Anatomy Practical 1 Flashcards
When the pelvis is correctly positioned where is the ASIS in relation to the pubic symphysis? Where is the inguinal ligament>
Vertical line above
Inguinal ligament perpendicular to floor
What are the 3 apertures in the pelvic wall?
Obturator Canal - artery, vein nerve
Greater Sciatic Foramen - Piriformis, Sciatic nerve, pudendal nerve, sup. and inf. gluteal NAV
Lesser Sciatic Foramen - pudendal and tendon of obturator internus
What makes up the anterior wall of the pelvic inlet?
Pubic bones - pubic symphysis
What makes up the lateral wall of the pelvic inlet?
Sacrospinous ligament - covered by coccygeus and obturator internus muscles (lateral rotator of thigh originating from internal aspect of obturator foramen passing to femur greater trochanter)
What makes up the posterior wall of the pelvic inlet?
Sacrum coccyx, piriformis muscles and covering of fascia
What makes up the inferior wall of the pelvic inlet?
Pelvic floor
Which nerves form the sacral plexus?
S1-S4 join lumbosacral L4,5
Lies on anterior surface of piriformis muscle
What are the branches of the pelvic part of the sympathetic trunk?
- gray rami communicantes (join spinal nerves, distributed to periphery)
- fibres to join hypogastric plexus
Where is the superior hypogastric plexus?
Anterior to sacral promontory
What does the superior hypogastric plexus contain?
Sympathetic, sacral PS and visceral afferent fibres
Forms R. and L. hypogastric nerves
Where does the inferior hypogastric plexus lie?
On either side of the rectum
Formed by hypogastric nerve from superior plexus and pelvic splanchnic nerves
Where does lymph from sigmoidal colon travel?
Inferior mesenteric nodes along IMA
What is the nerve supply of the sigmoid?
Autonomic from hypogastric plexus
What is the blood supply to the sigmoid?
IMA
What is a volvulus?
Sigmoid colon rotate around its mesentery
- may correct spontaneously or rotation may continue until blood supply to sigmoid completely shut off
Where does the rectum begin?
- anterior to S3
- inferiorly passes ending at tip of coccyx pierces pelvic floor and continuous with anal canal
- lower rectum dilated = rectal ampulla
Which parts of the rectum does the peritoneum cover?
Anterior and lateral surfaces of first 1/3
Anterior surface of middle 1/3
Lower devoid
What produces the anorectal angle?
Puborectalis portion of levator ani muscle forms sling at junction of rectum with anal canal pulling this part of bowel forward
What is the blood supply to the rectum?
Superior middle and inferior rectal arteries
What forms the superior rectal artery?
IMA
What forms the middle rectal artery?
IIA (internal iliac artery)
What forms the inferior rectal artery?
Pudendal artery
Anastomoses with middle rectal artery at anorectal junction
Where does the superior rectal vein drain?
Hepatic portal vein
Where do the middle and inferior rectal veins drain?
Caval system - internal iliac
What is the porto-systemic shunt in the rectum?
Superior rectal vein into hepatic portal vein and middle and inf. rectal veins into internal iliac
Where does the common iliac artery divide into the external and internal iliac arteries?
At the pelvic brim
anterior to the sacroiliac joint
What is the course of the internal iliac artery?
Passes down into pelvis to GSF where it divides into anterior and posterior divisions
What are the branches of the internal iliac’s anterior division?
Umbilical (to vas deferens, superior vesicle artery) Obturator Inferior Vesicle Middle rectal Inferior gluteal Uterine (female) Vaginal (female)
What are the branches of the internal iliac’s posterior division?
Iliolumbar
Lateral sacral
Superior gluteal
What is involuntary loss of urine after intra-abdominal pressure increased associated with?
Weakening of:
- medial and lateral pubovesical ligaments
- pubovesical fascia at urterovesical junction
- levator ani
- functional integrity of urethral sphincter
What does the pubocervical ligament attach?
Cervix to anterior pelvic wall
What does the transverse and cardinal ligaments attach?
Cervix to lateral pelvic wall
What does the uterosacral ligament attach?
Cervix to uterosacral ligament
What does uterine prolapse occur as a lack of support of?
Transverse cervical/cardinal ligament
Uterosacral ligament
Levator Ani
Where is the vesico-uterine pouch?
Anteriorly between bladder and uterus
Where is the recto-uterine pouch?
