Region 7 - Pelvis Flashcards
Where does the bladder sit in relation to the pubic bones?
Posterosuperior
What does the bladder rest on?
Anteriorly: - Pubic bones and pubic symphysis Posteriorly: - Prostate (males) - Anterior vagina (females)
What features of the bladder inner surface allow stretching?
Transitional epithelium
Rugae
Where does the bladder lie in infants and children?
Abdomen (empty and full)
At what age does the bladder begin to lie in the greater pelvis?
6 years
Where does the bladder lie from puberty onwards?
Lesser pelvis when empty
Rises to suprapubic region as it fills
What connects the pubic symphysis to the apex of the bladder?
Urachus:
- Remnant of allantois; a canal draining foetal bladder via umbilical cord
What is the trigone of the bladder?
The inferoposterior, triangular base of the bladder
An internal area of smooth mucous membrane
What muscle encircles the orifices of the trigone?
Detrusor muscle
What is the alternative name for the internal urethral sphincter? What muscle is it a continuation of?
Sphincter vesicae (not complete) Detrusor muscle
What ligaments how the neck of the bladder in place?
Puboprostatic (males)
Pubovesical (females)
What is the blood supply to the bladder in males?
Superior vesical arteries (x2)
Inferior vesical artery
What is the blood supply to the bladder in females?
Superior vesical arteries (x2)
Vaginal artery
Where do the arteries that supply the bladder arise from?
Superior vesical arteries:
- Patent umbilical artery (anterior division of internal iliac artery)
Inferior vesical/vaginal artery:
- Anterior division of internal iliac artery
What arteries can give small branches to the bladder?
Obturator artery
Inferior gluteal artery
What is the venous drainage of the bladder?
Vesical plexus -> Internal iliac vein
What provides SNS innervation to the bladder?
Inferior thoracic and upper lumbar cord:
- Via hypogastric plexus and nerves to the vesical plexus
What provides PNS innervation to the bladder?
Pelvic splanchnic nerves -> Inferior hypogastric plexus
What does PNS innervation to the bladder do?
Contracts detrusor muscle
Inhibits internal urethral sphincter
Where does lymph from the ureter drain?
Lumbar
Common iliac
External iliac
Internal iliac
Where does lymph from the bladder drain?
Internal iliac
(Some to external iliac superiorly)
(Some from neck to sacral nodes)
Where does lymph from the urethra drain?
Internal iliac Males: - Spongy urethra -> Deep inguinal Females: - Some to sacral nodes
What is the relation of the rectum to the peritoneum?
Upper 1/3 covered by visceral peritoneum
Middle 1/3 has peritoneum on anterior surface
Lower 1/3 is infraperitoneal
What is the course of the rectum?
From S3 (rectosigmoid junction) To tip of coccyx
What forms the 3 lateral flexures in the rectum?
3 internal transverse rectal folds:
- 2 on left
- 1 on right
What supports the rectal ampulla?
Levator ani
Anococcygeal ligament
What is the arterial supply to the rectum?
Superior rectal artery (inf. mesenteric)
Middle rectal artery (int. iliac)
Inferior rectal artery (int. pudendal)
What conveys SNS supply to the rectum?
Lumbar splanchnic nerves
Hypogastric/pelvic plexuses
(Via peri-arterial plexuses)
What conveys PNS supply to the rectum?
Pelvic splanchnic nerves (S2-S4):
- Inf. hypogastric plexus -> Rectal plexuses
What is the lymphatic drainage of the rectum?
Pararectal nodes:
- Inferior mesenteric
- Internal iliac
What is the broad ligament?
Double layer of peritoneum extending from sides of uterus to lateral walls and floor of pelvis
What part of the broad ligament is prolonged laterally over and contains the ovarian vessels?
Suspensory ligament of the ovary
What ligament lies posterosuperiorly between the layers of the broad ligament?
Ligament of the ovary
What ligament lies anteroinferiorly between the layers of the broad ligament?
Round ligament of the uterus
What part of the broad ligament do the uterine tubes lie in anterosuperiorly?
Mesosalpinx
What part of the broad ligament do the ovaries lie in posteriorly?
Mesovarium
What part of the broad ligament lies inferiorly and is the main part?
Mesometrium
What are the ligaments, attached to the cervix, that support the uterus?
