Pelvic viscera and Peritoneum (Interval 5) Flashcards
False/greater pelvis boundaries
Bound by iliac fossa, sacrum above the sacral promotory, and anterior abdominal wall
What muscle does the false pelvis contain?
The iliacus muscle, which sits on the iliac fossa
True/lesser pelvis boundaries
Hipbones, sacrum below the sacral promotory, coccyx
What muscles does the true pelvis contain?
The obturator internus and piriformis muscles
-these muscles form the lateral walls of the lesser pelvis
Pelvic inlet
Separates the greater and lesser pelvis
Oval shaped on F, heart shaped on M
Pelvic outlet and its borders
diamond shaped, subdivided into the anal (pubic symphesis) and urogenital (sacrotuberous ligaments) triangles
Borders:
- inferior aspect of the pubic symphysis
- ischiopubic rami
- ischial tuberosities
- sacrospinous ligaments
- tip of the coccyx
Subpubic angle
made by ischiopubic rami coming together at the pubic symphesis
Perineal body
The central tendon of the perineum
Lies in the midline of a coronal plane between the ischial tuberosities
What lies above the pelvic diaphragm?
bladder, prostate, proximal urethra, uterus, upper vagina, rectum
What is the urogenital hiatus
gap in the pelvic diaphragm where the urethra, vagina and rectum go into the perineum
What muscle makes up the anterior pelvic diaphragm?
Levator ani
What muscles make up the levator ani and what are their functions
1a. Pubococcygeus muscle
- encircles the vagina and prostate
1b. Puborectalis muscle
- bounds the urogenital hiatus and forms part of the external anal sphincter
- Iliococcygeus muscle
- forms the posterior third of the pelvic diaphragm
- not much bone attachment because the obturator internus blocks it - “ischio” coccygeus
- forms the posterior third of the pelvic diaphragm
What fascia covers the obturator internus muscle?
The tendinous arch which is a thickening of the fascia covering the obturator internus msucle. The iliococcygeus muscle arises mostly from the tendinous arch
Which spinal nerves have rami that innervate the pelvic diaphragm muscles?
Branches of the pudendal nerve (S2,3,4) innervate the skeletal muscle of the pelvic diaphragm
What is the Ischioanal fossa?
Encloses the pelvic diaphragm. Is filled with fat and connective tissue
What goes through the ischioanal fossa?
The pudendal nerve and the internal pudendal artery and vein course in the lateral wall of the ischioanal fossa through the pudendal canal
What forms the pudendal canal?
The fascia covering the obturator internus muscle
What is the coccygeus muscle
It attaches laterally to the ischial spine and sacrospinous ligament and medially to the coccyx and sacrum
The horseshoe-shaped indent where the ilium, ischeium and pubis fuse
Acetabulum
What is the smallest dimension in the pelvic inlet?
(true) obstetric conjugate (sacral promotory to the midpoint of the symphysis)
What are the three conjugates from the sacral promotory to the pubic sympthesis?
- Obstetric/true conjugate
- Diagonal conjugate
- Anatomical conjugate
What sphincter does the pelvic diaphragm contain?
External anal sphincter
What sphincter does the urogenital diaphragm contain?
Sphincter urethrae
How can we measure the size of the pelvic outlet?
measure the distance between the ischial tuberosities or the size of the subpubic angle
Is the subpubic angle larger for males or females?
Females: 90 degrees
Males: 60 degrees
What is the smallest dimention of the lesser pelvis?
The distance between the ischial spines
Obturator Canal
The obturator foramen is usually covered by obturatur internus muscle. This is a small canal nn the obturatur internus muscle through which the obturator nerve, artery and vein go through
Pudendal nerves where they come from and what they go through
S2-S4, collection of ventral rami that innervate skeletal muscle an sphincter in both pelvic and urogenital diaphragms
Courses in the lateral wall of the ischioanal fossa through the pudendal canal which is formed by the fascia covering the obturator internus muscle
Urethral sphincters male vs female
Males:
- internal urethral sphincter to stop backflow of semen into the bladder-smooth muscle. Just below the prostate
- external urethral sphincter in UG diaphragm-skeletal muscle
Females:
Just have #2
Trigone
Triangle in the bladder made from the ureteric openings and the descent of the urethra
What are the pouches of the peritoneum and what is their clinical significance?
Males:
1. Retrovesical pouch between the posterior bladder and anterior rectum
Females:
- Retrouterine pouch (of Douglas) drapes between the uterus and rectum
- Vesicouterine pouch between the posterior bladder and anterior uterus
The ‘recto’ pouches are the lowest points of the pelvis and thus the points where fluid is most likely to collect
Water under the bridge
Males:
-ureter goes under the ductus deferens
Females:
-ureter goes under the uterine artery
Urogenital diaphragm
Very thin plane of skeletal muscle. Contains the spincter urethrae. Attaches to the external genitalia.
