regional anatomy of pelvis Flashcards
components of the Os Coxa
Ilium, ischium and pubis
know the following structures: ilium, ischium, pubis, acetabulum, anterior superior iliac spine, iliac crest, auricular surface, ischial spine, ischial tuberosity, ischiopubic ramus, pubic symphysis, obturator foramen
ilium: superior. Ischium: posterior. Pubis: anterior.
Know the following ligaments: sacrotuberous, sacrospinous, obturator membrane
sacrotuberous: From ischial tuberosity to sacrum/coccyx. Sacrospinous: From ischial spine to sacrum/coccyx, deep to the sacrotuberous lig. Obturator: covers most of obturator foramen
where do the following nerves exit? Pudendal, obturator
pudendal n: deep to the sacrotuberous ligament and superficial to the sacrospinous ligament. Obturator: Through the obturator foramen, superior to the obturator membrane.
where do the following vessels exit? Internal pudendal a and v, obturator a and v.
internal pudendal a and v: deep to the sacrotuberous ligament and superficial to sacrospinous ligament. Obturator a and v: Through the obturator foramen, superior to the obturator membrane.
- Describe the weak areas of the pelvic bones that are the most commonly fractured
- pubic rami: risk during AP compression 2. acetabulum: risk during fall on feet from a tall height which drives head of femur into acetabulum. Also lateral compression of pelvis
clinical implications of the pubo-obturator fracture
high risk of complication due to damage to urinary bladder and urethra which may be torn or ruptured
straddle injury
(fracture of all 4 pubic rami) causes serious loss of pelvic stability
pelvic inlet vs outlet
Inlet: superior border of pelvis. Outlet: bounded by coccyx, inferior pubis and ischial tuberosities. Funnel shaped. The true pelvis lies between the pelvic inlet and outlet
true vs false pelvis
True: btw pelvic inlet and outlet. Contains pelvic viscera of obstetrical and gynecological importance and its contents are supported inferiorly by pelvic diaphragm. False: bounded by iliac blades and S1 vertebrae, anterolateral abdominal wall. superior to pelvic inlet. contains abdominal viscera
what/where is the pelvic diaphragm and what does it do
muscles at the inferior aspect of the lesser/true pelvis. Separates true pelvis from perineum (below). Maintains tonic contraction most of the time to support pelvic viscera and maintain urinary/fecal continence. Actively contracted during forced expiration, coughing, sneezing, vomiting
muscles of the pelvic diaphragm
Coccygeus (posterior- from sacrum, coccyx and sacrospinous ligament to ischial spine), and levator ani (surrounds urogenital hiatus and anus, spanning from pubis to ischial spine, also attaching to tendinous arch of obturator fascia)
List the muscles of levator ani
puborectalis, pubococcygeus, iliococcygeus. All 3 meet at midline raphe and anococcygeal ligament
grading of pelvic floor injuries during childbirth
Grade 1 superficial tissues, Grade 2 involves some tearing of muscles, Grade 3 tear extends to anal sphincter
Most common inuries during child birth
In Grade 2+ tears, Pubococcygeus and puborectalis parts of Levator Ani are most commonly torn, along with more superficial tissues of perineum, b/c more medially positioned
-Follow the trajectory of sperm from production (testes) to ejaculation (navicular fossa, head of penis)
testes > epidiymis > ductus deferens > seminal glands > ejaculatory duct > prostate > bulbourethral glands > urethra
parasympathetic vs sympathetic innervation of penile structures
PSNS: penile erection (S2-S4). SNS: ejaculation- trigger contractions of ductus deferens, contraction/secretion from seminal glands and prostate (L1-L2)
describe descnt of the testes
developing testes are extraperitoneal in superior lumbar region of posterior abdomen and are connected to anterolateral wall (deep inguinal ring area) by gubernaculum. At 28 weeks, the processus vaginalis (a peritoneal diverticulum) traverses the inguinal canal to the developing scrotum carrying layers of muscle and fascia with it. The testes follow the processus through the inguinal canal and into the scrotum. During this migration through Canal, the testes, its duct, vessels and nerves become ensheathed in layers from the abdominal wall
developing testes are extraperitoneal in superior lumbar region of posterior abdomen and are connected to anterolateral wall (deep inguinal ring area) by gubernaculum. At 28 weeks, the processus vaginalis (a peritoneal diverticulum) traverses the inguinal canal to the developing scrotum carrying layers of muscle and fascia with it. The testes follow the processus through the inguinal canal and into the scrotum. During this migration through Canal, the testes, its duct, vessels and nerves become ensheathed in layers from the abdominal wall
developing testes are extraperitoneal in superior lumbar region of posterior abdomen and are connected to anterolateral wall (deep inguinal ring area) by gubernaculum. At 28 weeks, the processus vaginalis (a peritoneal diverticulum) traverses the inguinal canal to the developing scrotum carrying layers of muscle and fascia with it. The testes follow the processus through the inguinal canal and into the scrotum. During this migration through Canal, the testes, its duct, vessels and nerves become ensheathed in layers from the abdominal wall
developing testes are extraperitoneal in superior lumbar region of posterior abdomen and are connected to anterolateral wall (deep inguinal ring area) by gubernaculum. At 28 weeks, the processus vaginalis (a peritoneal diverticulum) traverses the inguinal canal to the developing scrotum carrying layers of muscle and fascia with it. The testes follow the processus through the inguinal canal and into the scrotum. During this migration through Canal, the testes, its duct, vessels and nerves become ensheathed in layers from the abdominal wall
What happens to the gubernaculum and processus vaginalis
-Gubernaculum degenerates, and stalk of Processus Vaginalis degenerates, but the distal expansion remains as the Tunica Vaginalis, the serous sheath of the testis & epididymis
structure of tunica vaginalis
peritoneal sac surrounding the testes. Visceral layer next to testes and parietal layer internal to the internal spermatic fascia. Between the layers are serous fluid.