Uterosacral (sacrocervical) Transverse cervical (cardinal): - Cervix to obturator fascia (lateral pelvic wall) Pubocervical (pubovesical): - Cervix to pubic symphysis
What is anteversion of the uterus?
Long axis of uterus bent forward on long axis of vagina
What is the angle of anteversion of the uterus?
90 degrees
What is anteflexion of the uterus?
Long axis of uterus bent forward at internal os with long axis of vagina/cervix
What is the angle of anteflexion of the uterus?
170 degrees
What is the arterial supply to the ovaries?
Paired para-aortic branches at L2
Where does the right ovarian vein drain?
IVC
Where does the left ovarian vein drain?
Left renal vein
Where do nerves supplying the ovaries arise?
Aortic plexus
What structures of the female reproductive system drain lymph to the aortic nodes at L2?
Ovaries
Fundus
Uterine tubes
Where does lymph from the isthmus of the uterine tubes drain to?
Superficial inguinal niodes
Where does lymph from the body of the uterus drain?
External iliac nodes (via broad ligament)
Where does lymph from the cervix drain?
Internal iliac nodes
Some to sacral
Where does lymph from the external cervical os drain?
Internal iliac nodes -> Superficial inguinal nodes
What is formed when the vas deferens and the duct from the seminal vesicle join?
Ejaculatory duct
Within what structure does the urethra meet the ejaculatory duct?
Prostate
What are the dimensions of the seminal vesicles?
5cm long
10-15cm long is uncoiled
What do the seminal vesicles secrete?
Liquid component of semen
Fructose
What part of the prostate is related to the neck of the bladder?
Base of prostate
What proportions of the prostate are glandular and fibromuscular?
2/3 glandular
1/3 fibromuscular
What surrounds the prostate?
Fibrous capsule
What is the structure of the anterior surface of the prostate?
Muscular
What is the posterior surface of the bladder related to?
Rectal ampulla
What is the inferolateral surface of the prostate related to?
Levator ani
What does the prostate produce?
Proteolytic enzymes
Acid phosphatase
What structures support the prostate?
Puboprostatic ligament (to pubic symphysis) Levatore prostatae
What is the venous drainage of the prostate?
Deep dorsal vein of penis -> Prostatic venous plexus -> Internal iliac vein
What is the arterial supply to the seminal vesicles?
Branches from:
- Inferior vesical arteries
- Middle rectal arteries
What is the arterial supply to the prostate?
Prostatic branches from:
- Internal iliac arteries
- Inferior vesical arteries
- Internal pudendal arteries
- Middle rectal arteries
What lobe of the prostate often enlarges most? What can this cause?
Middle lobe
Obstruction of internal urethral orifice
How does prostatic enlargement affect urination?
Impedes urination by distorting prostatic urethra
What are the symptoms of prostate enlargement?
Nocturia
Dysuria
Urgency
In what populations is prostatic enlargement most common?
Males older than 50 years
What is the lymphatic drainage of the seminal vesicles?
Upper parts -> External iliac
Lower parts -> Internal iliac
What is the lymphatic drainage of the prostate?
Internal iliac
What is the lymphatic drainage of the male urethra?
Prostatic part -> Internal iliac
Spongy part -> External iliac and deep inguinal (distally)
Membranous/Intermediate part -> External iliac
What is the lymphatic drainage of the testes?
Aortic nodes at root of testicular artery at L2
What is the lymphatic drainage of the skin of the penis and the scrotum?
Superficial inguinal
What structures form the urogenital triangle?
Lines from pubic symphysis to each ischial tuberosity and a line between the ischial tuberosities
What structures form the anal triangle?
Lines from coccyx to each ischial tuberosity and a line between the ischial tuberosities
What are the boundaries of the perineum?
Anteriorly - Pubic symphysis
Anterolaterally - Ischiopubic rami
Laterally - Ischial tuberosities
Posterolaterally - Sacrotuberous ligaments
Posteriorly - Inferiormost sacrum and coccyx
What structures form the anterior boundaries of the ischioanal (rectal) fossa?
Colles’ fascia
Inferior urogenital diaphragm
What structures form the lateral boundaries of the ischioanal (rectal) fossa?
Ischial tuberosity
Obturator internus
What structures form the medial boundaries of the ischioanal (rectal) fossa?