Also called pouch of douglas
- posteriorly between uterus and rectum
- lower point in the female pelvis
Where does the bladder expand as it fills?
Superiorly
What is the shape of an empty bladder?
3 sided pyramid - apex, base, superior surface and 2 inferolateral surfaces
Where is the apex of the bladder?
Directed towards pubic symphysis
Continues superiorly up anterior abdominal wall to umbilicus
Where is the base of the bladder?
- inverted triangle
- faces posteroinferiorly
- 2 ureters enters bladder at 2 corners of base
- urethra drains inferiorly from lower corner
- smooth mucosal lining firmly attached to underlying SM of wall but everywhere else mucosa loosely attached and folded
- trigone
What is the trigone?
Smooth triangular area between openings of ureters and urethra on inside of bladder
Where is the inferolateral surface?
Between levator ani muscles of pelvic floor and adjacent obturator internus
Where is the neck of the bladder?
- surrounds urethra origin
- most inferior part of bladder
- fixed
- anchored by fibromuscular bands (pubovesicular ligaments in women)
Where is the bladder at birth?
Abdominal
Descends with age until after puberty where assumes adult position
What are the major components of the reproductive tract?
Ovaries
Uterus
Vagina
Clitoris
What is the normal position of the cervix?
Angles forward on the vagina
- forms fornix as bulges into vagina
Where do the ovaries develop?
High on posterior abdominal wall like the testes
- descend before birth bringing vessels, lymphatics and nerves
- stop on lateral wall of pelvic cavity unlike the testes
What is the function of the ovaries?
oogenesis
Where do ovulated mature eggs travel?
Into peritoneal cavity -> uterine tube openings (infundibulum with fimbriae) -> ampulla -> ishmus -> joins uterus body
What is the function of the infundibulum?
Facilitates collection ovulated eggs from ovary
What is the function of the ampulla?
Fertilisation
What is the broad ligament?
Peritoneal fold suspending uterus and uterine tubes
What is the ovarian ligament?
Holds ovaries close to uterus
What is the round ligament?
Reflects uterus keeping it anteverted and anteflexed as it passes through inguinal canal to labia majora
What is the landmark for administrating a pudendal nerve block?
Ischial spine
What supplies blood to the uterus?
internal iliac -> uterine artery
What does the uterine artery supply blood to?
Uterus
Vaginal via vaginal artery
What supplies blood to the ovaries?
Abdominal aorta -> ovarian artery
Enlarges in pregnancy to augment uterine blood supply
What does the ovarian artery anastomose with?
Uterine artery
Travel in suspensory ligament of ovary as cross pelvic inlet
What makes up the clitoris?
2 coprora cavernosa
Glans clitoris embedded in CT perineum
What is the bulb of vestibule?
Attached to glans clitoris by thin bands of erectile tissue
What are the Bartholin’s Glands?
Lie on either side of vagina opening underneath bulb of vestibule
- produce secretion during sexual arousal
What is the male equivalent of Bartholin’s Glands?
Bulbourethral glands in men
What is the lymph drainage of the pelvis?
- lymph nodes along internal iliac artery and branches -> into nodes associated with common iliac arteries -> lateral aortic and lumbar nodes (lateral abdominal aorta) -> lumbar trunks -> thoracic duct at T12
What is the lymph drainage of the ovaries and uterine tubes?
Via vessels accompanying ovarian arteries -> lateral aortic and lumbar nodes
What is the perineum?
Area between anus and scrotum/vulva
What is the anterior boundary of the perineum?
Pubic symphysis
What is the superior border of the perineum?
Pelvic floor/diaphragm
Perineal membrane
Deep perineal pouch
What is the lateral border of the perineum?
Ischial tuberosity
What is the posterior border of the perineum?
Tip of coccyx
What is the perineum divided into?
2 triangles
- anterior: urogenital triangle
- posterior: anal triangle
What does the urogenital triangle contain?
Urinary and reproductive system
What does the anal triangle contain?
Anus and external sphincter
What is the major nerve and blood supply to the perineum?
Pudendal
What is the difference in the planes of the 2 triangles of the pelvic floor?
Urogenital triangle is quite horizontal whilst anal triangle is more vertical
What does the deep perineal pouch contain?
Proximal urethra
SM mass/deep transverse perineal muscle in men
Dorsal neurovasculature of clitoris
Where is the superficial perineal pouch?
