Pelvis Flashcards
What does the pelvis consist of
To hip bones which articulate with the sacred posteriorly at the sacroiliac joints and anteriorly with the pubic symphysis
What is another name for the hip bones
Innominate bones
Where does the bladder lie
What is it covered by
Posterior to the pubic
It is covered superiorly by peritoneum
What is the arterial supply and the bladder and what is its Venous drainage
Supplied by the superior and inferior vesical arteries from the internal iliac artery
Veins drain to the Venus plexus at its base and around the prostate gland
What is the detrusor muscle of the bladder supplied by
Parasympathetic fibres
Why do additional sympathetic fibres go to the male’s bladder neck
To close the bladder neck during ejaculation
What is the uterus comprised of
A fundus, body, and cervix
What is the usual position of the uterus
Anteflexed and anteverted
What are the pouches that lie anterior and posterior to the uterus
The vesicouterine Pouch and the rectouterine Pouch
What does each testis comprise
An anterior part, the body, and the posterior part, the epididymis
What is continuous with the tail of the epididymis
Vas deferens
What does the spermatic cord contain
The vas deferens, testicular artery, veins and lymphatics, the obliterated processus vaginalis, sympathetic nerves, and arteries to the vas deferens and cremaster
Where does the rectum commence
When does it become the anal canal
S3
At the level of the pelvic floor
The pelvic peritoneum encloses the sigmoid colon completely, what does this form
The sigmoid mesocolon (a mesentery)
What does the visceral peritoneum do in females
The visceroperitoneum on the posterior surface of the uterus continues down onto the posterior surface of the vagina and turned backwards onto the anterior surface of the rectum forming the rectouterine pouch
The patch between the uterus and the bladder is called what
The vesicouterine pouch
How does the rectovesical pouch form in males
The peritoneum is reflected from the rectum onto the base and upper part of the bladder
What may collect in the peritoneal pouches and why
Inflammatory exudate
Because the pouches are the most inferior point of the peritoneal cavity
Describe the course of the internal iliac artery
It arises from the bifurcation of the common iliac artery, anterior to the secret iliac joint, and descends on the posterior pelvic wall to the greater sciatic notch.
It then divides into anterior and posterior trunks, which give both parietal and visceral branches.
What does the internal iliac artery continue as in the fetus
The umbilical artery
Describe the umbilical artery in the fetus
It ascends up the abdominal wall to the umbilicus to reach the placenta via the umbilical cord
What happens to the umbilical artery at birth
It is obliterated to form a fibrous cord which is visible as the medial umbilical ligament
Name some of the visceral branches of the internal iliac artery
Superior and inferior vesical arteries, the middle rectal artery and the uterine artery
Name some of the parietal branches of the internal iliac artery
The obturator artery, the internal pudendal artery, and the superior and inferior gluteal arteries.
Where does the superior hypogastric plexus lie
What is it a continuation of
On the sacral promontory between the common iliac arteries
The aortic plexus, with branches from the third and fourth number sympathetic ganglion
Is the superior hypogastric plexus solely sympathetic
No it also contains parasympathetic fibres which are send from the inferior hypogastric plexuses
The superior hypogastric plexus gives branches to which other plexuses
The ureteric, gonadal, and common iliac practices
It also divides into the inferior hypogastric plexus
Give a brief overview of the inferior hypogastric plexus
In fact there are two: the right and left hypogastric practices which lie either side of the rectum
What kind of fibre do each of the right and left inferior hypogastric plexuses contain
Each plexus contains sympathetic fibres (Mainly postganglionic) from the superior hypo gastric plexus and sacral sympathetic ganglion, together with parasympathetic (preganglionic) fibres from the pelvic splanchnic nerves
What do the extensions from the left and right inferior hypogastric plexuses allow
Autonomic fibres to be distributed to the pelvic viscera, these are collectively known as the pelvic plexuses
Name the pelvic plexuses
Rectal, vesical, uterovaginal, prostatic
True or false urinary bladder is extraperitoneal
True
Which part of the urinary bladder is adherent to the pelvic floor
Its triangular base, the trigone
Describe the openings of the urinary bladder
The antero- inferior end of the trigone has the urethral opening (bladder neck),
where as the ureters enter at the 2 posterolateral angles
Describe the course of the ureters in the pelvis
They run down the posterolateral aspect of the pelvis, crossing its brim at the bifurcation of the common iliac arteries
They run anteromedially, inferior to the vas deferens in the male and to the broad ligament and uterine artery in the female to reach the base of the bladder
Why are the relation of the ureters in a female important
They run past the ovary, uterus, inferior to the uterine artery, and alongside the vaginal fornices
How do the ureters enter the bladder
Obliquely, running through the muscle and under the mucosa, creating a flap valve to prevent back flow of urine
What is vesicoureteric reflux
What prevents this
Back flow of urine into the ureter
A flap valve
How is the bladder neck anchored
Where is it anchored to
By pubovesical (female) or puboprostatic (Male) ligaments
To the pelvic floor and body of the pubis
What are the bladder walls composed of
The detrusor muscle
What happens to the detrusor muscle when the bladder is full in infants
Contracts reflexly
What relaxes when the bladder is full
The internal sphincter at the urethral opening
Which parasympathetic nerves supply the detrusor muscle
The pelvic splanchnics
S2–4
Why is there sympathetic flow to the bladder neck in males
For closure during ejaculation
The mucosa of the renal pelvis, ureter, bladder and proximal urethra is lined by what kind of epithelium?