List the layers of the scrotum from outside to in
dartos > external spermatic fascia > cremaster muscle > external spermatic fascia > parietal tunica vaginalis > visceral tunica vaginalis
Cryptorchidism
undescended testes. Often unilateral, prevalence ~3% full term births, often self-resolves. Testis may be lodged anywhere along normal course of descent- abdominal, inguinal, prescrotal
components of the external sac of the testes
heavily pigmented skin and dartos fascia internally.
Structure of the dartos fascia
contains fibers of the dartos muscle and forms septum of scrotum, dividing the sac. Continues anteriorly with scarpa fascia and posteriorly with colles fascia
Function of dartos muscle
contracts skin of scrotum
tunica albuginea
Tough outer surface of testes. Extends internally as fibrous septa btw lobules of seminiferous tubules
seminiferous tubules
Long, highly coiled tubes in which sperm are produced
Joined to the Rete Testis by Straight TubulesLong, highly coiled tubes in which sperm are produced
Joined to the Rete Testis by Straight TubulesLong, highly coiled tubes in which sperm are produced
Joined to the Rete Testis by Straight TubulesLong, highly coiled tubes in which sperm are produced
Joined to the Rete Testis by Straight Tubules
rete testis
Collects sperm from the tubules. Passes them to Efferent Ductules, which transports the sperm to the epididymis
Epididymis
posterior side of testes. Convoluted duct with 3 regions: head > body > tail.
contents of spermatic cord
ductus deferens, testicular artery (from abd aorta), pampiniform venous plexus, artery of ductus deferens, vestige of processus vaginalis, plus other smaller structures: cremasteric artery, autonomic fibers, genital branch of genitofemoral nerve, lymphatic vessels
coverings of spermatic cord
internal spermatic fascia (from transversalis fascia), cremasteric fascia (containing cremaster muscle, from fascia of internal oblique muscle), and external spermatic fascia (from aponeurosis and fascia of external oblique muscle)
testicular torsion- what is it, most common cause, Sx
Spermatic cord becomes twisted superior to upper pole of testis. Most commonly linked to congenital malformation of the Processus Vaginalis permitting more movement of cord/testis. Sx: edema (venous drainage is obstructed), blockage of arterial blood supply, necrosis
varicocele- what is it, what causes it
Abnormal enlargements (dilations) of the pampiniform plexus of veins in the spermatic cord. Causes: : Incompetent or absent valves within the testicular veins, enlarged lymph nodes/ masses in retroperitoneum block testicular veins (painful), or Nutcracker syndrome ((impingement of Lt renal v. between superior mesenteric a. and aorta, may cause backflow into Lt testicular v)
function of seminal glands
-secrete thick alkaline fluid w/ fructose (nutrient for the sperm) and a coagulant
function of prostate
-secrete prostatic fluid that makes up ~20% of semen by volume, play a role in activating sperm
Parts of the male urethra
bladder > intramural urethra > prostatic urethra > membranous urethra > spongy/penile urethra > navicular fossa > external urethral orifice
- Explain why an enlarging prostate (as in benign prostatic hypertrophy) often leads to urinary symptoms
Enlarging prostate projects into bladder, distorts and compresses prostatic urethra. Impedes urination. May lead to nocturia, dysuria and urgency. Increases risk of bladder infections
function of bulbourethral glands
produces a mucus-like secretion during sexual arousal. Embedded in external urethral sphincter
what is the prostatic utricle
Remnant of the Mullerian ducts. A short blind pouch projecting posteriorly between the ejaculatory ducts. Located between the openings of the ejaculatory ducts
know the location of bladder, uterus, rectum relative to eachother in female
uterus is superior to bladder, anterior to rectum. The uterus is inferior to the peritoneum creating the vesicouterine pouch and rectouterine pouch
what connects the ovaries to the uterus
ovarian ligament- remnant of upper gubernaculum
parts of the fallopian tubes
ovary > infundibulum (have fimbriae) > ampulla (where fertilization happens) > isthmus > uterus
layers of uterus
perimetrium (external wall), myometrium (smooth muscle, distends during pregnancy and contracts during labor, assists in menstruation cramps), and endometrium (layer where blastocyst implants, shed monthly)
Broad ligament of uterus
double layer of peritoneum which acts as a mesentery for uterus. Consists of mesovarium (suspends ovaries), mesosalpinx (surrounds uterine tubes), and mesometrium ( inferior to the other 2 parts and acts as a mesentery for uterus)
ovarian ligament
Tethers the ovary to the uterus medially, just inferior to the entrance of the uterine tube
suspensory ligament of ovary
Peritoneal fold, becomes continuous w/ mesovarium. Contains ovarian blood vessels, lymph vessels, nerves
round ligament of uterus
Also a remnant of gubernaculum. Ataches to uterus near junction of uterine tube and the labia majora via inguinal canal
cardinal ligaments
aka transverse cervical ligaments- Supravaginal cervix + lateral vagina to lateral walls of pelvis.
