Module 10 - Pelvis Flashcards
Bony pelvis (pelvic girdle) description
“Ring of bone” formed by R/L hip bones, sacrum, coccyx
Function of pelvic girdle
Supports abdomen
Provides dynamic link between vertebral column and lower limbs
Iliopectineal line (pelvic brim)
Divides the pelvis into pelvic major (false) and pelvic minor (true)
Hip bones
Ilium
Ischium
Pubis
Landmarks of Ilium
Body, iliac crest, iliac tubercle ASIS, AIIS, PSIS, PIIS Auricular surface Arcuate line Iliopectineal line Greater sciatic notch
Landmarks of Ischium
Body Ischial spine Lesser sciatic notch Ischial tuberosity Ramus
Landmarks of Pubis
Superior and inferior pubic rami Pubic symphysis, crest, tubercle Pectin pubis (pectineal line) Iliopectineal line Obturator canal
Landmarks of Sacrum
Base (superior portion) Apex (inferior portion) Median and lateral sacral crests Ala Promontory Sacral cornu, hiatus
Pelvis apertures
Superior (pelvic inlet/brim) - sacrum, ilium, pubis
Inferior (pelvic outlet) - diamond shaped
Superior pelvic aperture (inlet) - posterior, lateral, anterior boundaries
Posterior: promontory and anterior border of ala of sacrum (sacrum)
Lateral: ilipectineal line (illium)
Anterior: pubic symphysis, pectin pubis, pubic crest (pubic)
Pelvis major
“False” pelvis
Region above iliopectineal line
Pelvis minor
“True” pelvis
Region below iliopectineal line
Inferior pelvic aperture (outlet) - posterior, lateral, anterior boundaries
Posterior: sacrum and coccyx
Lateral: ischial tuberosities, sacrotuberous ligaments
Anterior: pubic symphysis, arcuate ligament, rami of pubis and ischium
*Pelvic “floor”
Pelvis major contains:
Ileum of small intestine
Sigmoid colon
Pelvis major boundaries
Abdominal wall, iliac fossae, L5/S1
Pelvis minor contains:
Urinary and reproductive organs
Pelvis minor boundaries
Pelvic surfaces of hip bones, sacrum and coccyx
Acetabulum is formed by:
Junction of 3 hip bones (ischium, ilium, pubis)
Acetabulum features
Acetabular notch, lunate, margin
T/F: Acetabulum is round in females
FALSE, it is round in males
Obturator foramen is formed by:
Rami of pubis and ischium
What passes through obturator foramen?
Obturator nerve, blood vessels
Joints of the pelvis:
Sacroiliac
Pubic symphysis
Sacroiliac joint type
Synovial, irregular plane with “ear shaped” auricular surfaces
Sacroiliac joint ligaments
Posterior, interosseous, anterior SI ligaments
Movements at the sacroiliac joint
Slight gliding and rotation
*Research agrees that there is movement, but disagrees on magnitude/direction
Pubic symphysis joint type
Fibrocartilaginous
T/F: Interpubic disc of pubic symphysis is thicker in males
FALSE, it is thicker in females
Ligaments of the pubic symphysis
Superior pubic - connects superior pubic bodies, R/L tubercles
Inferior pubic - arcuate ligament
Vertebropelvic ligaments
Iliolumbar
Sacrotuberous
Sacrospinous
Ligaments of sacroiliac joint
Iliolumbar ligament
L4/5 to iliac crest
Sacrotuberous ligament
Lateral sacrum/coccyx/PIIS to ischial tuberosity
Sacrospinous ligament
Caudal border of sacrum to ischial spine
Ligaments of sacroiliac joint
Posterior and interosseous = very strong
Anterior = thin
Anterior pelvic wall
Bodies and rami of pubic bones, obturator internus muscle/fascia, pubic symphysis
Lateral pelvic wall
Obturator internus muscle, obturator nerves and vessels, branches of internal iliac vessels
Obturator internus attachments
Ilium/ischium + greater trochanter femur
Obturator internus innervation
Nerve to obturator internus (L5-S2)
Obturator internus actions
External rotation of femur
Stabilize head of femur
Piriformis attachments
Sacrum/greater sciatic notch + greater trochanter femur
Piriformis innervation
Ventral rami of S1-S2
Piriformis actions
External rotation, abduction of femur