Why
Transitional epithelium
It can withstand the toxicity of urine and accommodate a high degree of stretching
In females the base of the bladder supplied by which artery
Vesical branches from the uterine arteries
What is the venous drainage of the bladder
To a vesical plexus at the base of the bladder, and then to internal iliac veins. In the mail, there is also drainage via the prostatic Venus plexus
Describe the path of rectum
Begins anterior to S3. Passes downwards in the sacral concavity and turns forwards at the coccyx as the dilated ampulla. After a short course it bends sharply backwards to pass through the pelvic diaphragm and puborectal sling to become the anal canal in the perineum
What is the rectum mainly supplied by
The superior rectal artery, the middle rectal artery may give additional supply to the muscular wall
The superior rectal artery is a continuation of which artery
What about the middle rectal artery
The inferior mesenteric artery
The middle rectal artery is a branch of the internal iliac artery
Preganglionic fibres to the rectum arise from which spinal cord segments
Parasympathetic supply to the rectum is from where
L1 and L2
S2–4
In the Male , what does the urethra pass through after exiting the bladder
The prostate gland
What is the seminal colliculus
When the posterior wall of the prostatic urethra pushes forward into the urethral lumen
It is also called the verumontanum
What does the prostate do as the urethra passes through it
Adds its secretions to the seminal fluid via numerous ducts that open into the urethra on either side of the colliculus
What is the prostate gland connected to other than the urethra
How
It is connected to the posterior part of the pubis by the right and left puboprostatic ligaments
What is the arterial blood supply to the prostate
From the inferior vesical and middle rectal arteries
Describe the course of the vas deferens in the abdomen and pelvis
Enters the abdominal cavity at the deep inguinal ring and crosses the medial surfaces of the external iliac vessels and the pelvic brim to enter the pelvic cavity. At the posterosuperior corner of the bladder it turns medially and runs towards the midline. Posterior to the bladder is dilated to form the ampulla it’s narrow at the base of the prostate and two nights with the doctor at the salon all the circle at the same side to form the ejaculatory duct
Describe the course of the last ejaculatory duct through the prostate
The two ducks PS the prostate and run obliquely through it open onto the seminal colliculus
What is the vas deferens supplied by
“The artery to the vas “
Usually a branch of the superior vesical artery Which accompanies the lower pole of the epididymis
What supplies the seminal vesicles
Branches of the inferior vesical arteries
What is the nerve supply to the intrapelvic vas and the seminal vesicles
What about the vas in the spermatic cord
The same as the bladder
Same as the testes
What supports the testes
The pedicles of the spermatic cord
What do the testes produce
Spermatozoa and male hormones
What is the tunica vaginalis
As the testes descend from the past area abdominal wall in utero they draw with them the overlying peritoneum, forming a double layer around each testis
Describe the structure of the testis
The upper pole of the testis is the head of the epididymis, whose body lies posteriorly and his tail is continuous with the vas deferens
What covers the testis
A tough fibrous tunica albuginea which aids the movement of spermatozoa into the epididymis
What is the blood supply to the testes
Venous drainage? How does this differ from left to right?
The testicular artery
Via a pampiniform plexus to the testicular veins
Right: the testicular vein drains into the IVC
Left: drains into the left renal vein
Where do the lymphatics from the testis drain
To the para aortic nodes
Where is pain from the testis referred to?
Why?
Periumbilical region
Viscera afferents run with sympathetic efferents derived from T10
Describe the parasympathetic supply to the testes
There is no parasympathetic supply
Describe the uterine wall
Thick and fibromuscular
What does it mean to say the uterus is anteflexed
It is inclined forwards in relation to the cervix
How is the uterus divided? briefly describe each section
Fundus – the broad upper end which is covered by peritoneum
Body - where the uterine tubes are attached at the cornua
Cervix- which projects into the vagina
Describe the cervix
Upper and lower ends of cervical canal are called the internal and external os respectively
In most women, the lower cervix is invaginated into the anterior wall of the vagina at a right angle (ie anteverted)
True or false: the uterus is mobile
True
What is the fornix
Part of the vagina that envelopes the cervix and is circular in shape
How is the fornix divided for descriptive purposes
Anterior, posterior, and two lateral fornices
How is the fallopian tube divided for descriptive purposes
- Interstitial part
- Isthmus
- Ampulla
- Infundibulum
Describe the interstitial part of the uterine tubes
Lies within the uterine wall
Describe the isthmus part of the uterine tubes
Nearest to the uterus with a v narrow lumen
Describe the ampulla part of the uterine tubes
Lateral to the isthmus and characterised by gradual widening
Describe the infundibulum part of the uterine tubes
Widens significantly and opens into the peritoneal cavity
Contains fimbriae at its distal edge
What are fimbriae
Finger like projections in the infundibulum
One fimbria connects to the uterus
They are partly erectile and grasp the ovary at at the time of ovulation
Which artery supplies the uterus
Describe its course
Is there additional arterial supply?
The uterine artery
Passes medially and in the base of the broad ligament to reach the uterus, across and above the ureter
Yes from the ovarian branches of the abdominal aorta
Where does the sympathetic innervation to the uterine tubes come from
Parasympathetic?