Levator ani
External anal sphincter
What structures form the posterior boundaries of the ischioanal (rectal) fossa?
Gluteus maximus
Sacrotuberous ligament
What structure forms the superior boundary of the ischioanal (rectal) fossa?
Levator ani
What structure forms the inferior boundary of the ischioanal (rectal) fossa?
Skin
What are the contents of the ischioanal fossae?
Branches of pudendal vessels and nerves:
- Inferior rectal nerve
- Inferior rectal artery and vein
Adipose tissue
What is the course of the anal canal?
From superior aspect of pelvic diaphragm
To anus
What parts of the anal canal does the internal anal sphincter surround?
Superior 2/3
What type of muscle is the internal anal sphincter and what nerves innervate it?
Smooth:
- SNS (maintains contraction)
- PNS (allows defaecation)
Where do the anal columns lie?
In the mucous membrane of the internal superior half of the anal canal
What is contained in the anal columns?
Terminal vessels of:
- Superior rectal artery
- Superior rectal vein
What lies at the superior ends of the anal columns?
Anorectal junction
What joins the anal columns at their inferior ends? What are these lying just inferior to?
Anal valves
Lying just inferior to the anal sinuses (secrete mucus to aid defaecation)
What parts of the anal canal does the external anal sphincter surround?
Inferior 2/3
What are the attachments of the external anal sphincter?
Anteriorly - Perineal body
Posteriorly - Anococcygeal ligament
What is the function of the external anal sphincter?
Closes the anus (aided by puborectalis)
What is the innervation to the external anal sphincter?
Inferior rectal branch of pudendal nerve (S2-S4)
What is the pectinate line?
Site of anal membrane in foetus dividing the upper 2/3 (visceral; hindgut-derived) of the anal canal from the lower 1/3 (somatic; proctodeum derived)
What is the blood supply to the anal canal?
Superior rectal artery (above pectinate line)
Inferior rectal artery (below pectinate line)
What is the name of the line that is the true transition to skin from the anal canal?
Anocutaneous line
What is the lymphatic drainage of the anal canal?
Internal iliac (above pectinate line) Superficial inguinal (below pectinate line)
What is the fatty Camper’s fascia of the perineum continuous with?
Ischiorectal fossa (fat) Thigh
What is the Camper’s fascia replaced by in males?
Dartos fascia in the:
- Penis
- Scrotum
What does the Camper’s fascia contribute to in females?
Labia majora
Mons pubis
Where does the membranous Colles’ fascia attach?
Posterior border of urogenital diaphragm (perineal membrane and body) posteriorly
Fascia lata of thigh laterally
What is the membranous Colles’ fascia continuous with in males?
Dartos fascia anteriorly in the:
- Penis
- Scrotum
What does the membranous Colles’ fascia contribute to in females?
Labia majora
What are the boundaries of the urogenital diaphragm?
Superiorly:
- Superior UG fascia (blending with perineal body)
Inferiorly:
- Inferior UG fascia (the perineal membrane)
What is contained between the fascial layers of the urogenital diaphragm?
Deep perineal pouch:
- Sphincter urethrae
- Deep transverse perineal muscles
What do the layers of the urogenital diaphragm do anteriorly?
Fuse and leave a small gap near pubic symphysis
What do the posterior aspects of the layers of the UG diaphragm fuse with?
Each other
Membranous Colles’ superficial fascia
Perineal body
What are the boundaries of the deep perineal pouch by more modern understandings?
Superiorly: - Inferior fascia of pelvic diaphragm Inferiorly: - Perineal membrane Laterally: - Inferior part of the obturator membrane (covering internal aspect of obturator internus)
What are the contents of the deep perineal pouch in both sexes?
Urethra Sphincter urethrae (ext. urethral sphincter) Deep transverse perineal muscles Internal pudendal vessels and branches Ischio-anal fat
What are extra contents of the deep perineal pouch in males?
Membranous urethra
Dorsal nerves of penis (branch of pudendal n.)
Bulbourethral glands
Penile arteries (from int. pudendal a.)
What are extra contents of the deep perineal pouch in females?
Vagina
Dorsal nerves of clitoris (branch of pudendal n.)
What are the boundaries of the superficial perineal pouch?