Stabilize head of femur
Posterior pelvic wall
Sacrum and adjacent parts of ilium
Sacroiliac joints and their ligaments
Piriformis muscle
Sacral plexus and internal iliac vessels
Piriformis syndrome
Myofascial trigger points
Potential for entrapment of sciatic nerve
Pelvic diaphragm consists of:
Levator ani and coccygeus muscles
Levator ani function
Supports pelvic viscera
Resists intra-abdominal pressure
Levator ani parts
Puborectalis
Pubococcygeus
Iliococcygeus
Puborectalis
U-shaped, lasso around anorectal junction
Pubococcygeus
Main part of levator ani
Levator ani attachments
Body of pubis/obturator membrane/ischial spine + coccyx/walls of prostate or vagina/rectum/anal canal
Levator ani actions
- Raise pelvic floor (assisting in compression of abdominal/pelvic contents)
- Voluntary control of urination, fecal incontinence
Pelvic floor consists of:
Levator ani
Ischiococcygeus (small portion of pelvic floor)
Ischiococcygeus attachments
Ischial spine to coccyx and lower sacrum
Ischiococcygeus actions
Assists levator ani in supporting pelvic viscera, flex coccyx
Blood vessels of pelvis
Common iliac External iliac Internal iliac Superior rectal Median sacral Gonadal
Common iliac artery bifurcates at:
L4
External iliac artery passes through ______ only
False pelvis
External iliac artery runs along _____
Medial border of psoas
Branches of external iliac artery:
Inferior epigastric
Deep circumflex
External iliac artery exits _____ deep to _____ and becomes ______
False pelvis
Inguinal ligament
Femoral artery
Internal iliac artery descends in pelvis to ______ where it divides into _____
Greater sciatic foramen
Anterior and posterior divisions
Posterior division of internal iliac artery and what they supply
- Superior gluteal: piriformis, 3 glutes, TFL
- Iliolumbar: psoas, iliacus, quadratus lumborum
- Lateral sacral: piriformis, sacral canal, erector spinae
Anterior division (visceral branches) of internal iliac artery and what they supply
- Umbilical: superior bladder
- Superior vesical: superior bladder, pelvic part of ureter
- Inferior vesical (male): inferior bladder, ductus deferens, prostate
- Vaginal: inferior bladder, vagina
- Uterine: uterus, ligament of uterus, vagina
- Middle rectal: seminal vesicles, lower rectum
- Internal pudendal: perineum
- Obturator: pelvic muscles, femur head, medial thigh muscles
- Inferior gluteal: pelvic diaphragm, piriformis, quadratus femoris, upper hamstrings, glut max, sciatic nerve
Superior rectal artery supplies:
Upper portion of rectum
*Branch of inferior mesenteric artery
Median sacral artery supplies:
Lower lumbar vertebrae, sacrum, coccyx
*Branch of abdominal aorta
Gonadal arteries
Ovarian (female)
Testicular (male)
*Branches of abdominal aorta
Nerves of the pelvic region
Lumbar plexus
Sacral plexus
Lumbar plexus is formed by:
Ventral primary rami of L1-L4
Roots of the lumbar plexus split into _____ within the _____ muscle
Anterior and posterior divisions
Psoas
Terminal branches of the lumbar plexus
Iliohypogastric Ilioinguinal Lateral femoral cutaneous Femoral Obturator Genitofemoral Branch to lumbosacral trunk
Ilioinguinal and iliohypogastric nerves
- L1
- Pass inferolateral and anterior to quadratus lumborum
- Supply skin to suprapubic and inguinal regions
- Motor supply to abdominals
Lateral femoral cutaneous nerve
- L2, L3
- Cutaneous supply to anterior and lateral thigh
Femoral nerve
- L2 thru L4
- Posterior divisions
- Supply hip flexors and extensors of knee
- Lateral to BV as it enters thigh deep to inguinal ligament
Obturator nerve
- L2 thru L4
- Anterior divisions
- Supply adductors of thigh
Genitofemoral nerve
- L1, L2
- Pierces anterior surface of psoas
- Divides into genital and femoral branches (cutaneous anterior thigh)