Preganglionic axons originating in the T10 – L1 spinal-cord segments which synapse at the hypergastric plexuses
From pelvic splanchnics
What are the pelvic splanchnic nerves
parasympathetic outflow from S 2–4
What is the uterus covered by
On which surfaces
By visceral peritoneum
Anterior, superior, posterior
Where do the anterior and posterior ligaments meet on the uterus
What happens here
Inferior borders of the tubes
And
Lateral borders of body
The peritoneal layers meet and extend as a double fold to the parietal peritoneum at the pelvic floor and on the lateral pelvic wall. This is called the broad ligament
What is the bilayer made by the meeting of the anterior and posterior peritoneal layers in the uterus called
Broad ligament
Describe the round ligament
A ligament that extends from the junction of the uterus and the tube to the labia majora of the vulva
Describe the course of the round ligament
At first runs between the layers of the broad ligament, then crosses the pelvic brim to enter the deep inguinal ring and pass through the inguinal canal
What is the pubocervical ligament
Consists of fibres passing from the pubis anteriorly around the bladder to the cervix
What is the cardinal ligament also called
The transverse cervical ligament
Describe the Cardinal ligaments
Connective tissue bands which run in the broad ligament from the lateral pelvic wall to the junction of the cervix and vagina
Describe the uterosacral ligaments
They run both sides of the uterine isthmus to the sacrum. Each ligament runs lateral to the rectum and raises a visible ridge in the parietal peritoneum
What occurs below the ampulla of the uterine tube
The ovary bulges out from the posterior layer of the broad ligament
What is attached to the ovary below the ampulla of the uterine tube
A small mesentery, the mesovarium
What occupies the ovarian fossa
What is immediately behind that fossa
The mesovarium
The ureter
Where is the obturator neurovascular bundle
Lateral to the ovary right
What is the suspensory ligament of the ovary
A raised part of the broad ligament which transmits the ovarian vessels and lymphatics
Where does the ligament of the ovary run
Between the layers of the broad ligament,
it runs from the ovary to the uterus at the level of the uterine tube
It is then continuous with the round ligament
What is the female equivalent of the Male gubernaculum
The ligament of the ovary and the round ligament
What is the ovary supplies by, arterially
What does it anastomose with
Ovarian artery
The uterine artery
Which veins drain the ovary
A venous plexus in the mesovarium which drains into ovarian veins, accompanying the arteries
Drains into IVC on right and into left renal vein on right
Where do the lymphatics drain to from the ovaries
The para aortic nodes
What is the sympathetic supply of the ovaries
Where do they synapse
Arises from preganglionic axons from T10
In pre aortic ganglia at the origin of the ovarian artery
Where is ovarian pain referred
The periumbilical region
What is the parasympathetic supply to the ovary
There is none
How can you puncture a bladder in cases of urinary retention
When the bladder is fully distended it rises out of the pelvis into the abdomen, stripping the peritoneum upwards from the anterior abdominal wall. Therefore, an extra peritoneal suprapubic puncture can be made into a full bladder
How can the prostate be examined in men
What else can be examined
Digital rectal exam enables assessment of the posterior surface of the prostate gland
Seminal vesicles but is not always possible
When can a vaginal exam not be performed
What is done instead
Eg in children
Rectal examination is done primarily to provide info about the rectouterine pouch and lower part of the body of the uterus to
Rectal examination can give info about posterior wall of vagina
How common is a carcinoma of the rectum
Very, it is one of the most common of the GI tract
What can happen with a rectal carcinoma
Initially localised to rectal wall but if untreated can extend into surrounding structures
If it extends posteriorly it can affect the sacral plexus, causing severe pain down the sciatic nerve
Lateral extension may involve the ureter
Anterior extension in males can affect the prostate, seminal vesicles and bladder; or the vagina and uterus in females
What does Testicular torsion involve
Where is it common
How is it treated
Rotation of the testis around the spermatic cord within the scrotum
In children and active young men
Emergency surgery is required as occlusion of the testicular artery will lead to testicular necrosis
What does severe labour pain arise from
Where is it referred to
Sustained uterine contractions
T10-L1
What does mild labour pain arise from
How is it referred
Cervical distension as the foetus starts its descent
Along parasympathetic nerves from the uterus to reach S3/4
What is the pain of delivery
Where is it referred to
Which nerves carry it? Give the spinal root
Somatic pain from perineal stretching
Sacral region
Pudendal nerve (S2-4)
How can all labour and delivery pain be eliminated
What is the most popular method
How is it effectiveness tested
By anaesthetising spinal nerves T10-S4
A lumbar epidural block
On the skin from the umbilicus (T10) to the perineum
Is there a connection between the external environment and the peritoneal cavity
Only in females, via the vagina, uterus, uterine tube
How is the connection between the external environment and the peritoneal cavity usually kept closed
By the lining of the uterine tube, the narrow aperture of the uterus and the interdigitating folds of the cervical canal
Which muscles form the pelvic floor
The levator ani
Coccygeus
What are anococcygeal and perineal bodies
Thickenings of the midline raphé of lavator ani
True or false
The perineal body has no known function
False
It is indispensable to the support of the pelvic viscera
What does the perineum consist of
The part of the pelvic outlet that lies causal to the pelvic diaphragm
What divides the perineum
What is it divided into
A line joining the anterior parts of the ischial tuberosities
Into a large posterior triangle and a smaller anterior urogential triangle
In the female what do the urethra and vagina pass through anteriorly
Urogential hiatus
What does the anal canal pass through
The rectal hiatus
What are the Urogenital hiatus and the rectal hiatus known as collectively
Why
Levator hiatus
They line between the musculature of levator ani
What does the anal triangle contain
Anal canal and the ischioanal fossae
Where does the anal canal again
That’s the pelvic floor, at the level where the puborectalis muscle sling creates the anorectal angle
What are the three parts of the external anal sphincter
Deep, superficial, and subcutaneous
What are the ischioanal fossae
How are they separated medially
Pyramidal, Fatfield spaces between Levitor ani medially and the pelvic walls laterally
By the perineal body, anal canal and the anococcygeal body
What is the perineal membrane
What is its function
A thick fascial, triangular structure attached your pubic arch
To provide support for the external genitalia, which are attached to its inferior surface
What is each corpus cavernosum attached to
The ischiopubic ramus by a crus which is covered by the ischiocavernosus muscle
What does the urethra pass through in the penis?
Corpus spongiosum
When do the three bones of the hip fuse
16th year of life
How many vertebra are in the sacrum and coccyx respectively
Sacrum: 5
Coccyx: 3-4
Where does piriformis arise from
The middle three pieces of the sacrum and the adjoining lateral mass, extending medially between the anterior secret foramina
How does piriformis leave the pelvis
Where does it insert
By passing through the greater sciatic foramen
On the upper surface of the greater trochanter
What does obturator internus arise from
The membrane and bony margins of the obturator foramen
Describe the course of obturator internus
Include its insertion
Its tendon makes a sharp turn to pass through the lesser sciatic foramen, where a bursa lies between tendon and bone. It inserts onto the medial surface of the greater trochanter.
Describe levator ani
Sheet of muscle arising from the pubic bone and obturator internus fascia
It is subdivided into three parts: puborectalis; pubococcygeus; iliococcygeus.