Superiorly: - Perineal membrane Inferiorly: - Skin (membranous Colles' fascia) Laterally: - Ischiopubic rami
What muscles are contained in the superficial perineal pouch?
Ischiocavernosus
Bulbospongiosus
Superficial transverse perineal
What are the other contents of the superficial perineal pouch?
Urethra Vagina Clitoris Penis Branches of internal pudendal vessels and pudendal nerves
What erectile tissues are contained in the superficial perineal pouch?
Crura
Bulb:
- Of vestibule (females)
- Of penis (males)
What is the perineal body?
A small fibrous structure at the posterior margin of the UG diaphragm. It is a mass in the middle line of the junction between the urogenital and anal triangles
What attaches to the perineal body?
External anal sphincter
Bulbospongiosus
Superficial transverse perineal muscles
What structures in the penis are extensions of the crura?
Corpus cavernosus (x2):
- Paired structures
- Lie posteriorly (ie. when penis erect)
What structure in the penis is an extension of the bulb?
Corpus spongiosum (lies anteriorly)
What arteries run within the corpora cavernosa?
Deep arteries of penis
Where do the dorsal arteries of the penis run?
In the dorsal groove between the corpora cavernosa
Where do the dorsal nerves of the penis run?
Lateral to the dorsal arteries of the penis
What are the branches of the pudendal nerve?
Inferior rectal nerve
Perineal nerve (superficial and deep):
- Posterior scrotal/labial branches
Dorsal nerve of penis/clitoris
What are the root values for the sacral plexus?
L4-S4
What are the root values of the sciatic nerve? Where does it form?
L4-S3 anterior rami
On anterior surface of piriformis
Where does the sciatic nerve leave the pelvis?
Via greater sciatic foramen:
- Inferior to piriformis
- Deep to gluteus maximus
What does the sciatic nerve supply?
Posterior thigh
All leg and foot
What are the root values for the superior gluteal nerve?
L4-S1
What does the superior gluteal nerve run alongside?
Superior gluteal vessels
Where does the superior gluteal nerve leave the pelvis?
Greater sciatic nerve:
- Superior to piriformis
What does the superior gluteal nerve supply?
Gluteus medius
Gluteus minimus
Tensor fascia lata
What are the root values of the inferior gluteal nerve?
L5-S2
What does the inferior gluteal nerve run alongside?
Inferior gluteal vessels
What does the inferior gluteal nerve supply?
Gluteus maximus
What are the root values of the nerve to obturator internus?
L5-S1
What is the course of the nerve to obturator internus?
Leaves pelvis via greater sciatic foramen:
- Inferior to piriformis
Descends posterior to sacrospinous ligament
Enters pelvis via lesser sciatic foramen
What does the nerve to obturator internus supply?
Obturator internus
Superior gemellus
What are the root values of the nerve to piriformis?
Direct S1-S2
What is the course of the nerve to piriformis?
Enters anterior surface of piriformis
What nerves supply the levator ani?
Nerve to levator ani (direct S4) Pudendal nerve (via inf. rectal nerve)
What nerves supply coccygeus?
Direct S4 and S5 branches
What are the root values of the pudendal nerve?
S2-S4
What is the course of the pudendal nerve?
- Leaves pelvis via greater sciatic foramen:
- Between piriformis and coccygeus - Hooks around ischial spine
- Enters pelvis via lesser sciatic foramen
- Runs with internal pudendal vessels anterosuperiorly on lateral wall of ischioanal fossa
- Into perineum
What muscles does the pudendal nerve supply?
Levator ani
External anal and urethral sphincters
Bulbospongiosus
Ischiocavernosus
What are the parts of levator ani?
Iliococcygeus
Pubococcygeus
Puborectalis
Pubovaginalis/Puboprostaticus
Where do the lumbar splanchnic nerves arise from and travel to?
From sympathetic chain
To superior hypogastric plexus
Where do the sacral splanchnic nerves arise from and travel to?
From sympathetic chain
To inferior hypogastric plexus
Where do the pelvic splanchnic nerves travel to?
Inferior hypogastric plexus then to the inferior mesenteric plexus (via superior hypogastric and aortic plexuses)
What effect does the SNS have on defaecation?