Perineum
- Everything below the pelvic diaphragm
- Contains the urogenital diaphragm and the roots of the external genitalia
Deep perineal pouch
- Found between the superior and inferior fascial layers of the UG diaphragm
- Males: contains membranous part of the urethra and the bulbourethral glands whose ducts open into the penile urethra
- Females: contains the urethra and the vagina
Superficial perineal pouch
Contains the crura and bulbs of the penis and clitoris, which consist of erectile tissue
Crura
2 of them which are attached to the ischiopubic rami and the perineal membrane and continue as the corpora cavernosa into the penis and clitoris
Bulb male vs female
Male: bulb of the penis lies in the midline, is attached to the perineal membrane and contains the penile urethra
Female: bulb of the vestibule are situated in the wall of the vestibule with the greater vestibular glands. Join at the base of the clitoris
What muscles cover the crura?
Ischiocavernosus muscles (skeletal, help maintain erection)
What muscles cover the bulbs?
The bulbospongiosus muscles (skeletal, help maintain erection). Also contract to eject fluid in males during ejaculation and urine during micturition
Name the muscles of the penis and where they came from
Bulb–>Corpus spongiosum
- situated on the ventral aspect of the penis
- surrounds the penile urethra and forms the glans penis
Crura–>Corpora cavernosa
- two of them
- situated in the dorsal aspect of the penis
What encloses the 3 erectile bodies of the penis?
3 bodies=corpus spongiosum and the 2 corpora cavernosa
The deep penil, or buck’s fascia, encloses them, the deep dorsal vein, the dorsal nerves, and the dorsal arteries of the penis
List and describe the external genitalia of the female
- Labia majora
- contain connective tissue and fat and are the homologues of the scrotum - Labia minora
- are in the lateral walls of the vestibule - Vestibule
- chamber into which the urethra and vagina open after passing through the UG diaphragm
What is the prostate’s homolog?
The paraurethral/Skene’s glands. These lubricate the urethra and the vestibule
Name the muscles of the clitoris and where they come from
The clitoris consists of the 2 corpora cavernosa, which form both the body and the glans of the clitoris
Ductus Deferens
- Arise from the epididymis adjacent to the testis
- Transverse the inguinal canal
- Transports sperm produced int he seminiferous tubules of the testies
Seminal Vesicles
- Situated lateral to the ductus deferens ont he posterolateral aspect of the bladder
- Secrete nutrition for seminal fluid
Ejaculatory Duct
- Formed when ductus deferens join with a duct of the seminal vesicles just baove the prostate
- Opens onto the surface of the seminal colliculus in the posterior wall of the prostatic urethra
Prostate zones and their tissue types
Periurethral
- Transition zone
- BPH
Peripheral zone
- glandular tissue
- covers the posterior and lateral aspects of the prostate gland (palpated by rectal exam)
- usually where prostate cancer is
Central Zone
-surrounds the ejaculatory ducts
Prostate location
Below the bladder, posterior to the pubic symphysis, anterior to the rectum
- seminal vesicles lie between the prostate and the bladder
- each seminal vesicle joins its corresponding ductus deferens to form the ejaculatory duct before entering the prostate
Describe the innervation of the pelvis
T11-L2: Lumbar splanchnic nerves and superior hypogastric plexus (parasympathetic)
S2,3,4: Pelvic splanchnic nerves (parasympathetic) and pudendal nerves (sympathetic)
Perineal nerve: dorsal nerve of the clitoris/penis
Sciatic nerve
Inferior rectal nerve
Neurological ‘sex’
- Erection-pelvic splanchincs
- dilates vessels in erectile tissues - Secretion-pelvic splanchnics
- increases secretion production of prostate, seminal and lubricating glands - Emission-lumbar splanchnics
- contract smooth muscle in ductus deferens and glands as well as urethral and anal sphincters - Climax/Ejaculation-pudendal
- relax sphincter urethrae and bulbospongiosus msucle
Uterus
- Between the bladder and the rectum
- Smooth muscle
- Fundus, body, isthmus, cervix
Fornix
Where the vagina encircles the uterus
What is the broad ligament
The broad ligament is a fold of peritoneum that forms a mesentery suspending the uterine tubes, the ovaries, and most of the uterus
What are the parts of the broad ligament?
- Mesometrium
- adjacent to the uterus - Mesosalpinx
- suspends the uterine tubes - Mesovarium
- suspends the ovaries
What are the ligaments in the broad ligament?
- Cardinal ligament
- carries arteries to the cervix and vagina including the uterine artery and vein - Proper ovarian ligament
- contains nothing - Suspensory ligament
- In the mesovarium
- Contains ovary blood supply
What is in the round ligament of the uterus?
The round ligament of the uterus goes into the inguinal canal and contains the artery of sampson
Branches of the internal iliac artery that supply the pelvic viscera
- Umbilical artery
- Uterine artery
- usually a branch of umbilical artery, passes over ureter - Artery of ductus deferens
- Vaginal artery
- inferior vesical artery
- Middle rectal artery
Branches of the internal iliac artery that supply the perineal structures
- Internal pudendal
- runs through greater sciatic foramen, crosses ischial spine, passes through lesser sciatic foramen
- Inferior rectal artery
- Perineal branch
- Artery to the bulb and deep artery of the penis and clitoris
- Dorsal artery of the penis and clitoris
Branches of the internal iliac artery that supply the pelvic walls
- Iliolumbar artery
- Lateral sacral artery
Lower limb branches come later including
1. superior gluteal, inferior gluteal, obturator