Describe puborectalis
Arising from the posterior surface of the pubis to form a sling at the anorectal junction, it plays an important role in maintaining faecal continence
Where does pubococcygeus arise and insert
Arises from posterior surface of the pubic
Inserts into the anococcygeal raphé
What does pubococcygeus comprise
Puboprostaticus (Male)/ pubovaginalis (female)
And
Puboanalis
Where does iliococcygeus arise and insert
Arises from the white line on the obturator internus and the ischium
Inserts into the anococcygeal raphé
What is the arcus tendineus
The white line on the obturator internus fascia
Where does coccygeus arise and insert
How is it arranged
Arise: ischial spine
Inserts: lower part of sacrum and coccyx
Its fibres lie parallel to the sacrospinous ligament but the muscle is anterior to it
What is the nerve supply to coccygeus
From branches of S3 and S4 and from pudendal nerve
What are the borders of the perineum
The pubic symphysis anteriorly, the ischial tuberosities laterally, and the coccyx posteriorly
What does the perineal membrane stretch between
The ischiopubic rami
Why is the apex of the perineal membrane missing
To leave a gap for the pubic symphysis
What is the perineal membrane anchored to
Posteriorly to the perineal body in the midline and is attached to Colles’ fascia
What is Colles’ fascia
The continuation of Scarpa’s fascia
What pierces the perineal membrane
The urethra, the vagina in the females, and foramina the nerves and vessels
What is the perineal body
What is it formed by (4)
A fibromuscular mass of tissue lying in the midline between the Urogenital and anal triangles
It is formed by the interdigitating fibres of puboprostaticus or pubovaginalis,
the superficial and deep transverse perineal muscles,
part of the external anal sphincter,
and bulbospongiosus
What is the perineal body often known as
Why is it important
The central tendon of the perineum
Maintaining the integrity of the pelvic floor and perineum
What are the spaces of the perineum described as
The deep and superficial perineal pouches
What is the deep perineal pouch defined as
The space immediately superior to the perineal membrane
What are the boundaries of a deep perineal pouch
It is bounded above by the inferior surface of Levator ani, but no distinct fascial layer exists here
What does the deep perineal pouch contain
The membranous urethra
External anal sphincter
Bulbourethral/ Carper’s glands
Deep transverse perineal muscle
Anterior prolongations of the ischioanal fossae
Nerves and vessels of the penis and clitoris
What defines the superficial perineal pouch
The space enclosed between the perineal membrane and Colles’ fascia
What does the superficial perineal pouch contain
External genitalia, three muscles,
the great vestibular/Bartholin’s gland in the female
What are the external genitalia
Testes, spermatic cord, penis, or clitoris
What are the three muscles of the superficial perineal pouch
Ischiocavernosus,
bulbospongiosus,
superficial transverse perineal muscle
What does the anal triangle contain
The anal canal and the ischio anal fossae
What are the lateral boundaries of the anal triangle
The sacrotuberous ligaments
What are the sacrotuberous ligaments covered by
The lower border of Gluteus maximus
What is the base of the anal triangle
Apex?
A line joining the anterior part of the ischio tuberosities
the apex is the tip of the coccyx
Where does the anal canal extend from to?
Extends from the right angled anorectal junction at the puborectalis sling of Levator ani to the anocutaneous junction
What divides the anal canal
The pectiante line (AKA dentate line)
How does the dentate line divide the anal canal
It divides the upper 2/3 which is lined with mucus membrane, from the lower 1/3 which is lined with skin
What is the up at 2/3 of the anal canal covered with?
Lower 1/3?
Upper: mucous membranes
Lower: skin
What does the division of the anal canal reflect
The different embryological origins of the two parts (endoderm versus ectodermal)
What is different about the two different parts of the anal canal other than what it is covered in
Blood supply: superior versus inferior rectal arteries,
innervation: autonomic versus somatic
lymphatic drainage: internal iliac nodes versus superficial inguinal nodes
Where is the internal anal sphincter
What is it
Surrounds the upper 2/3 of the anal canal
A thickening of the circular muscle of the rectum
True or false: the internal anal sphincter are supplied by sympathetic fibres
True
Describe the different parts of the external anal sphincter
Deep: fused posteriorly with puborectalis
superficial: attached anteriorly to the perineal body
subcutaneous: lying deep to the perianal skin
What is the anal canal surrounded by on all sides? What does that allow?
Fatty connective tissue which allows it to expand easily as faecal matter and is it
The space containing the fatty tissue is ischioanal fossa
What are the boundaries of the ischio anal fossa
The ischial tuberosities and the anal canal
What important structure is in the lateral wall of each ischio anal fossa
What does the structure contain
The pudendal canal
Contains the internal pudendal vessels and the pudendal nerve
What do the structures in the pudendal canal give
The inferior rectal vessels and nerves
Are the ischio anal fossae continuous each other
Yes anterior and posterior to the anal canal
What are the anterior recesses of the fossae
The fat within each ischio anal fossa extends forwards between the upper surface of the perineal membrane on the lower surface of the pelvic diaphragm on the lateral sides of the external urethral sphincter
What is the Mons pubis
A fatty protuberance over the pubic symphysis
Describe the labia majora
Hair bearing folds extending posteriorly from the mons
Describe the labia minora
Inner hairless folds united posteriorly at the fourchette
What is the vestibule
The space between the labia minora, into which the urethra opens anteriorly and the vagina posteriorly
Describe the clitoris
A small mass of a erectile tissue, which lies anteriorly to the urethral opening and is attached to the ischio pubic ramus by the ischio cavernosus muscles.
It is homologous to the penis, with two corpora cavernosa and a small glans
What does the vestibular bulb consist of
Two erectile tissue masses superficial to the perineal membrane on each side of the vaginal opening.
They are covered by bulbospongiosus.