Prevents it:
- Reduces movement in rectum
- Contracts internal anal sphincter
What effect does the SNS have on urination?
Prevents it:
- Contracts internal urethral sphincter
- Relaxes detrusor muscle
How does the SNS cause ejaculation?
Contracts:
- Ductus deferens
- Seminal vesicles
What effect does the SNS have on the uterus?
Can contract/relax it (hormonal)
What does the PNS have no effect on?
Seminal vesicles
Ductus deferens
Uterus
How does the PNS cause erection?
Vasodilation
What nerves supply the penis and what type of sensation do they carry?
Dorsal nerve of penis: - Somatic sensory - Sympathetic Cavernous nerves (from prostatic plexus): - Parasympathetic
What nerve supplies the perineal muscles in males?
Perineal branch of the pudendal nerves
What nerves supply give somatic sensory supply to the scrotum?
Anterior scrotal nerve (from ilioinguinal/genitofemoral):
Posterior scrotal nerve (from perineal branch of pudendal)
What nerves supply give somatic sensory supply to the female perineum?
Anterior labial nerve (from ilioinguinal/genitofemoral)
Posterior labial nerve (from perineal branch of pudendal)
What nerve supplies the labia?
Posterior labial nerve
What nerve supplies the orifice of the vagina?
Deep branch of pudendal nerve
What nerve supplies the perineal muscles in females?
Muscular branches of pudendal nerve
What nerve supplies the clitoris and deep perineal muscles in females?
Dorsal nerve of clitoris (from pudendal)
What nerve supplies parasympathetic outflow to the bulb of vestibule and clitoris?
Cavernous nerves (from uterovaginal plexus)
At what vertebral level does the aorta divide?
L4
What are the branches of the anterior division of the internal iliac artery?
Umbilical artery -> Superior vesical arteries
Obturator artery
Inferior vesical/Uterine artery -> Prostatic/Vaginal branches
Middle rectal artery
Inferior gluteal artery
What are the branches of the posterior division of the internal iliac artery and what do they supply?
Iliolumbar artery: - Psoas - Quadratus lumborum Lateral sacral: - Piriformis - Vertebral column Superior gluteal
What are the boundaries of the pelvic inlet?
Anterior: - Pubic crest (and symphysis) Lateral: - Iliopectineal lines Posterior: - Sacral promontory - Ala of sacrum
What are the boundaries of the pelvic outlet?
Anterior: - Pubic arch Lateral: - Ischial tuberosities Posterolateral: - Inferior margin of sacrotuberous ligament Posterior: - Tip of coccyx
What forms the anteroinferior wall of the pelvis?
Pubic bodies
Pubic rami
Pubic symphysis
What forms the lateral walls of the pelvis?
Both hip bones
Obturator membranes and obturator internus muscles
What forms the posterior walls of the pelvis?
Sacrum
Coccyx
Piriformis
What forms the roof of the pelvis?
Pelvic inlet
What forms the floor of the pelvis?
Pelvic diaphragm:
- Levator ani
- Coccygeus
Where does the sacrotuberous ligament originate?
Posterior ilium
Lateral sacrum and coccyx
Where does the sacrotuberous ligament insert?
Ischial tuberosity
Where does the sacrospinous ligament originate?
Lateral sacrum and coccyx
Where does the sacrospinous ligament insert?
Ischial spines
What does the sacrotuberous ligament do?
Creates sciatic foramen
What does the sacrospinous ligament do?
Divides foramen into greater and lesser sciatic foraminae
Where does the inguinal ligament run to and from?
From ASIS
To pubic tubercle
What are the anterior sacroiliac ligaments?
Anterior parts of the fibrous capsules of the SIJs (covers synovial part of SIJ)
What are the posterior sacroiliac ligaments?
Posterior external continuations of the interosseous sacroiliac ligaments (covers fibrous part of SIJ)
What is the function of the posterior sacroiliac ligaments?
Run superolaterally:
- Axial weight on sacrum
- Pulls ilia medially
- Locks the SIJs
What type of cartilage is present at the SIJ?
Sacral - Hyaline
Iliac - Fibrocartilage
What type of cartilage is present at the pubic symphysis?
Fibrocartilage (secondary cartilaginous)
What is the shape of an android pelvis, why and who is it common in?