aka transverse cervical ligaments- Supravaginal cervix + lateral vagina to lateral walls of pelvis.
aka transverse cervical ligaments- Supravaginal cervix + lateral vagina to lateral walls of pelvis.
uterosacral ligaments
cervix to middle of sacrum
anterior and posterior vaginal fornix
located on either side of vaginal part of cervix. Blind pouches
blood supply to ovaries
Ovarian a. from abdominal aorta
blood supply to uterus
Uterine a., from Internal Iliac a. Anastomoses w/ Ovarian a.
blood supply to uterine tubes
Tubal branch of ovarian arteries. Tubal branch of uterine arteries ascending branch
Blood supply to vagina
Superior part: Vaginal br. From Uterine a. Middle Part: Vaginal a. from Uterine a. Inferior Part: from Internal Pudendal a.
borders of perineum
pubic symphysis, ischial tuberosities and sacrum/coccyx
urogenital diaphragm
Old concept: equivalent to the deep perineal pouch
superficial perineal pouch boundaries
space b/w Perineal Membrane (superiorly/deep) and the Perineal Fascia/Colles Fascia (inferiorly/superficially
deep perineal pouch boundaries
space b/w pelvic diaphragm (superiorly/deep), and Perineal Membrane (inferiorly/superficially). It is open superiorly
Contents of deep perineal pouch
Both sexes: urethra surrounded by sphincter urethrae muscle. Males: Deep transverse perineal muscle, bulbourethral glands, dorsal nerve and vessels of penis. Females: smooth muscle, vagina, dorsal nerves and vessels of clitoris
contents of superficial perineal pouch in males
erectile bodies (corpus cavernosums, corpus spongiosum), perineal body, bulbospongiosus, ischiocavernosus, superficial transverse perineal msucle, pudendal nerve branches and internal pudendal vessels
internal structure of penis- erectile bodies, vessels
2 corpora cavernosa, 1 corpus spongiosum. Each is covered by tunica albuginea, and a deep fascia of penis (superficial to albuginea). Contains superficial and deep dorsal veins (above and below deep fascia), deep arteries in corpora cavernosa
- Describe the peripheral neural pathways controlling penile erection, emission and ejaculation
erection: parasympathetic (S2-S4) via cavernous nerves from prostatc plexus. Cause blood dilation of cavernous spaces in corpora. Emission: Sympathetic (L1-L2). Contraction of ductus deferens and ejaculatory ducts. Ejaculation: sympathetic (L1-L2). Contraction of internal urethral spincter plus contraction of bulbospongiosus muscle (perineal branch of pudendal nerve, S2-S4)
Causes of erectile dysfunction
hormone deficiency, neuro disorders, inadequate vascular supply, psychological problems
components of vulva
mons pubis, labia majora, labia minora, clitoris, vestibule of the vagina, vestibular glands (greater and lesser)
greater vs lesser vestibular glands
greater: Secrete mucus into vestibule of the vagina during sexual arousal. Ducts open at 5 and 7 o clock relative to vaginal orifice. Lesser: secretes mucus to moisten labia and vestibule. Open into vestibule of vagina between urethra and vagina
contents of superficial perineal pouch in females
clitoris, bulb of vestibule, bulbospongiosus muscle, greater vestibular glands, urethra, perineal body, superficial transverse perineal muscle, erectile bodies, pudendal nerve branches and internal pudendal vessels
innervation of female perineum
Bulv of vestibule and erectile bodies of clitoris: PSNS innervation via cavernous nerves. Anterior vulva: lumbar plexus L1-L2, anterior labial nerves. Lateral vulva: perineal branch of posterior cutaneous nerve of thigh. Posterior/central vulva: sacral plexus S2-S4, pudendal nerve branches.
nerve blocks in female perineum
pudendal nerve block, ilioinguinal nerve block (may still feel sensation from anterior pudendum). These block somatic nerves and do not block pain from uterine contractions
main blood supply to perineum in males and females
internal pudendal artery