Posterior to the bulb are the two mucus secreting greater vestibular glands which drain anteriorly
Describe Bartholin’s glands
Also known as the greater vestibular glands
They are posterior to the vestibular bulb and up to mucus secreting glands which drain anteriorly
How is the penis divided
Into the root, body, and glans
Describe the root of the penis
The route is attached to the perineal membrane, the crura to the ischiopubic ray my and there is a suspensory ligament from the pubic symphysis
What does the body of the penis consist of
Two lateral longitudinal columns of erectile tissue (corpora cavernosa) separated by an intervening septum, and the ventral corpus spongiosum which colour in gorge but it is not truly erectile
Which parts of the penis are erectile
The corporate cavernosa (not the corpus spongiosum)
Describe the crura of the penis
The corpora cavernosa diverge posteriorly to form the crura, which is covered by the ischio cavernosus muscle
Where does the corpus spongiosum begin
How does it continue
At the perineal membrane as an enlargement (the bulb)
This runs forward in a groove on the inferior surface of the corpora cavernosa
What surrounds the bulb of the penis
The bulbospongiosus muscle
How is the glans of the penis formed
By an expansion of the corpus spongiosum over the corpora cavernosa
What can you find on the tip of the glans of the penis
The external urethral meatus
How is the foreskin of the penis attached
The prepuce Is attached to the glands below the meatus by the fraenulum
What is the prepuce
The foreskin
What is the scientific name for foreskin
Prepuce
What is the fraenulum of the penis
A fold of mucous membrane that attaches the prepuce to the glans
What’s around the entire body of the penis
A deep fascial sleep known as Buck’s fascia
What is Buck’s fascia continuous with
The septum between the corpora cavernosa and suspensory ligament
Where does the male urethra extend from
From the internal urethral meatus to the external urethral meatus on the tip of the glans of the penis
How long is the male urethra?
15 to 20 cm long
How is the male urethra divided for descriptive purposes?
Into three parts: the prostatic part, the membranous part, the spongy part
Describe the prostatic part of the urethra
This is the widest part, which passes through the prostate gland.
There is an elevation, the seminal colliculus on the posterior wall. The ejaculatory ducts open onto its summit, while the prostatic ducts open into the grooves on the sides
Where did the prostatic and ejaculatory duct open onto the urethra
Prostatic: into the grooves on the sides
Ejaculatory: onto the summit
What is the vermontanum
The seminal colliculus of the Male urethra
Describe the membranous part of the Male urethra
It is the shortest and most rigid part. It passes through the deep perineal pouch, where it is surrounded by the external urethral sphincter, and then through the perineal membrane to become the spongy urethra. Embedded in the sphincter muscle are the two bulbourethral glands which secrete secrete a lubricant fluid
What are the bulbourethral glands
To gland is embedded in the external urethral sphincter which secrete a lubricant fluid
Describe the spongy part of the urethra
It Is also known as the penile urethra, this part runs in the corpus spongiosum to the tip of the glans
It’s lumen is transverse, except at the external urethral meatus, the narrowest part of the urethra, where it is vertical, just giving a spiral stream of urine
What makes the urine stream spiral
The lumen of the spongy part of the urethra is transverse except at the external urethral meatus, where it is vertical
Urinary continence is largely dependent on what?
The external urethral sphincter
What supplies the external urethral sphincter
The perineal branch of the pudenda nerve
Describe the scrotum (3)
A pouch of thin rigid skin enclosing the testes
There is a median Raphé in the skin and a fibrous midline septum which separates the scrotum into two cavities
A layer of smooth muscle lies in the subcutaneous tissue
What do you call the layer of smooth muscle in the scrotum
What is its action
The dartos
Contraction of this muscle is in voluntary and results in increased wrinkling of the scrotal skin
Describe the innervation of the scrotum
The anterior one third of the scrotum is applied by a branch of the ilioinguinal nerve while the scrotal branch of the pudendal nerve surprise supplies the posterior 2/3
The coccygeal plexus is formed by …?
A branch from us for, the anterior primary ramus of S5 and the coccygeal Nerve
Which 2 nerve plexuses lie in the posterolateral wall of the pelvic cavity
What do they innervate
The sacred plexus and the coccygeal plexus
the lower limb, and the muscles of the pelvis and the perineum
Where does the pudendal nerve come from
What dies this nerve supply
The anterior a mind of S2-4
The perineal muscles and skin
Why must the pudendal nerve accept the pelvic cavity? How does it do this?
The perineum lies below the pelvic diaphragm
It leaves through the greatest sciatic foramen below with the lower border of piriformis
Describe the course of the pudendal nerve after leaving the greatest sciatic foramen
It winds over the sacrospinous ligament to pass through the last sciatic fireman to enter the perineum. The nerve embeds itself within the obturator fascia in a fascial tunnel, the pudendal canal
Give the old name for the pudendal canal
Alcock’s canal
Give the three branches of pudendal nerve
Inferior rectal
, perineal,
dorsal nerve of the penis or clitoris
Describe the inferior rectal nerve
Arises in the posterior part of the pudendal canal.
Passes medially over the roof of the ischioanal fossa and gives branches to supply the external anal sphincter are pairing how are you anal skin. Also gives branches to supply levator ani
Describe the perineal nerve branches
It divides into the following branches: the scrotal/labial branches; Muscular branches; nerve to the bulb
Describe the scrotal/labial branch of the perineal nerve
The medial branch passes with the scrotal or labial artery to supply the scrotum or labia; the lateral branch also gives crunches to the anus
Discussed the muscular branches of the perineal nerve
supply the transverse perineal muscle
What are the transverse perineal muscles
Ischiocavernosus
Bulbospongiosus
External urethral sphincter
Levator ani
What does the nerve to the bulb from the perineal nerve supply
The bulb of corpus spongiosum
What supplies the skin at the root of the penis/clitoris
What other Male part is supplied by this
The anterior scrotum/labial branches of the ilioinguinal nerve
The anterior part of the scrotum
True or false
the erectile bodies of the penis supplied by its dorsal nerve
False: they are supplied by branches of the pelvic plexus
What is episiotomy
The procedure of incising the posterior wall of the vagina, and the skin behind it, in order to prevent ragged tearing of the perineal tissue and the risk of anal incontinence during and after childbirth
What is a vasectomy
What does it mean
When the vas deferens is ligated in the superior part of the scrotum.