Branch to lumbosacral trunk
- L4
- Contributes to formation of sacral plexus
Sacral plexus is formed by:
Lumbosacral trunk (L4, L5) and ventral primary rami of S1-S4
Sacral plexus runs ______ into _____ region through the ______
Inferolaterally
Gluteal
Greater sciatic foramen
Sacral plexus supplies:
- Musculature and skin of buttocks
- Posterior compartment of thigh
- Entire leg and foot below the knee
Anterior division branches of sacral plexus
Nerve to quadratus femoris
Nerve to obturator internus
Pudendal
Nerves to levator ani and coccygeus
Posterior division branches of sacral plexus
Superior gluteal
Inferior gluteal
Perforating cutaneous nerve
Nerve to piriformis
Sacral plexus branches from both anterior and posterior divisions
Sciatic nerve
Posterior femoral cutaneous
Superior gluteal nerve
- L4, L5, S1
- Passes out of greater sciatic foramen superior to piriformis
- Supplies glut minimus, glut medius, TFL
Inferior gluteal nerve
- L5, S1, S2
- Passes inferior to piriformis
- Supplies glut max
Perforating cutaneous nerve
- S2, S3
- Skin of medial buttock
Nerve to piriformis
- S1, S2
- Supplies piriformis
Nerve to quadratus femoris
- L4, L5, S1
- Supplies quadratus femoris AND inferior gemellus
Nerve to obturator internus
- L5, S1, S2
- Supplies obturator internus AND superior gemellus
Pudendal nerve
- S2 thru S4
- Major nerve of perineum (supplies muscles and skin)
Nerves to levator ani and coccygeus
- S3, S4
- Supplies levator ani and coccygeus
Sciatic nerve
- L4, S3
- Splits into common fibular and tibial nerves
Common fibular nerve
- L4 thru S2
- Branch of sciatic
- Posterior divisions
Tibial nerve
- L4 thru S3
- Branch of sciatic
- Anterior divisions
Posterior femoral cutaneous nerve
- S1 thru S3
- Buttock, upper posterior and medial thigh
Function of urinary bladder
Temporary storage of urine
Location of urinary bladder
True pelvis (below brim) *Will extend above brim when full
Anterior surface of urinary bladder
Located posterior to pubic symphysis
Superior surface of urinary bladder
Males: located inferior to peritoneum of abdom cavity
Females: located inferior to uterus and vesicouterine pouch
Vesicouterine pouch
Females
Peritoneal space between bladder and uterus
Posterior surface of urinary bladder
Males: located anterior to rectovesical pouch, rectum, seminal vesicles, ampulla of ductus deferens
Females: located anterior to vagina
Rectovesical pouch
Males
Peritoneal space between bladder and rectum
Landmarks of urinary bladder
Apex (anterior portion)
Fundus (posterior portion)
Neck (inferior portion leading to urethra)
Trigone (posterior wall)
In males, the _____ is located inferior to neck of urinary bladder
Prostate gland
In females, the _____ is located inferior to neck of urinary bladder
Urogenital diaphragm
Trigone of bladder
- “Triangle” formed by 2 openings of ureters and opening or urethra
- Specialized smooth muscle of bladder wall
Muscles of bladder
Detrusor
Internal urethral sphincter
External urethral sphincter
Detrusor muscle
Smooth muscle that lines walls of bladder
Internal urethral sphincter
Smooth muscle that forms a sphincter at junction of bladder and urethra
External urethral sphincter
SKELETAL muscle that forms a sphincter around urethra as it passes through urogenital diaphragm
Micturation
Reflex action that can be controlled voluntarily via higher CNS influence
At “rest” when bladder is not full:
- Sympathetic nerves cause internal urethral sphincter to contract
- Detrusor wall is relaxed
- External urethral sphincter is contracted
At _____ mL, you begin to be slightly aware of bladder
150
At more than ____ mL, increased stimulus of stretch receptors in bladder wall
300-400
At _____ mL, urgency!