Between perineal membrane and membranous layer of superficial fascia
Contains erectile tissue of clitoris and skeletal muscles
What does the superficial pouch contain?
- Clitoris and associated muscle (ischiocavernosis)
- bulb of vestibule and bulbospongiosis
- greater vestibular glands
- deep perineal branch of internal pudendal vessels and nerve
- superficial transverse perineal muscle
What is the perineal body?
Posterior border of the urogenital triangle and peroneal membrane
- CT structure
- Muscles of pelvic floor and perineum attach
- deep transverse perineal muscles intersect here
Where does the deep perineal pouch lie?
Between levator ani and perineal membrane
Where does the superficial perineal pouch lie?
Superficial to deep perineal pouch
What is the crus?
Forms the corpus cavernosa in males and clitoris in females (erectile tissue)
How does clitoral erection occur?
Stimulation of PS fibres carried by splanchnic nerves from anterior rami cause arteries in corpora cavernosa to relax = blood filling
What position must patients be in when examining the female pelvis?
Lithotomy Position
Supine - hips and knees flexed to 90 degrees, feet together and knees fall laterally
What is done in a female pelvic examination?
- External genitalia examine (vulva): separate labia majora and minora inspecting for anatomical anomalies/discharge/genital warts
- speculum insert into vagina and insert whilst rotating so blades parted allowing good visualisation of cervix, vaginal fornices and external os of uterus
- remove speculum slowly inspecting walls of vagina for prolapse evidence
What is a ‘pap’ smear test used for?
Pre-malignant cervical lesions
- offered to all ladies between 25-64
- HPV causes cervical cancer in almost all cases
How is a bimanual technique carried out?
- examine uterus
- index and middle finger places in posterior fornix of vagina applying gentle pressure on cervix
- Other hand palpate fundus of uterus in suprapubic region
- palpate right and left iliac fossae for ovaries = impalpable unless pathological
What anaesthetic is offered during childbirth?
- regional anaesthesia = patient remains conscious throughout labour
- pudendal and caudal blocks mean patient can still take part in labout
- general anaesthesia reserved for emergencies
What is spinal anaesthesia?
Inserted into CSF at L3/L4
What is pudendal nerve block?
Pudendal nerve (S2-S4) bathed in local anaesthetic agent
What is a caudal epidural block?
Catheter placed in sacral canal enabling administration of agent to S2-S4 spinal nerve roots
What are fibroids?
Most common benign tumours in women
- myometrium and surrounding CT
- asymptomatic but can cause dysmennorhoea/mennorhagia/painful sexual intercourse/urinary frequency and urgency
What are the common locations of fibroids?
1) Submucosal
2) Subserosal
3) Intramural
4) Other - cervical, round ligament, broad ligament
How are fibroids diagnosed?
USS
MRI
Biopsy
How are fibroids treated?
1) Nothing
2) Medical - analgesia, COCP, progesterone intra-uterine devices
3) Radiological - embolization, radio-frequency ablation
4) Surgery - hysterectomy, uterine artery ligation
What structures commonly fall into/through vagina?
Bladder, uterus, rectum, bowel
When is prolapse more likely to occur?
- older as supporting structures weaken post menopause
- delivered large babies
- long pushing phases of labour
- smoking, obesity, CT disorders, upper respiratory disorders, repetitive strain injuries
What are the types of prolapse?
- uterine
- cystocele (bladder into vagina)
- rectocele (rectum into vagina)
- enterocele (small bowel into vagina)
- urethrocele (urethra into vagina)
- vaginal vault (post hysterectomy)
What are symptoms of a rectocele?
Difficulty passing stool
Constipation
Faecal incontinence
What are symptoms of cysto and uretoceles?
Incomplete bladder emptying and stress incontinence
What is stress incontinence?
Loss of small urine volumes during coughing/laughing/straining/exercising
Activities which increase intra-abdominal pressure = pressure transmitted downwards onto bladder
- pelvic floor muscles and external sphincter contract to prevent urine leakage
- physical changes from pregnancy/childbirth/menopause all contribute to weakened pelvic floor muscles = increased risk of urine leakage
Treatment for stress incontinence?
Lifestyle changes - weight loss, pelvic floor exercises
Surgery - restore normal pressure transmission during periods of increased intra-abdominal pressure