Sperm production still continues but spermatozoa can’t reach the urethra
Which nerve is often blocked during delivery
Why is this useful
The pudendal nerve
Provides analgesia, and pelvic floor relaxation in forceps delivery
What does pain during the second stage of labour result from
Distension of the lower vagina, Vulva, and perineum
When is a pudendal nerve block used other than delivery
To provide Anastasia of the perineum in order to create or repair an episiotomy
What is the most common method to give a pudendal nerve block
The transvaginal approach: inserting a finger and needle, protected by God, into the vagina. The ischial spine Is palpated and the needle is pushed through the vagina mucosa and sacrospinous ligament in order to infiltrate the tissue around the pudendal nerve
What can be dangerous during the transvaginal approach at applying a pudendal nerve block
While the position of the internal pudendal artery means crossing the ischial spine is usually safe, one must always withdraw the plunger of the syringe to verify that the artery or vein has not been entered
True or false ischio anal abscess are relatively common
True
How do you treat an ischio anal abscess
Is there danger?
They must be drained by incising the skin just lateral to the anal canal
Not really: the inferior rectal nerve and vessels are usually well out of harms way, what is their existence must be remembered
Name a common site for traumatic urethral rupture
What are the signs of this
The junction of the mobile penile urethra with the fixed membranous urethra
This produces bruising and extravasation of urine into the superficial perineal pouch, giving a swimming trunks 🩳 appearance
Why does bruising from perineal injury result in the appearance of a pair of swimming trunks
Colles’ and Scarpa’s fascia are continuous
Why is the female urethra not subject to the same trauma as in males
It is straight and opens onto the surface almost immediately after piercing perineal membrane
What are the Nervi erigentes
Why
What are they referred to surgically
The pelvic splanchnic nerves
They carry preganglionic parasympathetic axons that, upon simulation, produce erection
The cavernous nerves
Describe the course of the pubic splanchnic nerves in males
Postganglionic fibres descend inferiorly along the posterolateral aspect of the prostate gland
They run next to a prostatic artery and vein forming a neurovascular bundle.
Below the apex of the prostate the nerves pass on to the lateral aspect of the external urethral sphincter and then on the membranous urethra which they follow through the perineal membrane to reach the corpora cavernosa
Operations on the rectum and prostate may put which nerves at risk
The pelvic splanchnic nerves (Nervi erigentes)
How is the term ‘pelvis’ commonly used
To denote the pelvic girdle and the cavity contained within the girdle
What is the greater pelvis
Formed on each side by the wing of the sacrum and the fan shaped iliac fossa
AKA fake pelvis
What is the true pelvis
Formed by the sacrum posteriorly, the pubic bones anteriorly and the inner surface of the ischium and a small part of the ileum laterally
AKA lesser pelvis
What is the pelvic inlet
The plane separating the true and false pelvises, being the sacral promontory, the iliopectineal lines and the superior border of the pubic symphysis
What is the pelvic outlet
The lower margin of the true pelvis, bounded by the coccyx, the ischial tuberosities and the inferior border of the pubic symphysis
The pelvic girdle is made up of what
The pad bones and the single sacrum
How is the weight of the upper body transferred in the pelvis
It is transferred from the fifth lumbar vertebra to the sacrum and then across the roof of the acetabulum and the head of the femur when standing
Or
To the ischial tuberosities when sitting
To achieve the transfers of weight how is the pelvic girdle constructed
As a series of archers, with the kings of the bones along the lines of force while other parts of the bones are very thin
Give an example of a thin part of the pelvic girdle
The ala of the ilium
In both sitting and standing, weight is transmitted across which joint
What kind of joint is it
The sacroiliac joint
Synovial
There is a tendency to wait to cause rotation of the sacrum around where?
What does this do
How is this resisted
S2
Drives the sacral promontory anteriorly and inferiorly
The sacrum is wedge shaped (wider posteriorly than anteriorly) and has an interlocking ridge and groove across the articular surface
It also has strong ligaments
What are the strong ligaments that hold the sacrum in place
What happens to these during pregnancy
Sacroiliac
Sacrotuberous
Sacrospinous
They soften under the influence of progesterone to allow movement of the joint during childbirth
Why do the ligaments of the sacrum soften during childbirth
By allowing rotation of the joint you can increase the dimensions of the pelvic outlet
Describe the pelvic diaphragm
Closes off the inferior Boundry of the abdominal pelvic cavity
Concave superiorly, funnelling pressure towards the opening of the urethra, anal canal and vagina which perforate it in the midline
Comprised of levator ani and coccygeus
Where do levator ani and coccygeus attach
From the body of the pubis to the ischial spine
What do you projections of the ischial spines and the coccyx towards the centre of the pelvic diaphragm do
Increase the support available
What does the pelvic floor support
The bladder and rectum and the muscle tone is important in the maintenance of continence
Also uterus in females to prevent prolapse
What is the conflict in the female pelvis
Between providing bony support for the pelvic diaphragm and allowing space for the head of the human fetus
Give five sex differences in the pelvis
Length of pubic ramus
Tightness of greater sciatic notch
Size and degree of inversion of the ischial spines
The width of the sacral ala
The curvature of the sacrum
What is the longest dimension in the pelvic inlet in females
Outlet ?