600+
Distension of bladder stimulates:
- Parasymp nerves (S2-4) to contract detrusor
- Higher CNS centers can voluntarily inhibit this reflex
- Parasymp nerves (S2-4) to relax internal urethral sphincter
- Voluntary relaxation of external urethral sphincter
Male reproductive organs
Testes Epididymis Ductus deferens Seminal vesicle Prostate gland Bulbourethral (Cowper's) gland External genitalia (testes, scrotum, penis)
Female reproductive organs
Ovaries Uterine tube Uterus Vagina External genitalia (vestibule, clitoris, labia majora)
Testes develop ____ and descend into _____
Retroperitoneally
Scrotum
Testes function
Produce sperm and sex hormones
Sperm produced in:
Seminiferous tubules of testes
Epididymis structure and functions
- Convoluted duct (head, body, tail)
- Storage and maturation of sperm (head)
- Propulsion of sperm into ductus deferens
Ductus deferens arises from _____, travels up through ____ and _____
Epididymis
Spermatic cord and Inguinal canal
Ductus deferens enters pelvis via ____
Deep inguinal ring
lateral to inferior epigastric artery
Ductus deferens ends as the:
Ampulla of ductus deferens
Ejaculatory duct =
Ductus deferens merged with seminal vesicle
Ejaculatory duct passes through ____ and enters ____
Prostate
Prostatic urethra
____ provides nutrition for sperm
Fructose
Seminal vesicle location
Along posterolateral portion of bladder just lateral to ductus deferens
Seminal vesicle functions
- Produces seminal fluid (contains fructose and choline)
* Fructose is not produced anywhere else in body so forensic science uses it to determine if sexual assault has occurred
Florence’s test
Determine presence of semen via choline crystals in sexual assault cases
Prostate gland location
Base of urinary bladder
Surrounds urethra
Prostate gland functions
- Produces fluid that combines with sperm and other fluids to form semen (seminal fluid)
- Secretes PSA and acid phosphatase
Prostate gland lobes
- Anterior: isthmus, located anterior to urethra, NO glandular tissue
- Middle: located between urethra and ejaculatory ducts, physically constricts urethra and obstructs urine flow
- Posterior: posterior to urethra and inferior to ejaculatory duct
- R/L Lateral: major portion of gland on each side of urethra
Which lobe(s) of the prostate is prone to BPH?
Middle and lateral lobes
Which lobe of the prostate is easily palpated upon digital exam?
Posterior
Which lobe of the prostate does cancer typically begin?
Posterior
Venous return of the prostate
2 pathways
Prostatic venous plexus drains into:
1. Internal iliac > IVC
2. Vertebral venous plexus > cranial dural sinuses
Where does prostate cancer usually metastasize to?
Heart/lungs and vertebral column/brain
Why does prostate cancer metastasize to heart/lungs and vertebral column/brain?
Two pathways of venous return from the prostate:
- Internal iliac > IVC > heart/lungs
- Vertebral venous plexus > cranial dural sinuses
Bulbourethral (Cowper’s) gland description/location/function
- 2 small glands located posterior to membranous urethra
- Secrete mucus-like secretion into urethra
Scrotum
Cutaneous pouch that does not have any fat
Why doesn’t the scrotum have any fat?
Allows for maintaining lower temperature
Scrotum contains:
Testes and epididymis
Penis structures
Body
Root
Head (glans penis)
Urethra
Penis body is formed by:
3 columns:
- one Corpus Spongiosum
- two Corpus Cavernosa
Penis root consists of:
2 crura
Bulb of penis
Glans penis is formed by:
Terminal portion of corpus spongiosum
Male urethra passes through:
Corpus spongiosum
Prostatic urethra description
Surrounded by prostate
Urethral crest located on posterior wall
Ejaculatory and prostatic ducts enter urethra here
Seminal colliculus
- Oval raised portion of urethral crest of prostatic urethra
- Contains openings of ejaculatory, prostatic ducts, prostatic utricle
Prostatic utricle
- Located in seminal colliculus of urethral crest of prostatic urethra
- Blind outpocket that is analogous to vagina and uterus in female
Male urethra passes through ___ and consists of:
Corpus spongiosum
Prostatic, membranous, spongy (cavernous) urethra
Prostatic utricle
- Located in seminal colliculus of urethral crest of prostatic urethra
- Blind outpocket that is analogous to vagina and uterus in female
Membranous urethra
External urethral sphincter
Spongy (cavernous) urethra
- Passes through length of penis within corpus spongiosum
- Duct of bulbourethral gland enters here
Ovaries location
Lateral to infundibulum of uterine tube
Ovaries contain:
Ovarian follicles
Ovaries function
Secrete estrogen and progesterone
Ovulation process
- Oocyte release from ovary into peritoneal cavity near ostium of infundibulum
- Fimbriae of infundibulum trap oocyte and bring it into uterine tube
Uterine tube parts
Intramural portion - lies within uterine wall
Isthmus - thick muscular wall, extends from uterine wall to ampulla
Ampulla - dilated, longest segment
Infundibulum - distal segment, terminates in fimbriae, contains abdominal ostium which opens into peritoneal cavity
Which part is the longest segment of the uterine tube?
Ampulla
Which part of the uterine tube ends in fimbriae?
Infundibulum
Which part of the uterine tube is most common site for fertilization?
Ampulla
Which part of uterine tube is most common site for ectopic implantation?
