vagina?
Uterine and vaginal arteries (internal iliac)
What gives venous drainage to the vagina?
Vaginal venous plexus draining to uterine vein and internal iliac veins
Where does lymph from the vagina drain?
Iliac and superficial inguinal nodes
What gives innervation to the superior 4/5 of the vagina?
Uterovaginal plexus
What gives somatic innervation to the inferior 1/5 of the vagina?
Deep perineal nerve from pudendal
What gives arterial supply to the vulva?
Parked pudendal arteries (internal branch mainly)
What gives venous drainage to the vulva?
Pudendal veins and smaller labial veins
What happens in sexual activity to increase the size of the clitoris?
Veins of vulva engorge
Where does lymph from the vulva drain to?
Superficial inguinal nodes
What gives sensory innervation to the vulva?
Anterior from ilioinguinal nerve and genital branch of genitofemoral. Posterior from pudendal and posterior cutaneous nerve of thigh
What gives parasympathetic innervation to the clitoris and vestibule?
Cavernous nerves from uterovaginal plexus
Describe the structure of innervation above the pelvic pain line.
Visceral afferents from intraperitoneal uterine fundus and body follow sympathetic innervation to inferior thoracic and superior lumbar thoracic ganglia
Describe the organisation of innervation below the pelvic pain line.
Afferent fibres from subperitoneal uterine cervix and vagina follow parasympathetic fibres through plexuses to S2-4 spinal ganglia
What are the pros and cons of general anaesthesia for childbirth?
A: emergencies and mothers preference. D: needs maternal respiratory and maternal and foetal cardiac function monitoring
What allows childbirth under general anaesthetic to be passive?
Hormones and obstetrician
Where is spinal anaesthetic for childbirth administered?
Subarachnoid space of L3-L4
What sensation is lost in spinal anaesthesia for childbirth?
Perineum, pelvic floor, birth canal, lower limbs and uterine contractions
Why is electrical monitoring of uterine contractions needed in spinal anaesthesia for childbirth?
They cannot be felt by the mother
What sensation is lost in pudendal anaesthesia for childbirth?
S2-4 dermatomes and inferior 1/4 of vagina
What is the advantage of using pudendal anaesthesia for childbirth?
Uterine contractions are maintained
How is a caudal epidural given in childbirth?
In-dwelling catheter placed in sacral canal between S2-4 in advance
How is laparoscopic examination of the pelvic viscera performed?
Laparoscope into peritoneal cavity below umbilicus, insufflation of inert gas, elevate pelvis so gravity pulls intestines into abdomen and external manipulation of uterus as necessary
What can laparoscopic examination be used for in the female reproductive tract?
Ovarian cysts, tumours, endometriosis and ectopic pregnancies
What is the pelvic floor?
Muscular and fibrous tissue diaphragm that fills the lower pelvic canal, closes the abdominal cavity, defines the upper border of the perineum and supports the pelvic organs
What is the function of the pelvic floor?
Continence, rotation of baby in childbirth, truncal stability (with abdominal muscles)
What forms the lateral wall of the pelvic cavity?
R and L hip bones, obturator membrane and obturator internus
What forms the antero-inferior pelvic wall?
Pubic bodies, rami and symphysis
What forms the floor of the pelvic cavity?
Muscle and fascia of coccygeus and levator ani
What forms the posterolateral wall of the pelvic cavity?
Sacrum, coccyx, anterior sacroiliac, sacrospinous and sacrotuberous ligaments
What are the two holes in the pelvic floor for?
Anterior urogenital hiatus for urethra and vagina. Central rectal hiatus for anal canal
Describe the arterial supply to all pelvic organs.
Internal iliac artery –> posterior trunk –> pudendal, vaginal and inferior rectal arteries
Why is puborectalis a major component of anal continence?
Sling action gives 80 degree anorectal flexure
What happens if the pudendal nerve is stretched during childbirth?
Neurapraxia-transient innervation loss and weakness of muscles causing anorectal incontinence
What gives innervation to levator ani?
Pudendal nerve
What are the spinal roots of the pudendal nerve?
S2-4
What are the anatomical borders of the perineum?
Anterior: pubic symphysis. Posterior: tip of coccyx. Lateral: inferior public rami, inferior ischial rami and sacrotuberous ligament. Roof: pelvic floor. Base: skin and fascia
What are the surface borders of the perineum?
Anterior: mons pubis/penis base. Lateral: medial surface of thighs. Posterior: superior end of intergluteal cleft
What are the contents of the urogenital triangle form deep to superficial?
Deep perineal pouch, perineal membrane, superficial perineal pouch, deep perineal fascia, superficial perineal fascia and skin
What is the deep perineal pouch?
Potential space between pelvic floor and perineal membrane
What are the contents on the deep perineal pouch?
Urethra, EUS, bulbourethral glands and deep transverse perineal muscles
Which muscles does the perineal membrane provide attachment for?
Superficial external genitalia muscles
What is the perineal membrane perforated by?
Urethra and vagina
What is the superficial perineal pouch?
Potential space between perineal membrane and fascia
What are the contents of the superficial perineal pouch?
Erectile tissue, ischiocavernosus, bulbospongiosus, superficial transverse perineal muscles and bartholins glands
What is the seep perineal fascia?
Fascia covering the superficial perineal muscles
What is the superficial perineal fascia continuous with?
Fascia of abdominal wall
What forms the labia majora and mons pubis?
Superficial fatty layer of superficial perineal fascia
What is found in the anal triangle?
Anal aperture, external anal sphincter and 2 ischioanal fossae
Where are the 2 ischioanal fossae located in the anal triangle?
Lateral to anus, continuous with ischioanal fat
What are the pros and cons of a midline tear/episiotomy in childbirth?
Easier to repair due to fewer structures involved but endangers the anal sphincter
What are the pros and cons of a mediolateral tear/episiotomy during childbirth?
Anal sphincter is protected but is harder to repair as more structures involved
What is the perineal body?
Irregular fibromuscular mass in the centre of the perineum between the anterior and posterior triangles
Which muscles attach to the perineal body?
Levator ani, bulbospongiosus, superficial and deep transverse perineal muscles, external anal sphincter muscles and EUS fibres
Why is the endopelvic fascia divided into 3 levels of support in uterine prolapse?
Each gives a different level of support that needs to be identified so that treatment an be most effective
What forms level 1 of endopelvic fascial support?
Uterosacral and cardinal ligament complex
What forms level 2 of endopelvic fascia support?
Arcus tendinosus, fascia pelvis and rectovaginalis
What forms level 3 of endopelvic fascia support?
Perineal body
How can prolapse and incontinence arise from pelvic floor damage?
Stretch and damage to pelvic floor muscles and supporting ligaments causes muscle weakness and ineffective muscle action
What are risk factors for developing prolapse of incontinence following pelvic floor damage?
Age, obesity, menopause due to low oestrogen, chronic cough and smoking causing CT laxity
What is the treatment plan for prolapse due to pelvic floor damage?
Remove prolapsed organs, restore CT supports and maintain function
What are possible S/E associated with prolapse treatment?
Recurrence, new incontinence or dyspareunia
What proportion of females >40 y.o. are affected by in continence?
50%
How do pelvic floor exercises treat incontinence due to pelvic floor damage?
Rapid and long contractions of slow and fast twitch fibres cures 50-75% of pts and prevents progression
How does surgery treat incontinence due to pelvic floor damage?
Increases support to sphincter mechanism and bladder neck by colposuspension or tension free vaginal tape
What are the possible S/E associated with surgical treatment of incontinence following pelvic floor damage?
Voiding difficulty, retention, overactive bladder due to partial obstruction