The transverse diameter
Anteroposterior diameter
How big is the biparietal diameter of the feral head
~9.5cm
Where does the face point at birth
Posteriorly
Why does the fetal head rotate 90° as it passes through the outlet
The shoulders of the next widest part of the fetus so must follow the same rotation through the pelvic inlet
Why is a maternal diet important for delivery
Poor maternal diet leading to Rickets can cause defamation of the birth canal and obstruct labour
What shape is the bladder
What is it covered by on its superior surface
Pyramid
Peritoneum
When does the bladder rise above the pubic symphysis
And young children, in men with chronic obstruction of the urethra, and pregnant women
What spinal level does the rectum begin
S3
Which muscle maintains the anorectal junction angle
Puborectalis
Describe the covering of the rectum
The upper third has peritoneum on the anterior and lateral aspects
The middle third on the anterior aspect only
And the lower third is retroperitoneal
Why is it important to know the positions where the covering of the rectum changes
It is a common site for carcinoma and these reflections have an important bearing on the region that can be excised and end to end anastomosis performed
How is the uterus divided simply
Body : upper 2/3
Cervix: lower 1/3
What is the fornix
And annular recess created by the cervix projecting into the vagina
Describe the cervical canal in nulliparous women
The canal is normally aligned at approximately 90° to that of the vagina, the anteverted position, so that the posterior part of the fornix is usually deeper than the anterior part
Which ligaments support the cervix
Which wall of the pelvis does each run to
Uterosacral (to posterior wall of pelvis)
Transverse cervical (lateral)
Pubocervical (anterior)
In pregnancy when does the uterus become palpable
Where
12 weeks
Above the pubic symphysis
When does the uterus reach the xiphisternum
36 weeks into pregnancy
After the uterus has reached the xiphisternum in pregnancy when does it drop again
It dropped a couple of centimetres once the fetal head has entered the pelvic cavity
Which abdominal wall provides important support during pregnancy
Anterior
What happens to the second arch formed by the pubic bones when standing and sitting
It is in compression in the standing position and in tension in the sitting position
How is the pelvis rotated compare to other apes
It is rotated anticlockwise and flattened anteroposteriorly
When does the sacroiliac joint fuse
~50years
Plane of the pelvic inlet is inclined at what angle?
Outlet?
60°
10–15°
How are the sacral wings and curvature of the sacrum different in females
How is the pubic ramus different? What does this mean?
How is the sciatic notch different
Increases width of wings
Less curvature
Length of ramus is greater than width of acetabulum (equal in males) meaning the suprapubic angle is >90 degrees in females and <90 in males
Greater opening of the greater sciatic notch and reduction in the size and inversion of the ischial spine in females
What is the problem of bipedalism on the birth canal
Bipedalism evolved before the increase in the size of the human brain and skull could accommodate it
What is it called when the human brain increased in size due to evolution
Encephalisation
Does rotation occur in chimpanzee birth
No
Give an abnormal fetal lie in the uterus which will not go through the pelvis
Brow presentation which is 14cm in diameter
What is the danger in breech delivery
That the body may pass through but not the head so delivery delivery cannot be completed although placental circulation may have been cut off
How come the size of the pelvic outlet be increased
By rotation of the sacroiliac joint permitted by softening of the ligaments during pregnancy
Squatting helps rotate the joint as does pulling up the legs
There is also a softening of the pubic symphysis that may increase the dimensions of the birth canal
What tool can be used to fix malrotation of the head in delivery
Forceps
What is obstructed or prolonged labour associated with
Fetal hypoxia
Why is the recto uterine pouch important
It is important route for endoscopic access to the pelvis
Many procedures can be carried out by this route
Do the bladder and uterus lie above or below the plane of the pelvic inlet
What does this mean
Below
They cannot normally be palpated abdominally
Who discovered x-rays and when
What was the first ever radiograph of
What award did he win
Röntgen in November 1895
His wife’s hand
1901 Nobel Prize in physics
How are x-rays generated
When electrons accelerated at high velocity collide with a metal target
Materials with a high electron density tend to _____ an x Ray beam through absorption
Attenuate
Name an element with high electron density that is readily found in the human body.
Calcium
Give the four things which maintain rectal continence
Internal anal centre
External anal centre
Pelvic floor complex of muscles
Anal cautions in upper half of anal canal and general apposition of mucosal folds
What is the first part of defecation
How is this felt
Mass movement into the rectum induced by a gastrocolic reflex
This induces a sensation of fullness (general visceral afferents in ANS)
Give the steps of defaecation (6)
Mass movement
Sitting and relaxing the pelvic floor and external anal sphincter is to decrease anorectal angle
Valsalva Manoeuvre
Anal pressure reflexly increases and the colon and rectum continue to contract, distending the rectum
The pressure in the rectum reflexly relaxes the internal anal centre the rectum and shortened by its longitudinal muscle
Finally the external anal sphincter are reactors and the anal canal opens. Anal mucosa temporarily at everts and evacuation is completed
What happens to the anal canal after evacuation is completed
Give the type of innervation necessary
The closing reflex
Contraction of the pelvic floor including puborectalis, (somatic) external anal sphincter (somatic), internal anal sphincter (sympathetic)
How does faecal incontinence present
With either a sudden uncontrollable urge (suggesting a rectal contraction)
passive leaking without warning often on moving (likely sphincter weakness or senility)
Soiling (leaking or poor hygiene )
How common is faecal incontinence
Describe the difference between the sexes
10 to 15% suffer and worsens with age
No sex differences over the age of 40 but in younger females it can be related to childbirth by vaginal delivery
What is one of the major reasons for admission to residential care
Faecal incontinence
What is often the cause of faecal incontinence in the elderly
How may it present
What is it associated with
General physical and/or cognitive decline
As diarrhoea or constipation, suggesting that consistency of faeces is an important factor
Inflammatory bowel disease, irritable bowel syndrome, drugs such as laxatives, antibiotics and some foods
Which foods are associated with faecal incontinence
Prunes, beans, artichokes
Sphincter problems later in continents in what percentage of women after vaginal delivery and for how long
What are aggravating factors