Ampulla
Uterus location
Between rectum and bladder
Uterus function
Facilitates movement of sperm from cervix
Provides safe, nourishing environment for fetus
Contracts to push fetus and placenta out during birth
Divisions of the uterus
Body - fundus, isthmus
Cervix (neck) - narrow cylinder that enters and projects into vagina; consists of internal os, cervical canal, external os
T/F: Body is the upper 2/3 of uterus
True
Fundus of uterus
Rounded portion of uterus located above uterine tubes
Isthmus of uterus
Narrow region of body of uterus that connects to cervix
External os
Opening into vagina
Various positions of uterus
Anteverted (50%)
Retroverted (25%)
Midposition (25%)
Wall of the uterus contains 3 layers:
Perimetrium (outer serous coat)
Myometrium (middle muscular coat)
Endometrium (inner mucous coat)
Structures that provide support to uterus
Pelvic & urogenital diaphragms Round ligament of uterus Transverse cervical ligament Uterosacral ligament Pubocervical ligament Broad ligament
Broad ligament of uterus
- Double fold of peritoneum that extends from uterus to pelvic wall
- Supports ovary, uterine tubes, uterus
Broad ligament of uterus contains:
- Uterine tube, round ligament, many duct remnants of embryo
- Ovarian artery, vein, nerve
- Uterine artery, vein, nerve
What is the MC gynecological malignancy?
Cervical cancer
Uterine fibrinoids
Benign neoplasms of smooth muscle origin
Can cause infertility if it blocks uterine tubes
Potential locations of uterine fibrinoids
Within myometrium Beneath endometrium (expand inward into uterine cavity) Along external serosal layer (expand outward into peritoneal cavity)
Vagina
Tube that connects uterus to vestibule
Dilates/extends width of pelvic outlet during childbirth
Fornix (superior portion) encircles cervix of uterus
Three regions of vaginal fornix
Anterior - can palpate bladder on digital exam
Lateral
Posterior - can palpate rectum on digital exam
What is the site for culdocentesis?
Posterior fornix of vagina
Culdocentesis of vagina
Insert needle to collect fluid sample
Assess pelvic conditions (PID, ectopic preg) OR to collect oocytes for in vitro fertilization
Vestibule
Region in which the vagina and urethra open into after passing through urogenital diaphragm
Clitoris
Body and glans formed from two corpus cavernosa
Located anterior to opening of urethra
Female urethra descends ____ distance from ____ to _____
Short
Bladder
Urethral opening
Labia majora
Analogous to male scrotum
Contains connective tissue layers
Round ligament passes through inguinal canal and ends blindly in labia majora
Where does the round ligament of the ovary end?
Labia majora
Labia minora
Medial to labia majora
Form lateral walls of vestibule
Perineum description
Diamond shaped space that is part of pelvic outlet
Perineum boundaries (anterior, anterolateral, lateral, posterolateral, posterior)
Anterior: pubic symphysis Anterolateral: ischiopubic rami Lateral: ischial tuberosities Posterolateral: sacrotuberous ligaments Posterior: Coccyx
Perineum can be divided into 2 smaller triangles:
Urogenital
Anal
Vertical boundaries of perineum
Roof = skin/fascia Floor = pelvic diaphragm
Urogenital triangle
Superficial perineal space
Deep perineal space
Superficial perineal space of urogenital triangle
- Between Colle’s fascia and inferior fascia of urogenital diaphragm (perineal membrane)
- Muscles: ischiocavernosus, bulbospongiosus, superficial transverse perineal
Deep perineal space of urogenital triangle
- Between perineal membrane and superior fascia of urogenital diaphragm
- Muscles: deep transverse perineal, sphincter urethrae, sphincter urethrovaginalis (female), compressor urethrae (female)
Anal triangle muscles
Obturator internus
Levator ani
Sphincter ani externus
Coccygeus
Rectum location, function, venous return
- Extends from sigmoid colon to anal canal
- Dilated portion known as ampulla for feces storage
- Located just superior to pelvic diaphragm
- Inferior and middle rectal veins connect to IVC
- Superior rectal vein connects to portal venous system
What separates the anal canal from rectum?
Pelvic diaphragm
Anal canal begins at ____ and ends at ____
Pelvic diaphragm
Anus
Anal canal is divided into these 2 portions:
Visceral (upper 2/3)
Somatic (lower 1/3)
What divides the visceral and somatic portions of anal canal?
Pectinate line
Visceral portion of anal canal
Internal anal sphincter (smooth muscle)
Internal hemorrhoids occur her
Venous return is mainly through portal system
Somatic portion of anal canal
Externa anal sphincter
External hemorrhoids occur here
Venous return is mostly through caval system (IVC)