Heart shaped inlet (prominent sacrum)
Men
What is the ‘normal’ female pelvis with an oval inlet and wide transverse diameter?
Gynecoid
What type of pelvis has a long pelvic inlet (AP > Transverse)?
Anthropoid
What is the uncommon pelvis shape that has a flat, kidney-shaped inlet (transverse»_space; AP)?
Platypelloid
What are the origins and insertions of the iliacus?
Origin = Iliac fossa Insertion = Lesser trochanter of femur
What is the function of iliacus?
Flexes hip
What is the nerve supply to iliacus?
Femoral nerve (L2-L3)
What are the origins of psoas?
T12-L4 bodies and IV discs (superficial)
L1-L5 bodies and IV discs (deep)
What is the insertion of psoas?
Lesser trochanter of femur
What are the functions of psoas?
Flexes hip
Bends trunk laterally (one)
Raises trunk from supine (both)
What is the nerve supply to psoas?
Lumbar plexus direct L2-L4 anterior rami
What is the origin and insertion of the obturator internus?
Origin = Inner surface of obturator internus Insertion = Medial surface of greater trochanter of femur
What is the function of obturator internus?
Lateral rotation of hip
What is the nerve supply to obturator inernus?
Nerve to obturator internus (L5-S1)
What are the origins of piriformis?
Anterior/pelvic surface of sacrum
Sacrotuberous ligament
What is the insertion of piriformis?
Superior border of greater trochanter of femur
What is the function of piriformis?
Lateral rotation of hip
What is the nerve supply to piriformis?
Nerve to piriformis (S1-S2)
What are the origins of coccygeus?
Ischial spine
Sacrospinous ligament
What are the insertions of coccygeus?
Coccyx
Inferior sacrum
What are the functions of coccygeus?
Supports pelvic viscera
Flexes coccyx
What is the nerve supply to coccygeus?
Direct branches from sacral plexus S4-S5
What are the most medial fibres of levator ani?
Puborectalis
What are the four parts of the pubococcygeus?
(Puborectalis)
Puboprostaticus/Pubovaginalis
Puboanalis
Puboperinealis
What is the function of pubococcygeus?
Attach to and support:
- Vagina/Prostate
- Rectum
What is the most lateral part of levator ani?
Iliococcygeus
What are the functions of iliococcygeus?
Support pelvic viscera: - Contracts during coughing Relaxes to allow: - Urination - Defaecation
What is the motor innervation to pubococcygeus?
Pudendal nerve (via inferior rectal nerve) Nerve to levator ani (S4)
What do the most medial fibres of pubococcygeus wrap around and insert into in males?
Wrap around prostate
Insert into perineal body -> Levator prostatae (puboprostaticus)
What do the most medial fibres of pubococcygeus pass around and insert into in females?
Pass around vagina
Insert into perineal body -> Pubovaginalis
What do fibres of puborectalis mix with to form?
External anal sphincter
Form a modified sling
What is the function of puborectalis?
Maintains faecal continence:
- Especially after rectal filling (int. anal sphincter open)
What is the nerve supply to puborectalis?
Pudendal nerve (S2-S4) Nerve to levator ani (S4)
What does iliococcygeus attach to?
Fascia of obturator internus -> Tendinous arch of levator ani
Anococcygeal body/ligament/levator plate
What is more fibrous; pubococcygeus or iliococcygeus?
Iliococcygeus
What is the nerve supply to iliococcygeus?
Pudendal nerve
Nerve to levator ani
Where is the parietal pelvic fascia thickened and what does it form?
Over obturator internus:
- Tendinous arch of pelvis (and levator ani)
What do the anterior extensions of the tendinous arch of the parietal pelvic fascia form?
Puboprostatic ligament (males) Pubovesical ligament (females)
Where do the parietal and visceral pelvic fasciae blend?
As organs pierce pelvic floor
What is the paracolpium?
Lateral extensions of visceral fascia from vagina to tendinous arch
What does the endopelvic fascia act as?
Packing around organs
What does the loose type of endopelvic fascia do?
Fills ‘space’ in pelvis (eg. retropubic and retrorectal spaces)
What is the condensed endopelvic fascia?
Thickenings of fascia
What are the primary condensations of the endopelvic fascia condensed type?
Hypogastric sheaths:
- Along posterolateral pelvic walls