30%
3-6 months
Obesity
Use of forceps
Prolonged labour
What percentage of women whose sphincters tear at delivery have ongoing faecal incontinence problems
85%
Name some diseases that might lead to faecal incontinence (8)
Haemorrhoids
Neurological diseases e.g. MS, diabetes
Spina bifida
Anal atresia
Hirschsprung’s disease
Rectal prolapse
Degeneration of pelvic floor and prolapsing piles
Also surgery for cancer in the anal area
How can you investigate the cause of faecal incontinence
Digital anorectal examination can give information on tone of symptoms, possible injury, constipation, pressure on rectum from other organs and tumour in prostate or rectum
Colonoscopy
Ultrasound and MRI
nerve and muscle conduction studies
Assessment of mental state is essential
Always consider the possibility of a central prolapsed disc
What is the nonsurgical treatment for faecal incontinence (9)
Treat anxiety and depression
Diet (Low residue diet) and timing of meals (gastrocolic reflex)
Fibre supplements to give bulky stalls
Drugs (loperamide, codeine phosphate)
Treat overweight
Anal plug stimulation
Absorbent pads
Pelvic floor exercises
Rectal irrigation
Give 4 surgical treatments for faecal incontinence
Sacral nerve stimulation
Sphincter repair
Artificial sphincters (gracilis sling)
Diversion with colostomy
What are the four continence factors of urinary control
Muscles (pelvic floor, bladder, urethra)
Lateral pressure on urethra
Compliance
Nerve control
Describe compliance in urinary control
Visco-elasticity gives the bladder The ability to relax and accommodate increasing amounts of urine with no rise in pressure
This viscoelasticity is different from normal or true elasticities as seen for instance one blowing up a balloon
What limits the compliance of the bladder
Filling to fast
Filling to full
Too thick
Abnormal nerves
What do we need for perfect urinary control
A good capacity bladder with viscoelasticity
Normal nerve control and adequate sphincters that can contract and relax
At least some of that urethra must be within the abdominal cavity to allow lateral intra abdominal pressure to act upon it
Without abdominal pressure on the urethra what is likely to happen
Stress incontinence
What is the bladder
Smooth-muscle organ that must collect and start urine at low pressure is then periodically expel it via a highly coordinated and sustained contraction
What is needed for expulsion of urine
A long, coordinated, sustained contraction of the bladder and a reduction in resistance of the bladder neck and sphincters (i.e. an unobstructed urethra)
What are the sequence of events for voiding urine
First there is either voluntary relaxation of pelvis muscles at the present of an over full bladder. Both can lead to a lowering of pressure in the urethra
The water pressure than reflexly increases and then bladder neck opens
Voiding begins and completes
The stream can be shut off midstream by contracting the voluntary sphincters
Name the seven factors of urinary continence
Sphincters: around urethra and bladder neck
Intrinsic urethral mechanism
Elastic tension in urethra
Watertight seal of soft tissues
Pelvic floor muscles
Intra abdominal pressure acting laterally on urethra
Compliance with viscoelasticity
What does it mean if someone presents with urinating too often with increased frequency and urgency
Either: unstable/overactive bladder or a small bladder
Describe an unstable bladder
Very common
Bladder contract when it shouldn’t
Poorly understood
Possibly psychological or a nerve problem
Why might someone have a small bladder
This is rare and will occur after infection or cancer or surgery or radiotherapy
What does it mean if a patient finds urinating too difficult and there is a poor stream
There may be a mechanical obstruction or a weak bladder
Describe mechanical obstruction leading to a poor stream of urine
Maybe prostate which is very common
Nerve problems stopping Sphincter relaxing
Narrowing of urethra (rare)
Discuss having a weak bladder
There will be no pushing power which is fairly rare
The bladder will be big and floppy
The muscle may be overstretched
That might be poor nerve supply E.g. caused by slipped disc
Probable need for intermittent catheterisation
What is the volume of a weak bladder
> 650ml
What is the volume of a small bladder
<350ml
What can lots of control of bladder and wetting be caused by
Loss of compliance
Massive contractions with normal sphincters
Can be caused by laughing, nerve problems
An overactive bladder is particularly common in which kind of patient
Women
What might cause the bladder to have a weak sphincters
Surgical or nerve damage
this may lead to stress incontinence
What is stress incontinence
After childbirth very common
Incontinence occurs on coughing, laughing, straining and bending
How to treat stress incontinence
Pelvic floor exercises
Pilates
Surgery to pull the urethra back into the abdomen
Give five features of the sigmoid colon that stop before the rectum begins
Appendices epiploicae
Taenia coli
Sacculations
Haustrations
Mesentery
How long is the perineum on the rectum
12cm (4 sides and front, 4 front only, 4 below)
What are the shelves of mucosa and circular muscle in the rectum called
Valves of Houston
In constipation where are faeces stored
PUp at 2/3 of rectum as it is distensible and inside the abdominal cavity
Count the lower one third of the rectum distend
It can distend laterally into the ischio anal fossa during dedication
What is the longitudinal muscle of the rectum
To wide bands anteriorly and posteriorly
What is the anocutaneous reflex
Lightly Stroking the buttock skin near the anal canal should cause a reflex contraction of the voluntary external anal sphincter
True or false
The rectum is capable of distinguishing between air, water and faeces
True
Enlargement of what leads to haemorrhoids
Where are they
What do they do
What colour are they
Enlargement of the three spongy mucosal cushions that are in the upper half of the anal canal
At 3,7 and 11 o clock
They help with continents, airtightness and mucus production
Bright red with capillary blood
Why might the venous plexuses in the rectum enlarge
Due to portosystemic anastomoses
What is spurious diarrhoea
In severe constipation when the rectum is so blocked with hard faeces that only semi-fluid can reach the lower rectum
Sensation of fullness is disrupted by overdistention and there is leakage of thin faecal material
What does the intrinsic urethral mechanism do
Milks back the urine to the bladder neck
True or false
The bladder relaxes as it fills
True
What is flaccidity
Usually due to peripheral nerve damage
Once muscles have no nerve control they will not contract
What is spasticity
Brain or spinal injury e.g. in stroke
Fine control is lost but peripheral nerves can still function with no coordination this movement is jerky
Why do children adopt funny positions when the bladder contracts unwontedly
The bladder has not yet fully developed so lacks viscoelasticity
How can an enlarged prostate causing obstruction of the urethra be treated
Transurethral prostatectomy using a hot loop
