lecture 5 male pelvis Flashcards
female vs male pelvis: shape of inlet (important)
oval/round vs narrow/heart shaped
female vs male pelvis: sub pubic angle (important)
wide (>80) vs narrow (50-60)
female vs male pelvis: ischial spines
not projecting medially vs projecting medially
female vs male pelvis: false pelvis
shallow vs deep
female vs male pelvis: true pelvis
wide shallow and cylindrical vs narrow deep and tapering
female vs male pelvis: distance between symphysis pubis and anterior margin of acetabulum:diameter of acetabulum
1/>1 vs <1
in the anatomical position of the pelvis (appears tilted downwards and backwards), what are in the same plane
ASIS and pubic tubercle
in the anatomical position of the pelvis, what are continuous
greater and lesser pelves
patietal peritoneum in pelvis: does it enter
yes but doesn’t reach pelvic floor
is pelvic viscera completely covered by peritoneum, and what is the structure of the viscera
no except uterine tubes (part of uterus covered), forming several folds and pouches
what does the space between pelvic wall and peritoneum not covered by viscera contain
pelvic fascia
what do pelvic fascial condensations form and what is its role
form ligaments which support viscera like cervix, vagina and prostate
contents of male pelvic cavity (contents from GI, urinary and reproductive systems)
part of ureter, bladder urethra; prostate ductus deferens, seminal vesicles, bulbourethral glands; rectum; some of abdominal GIT spills into greater pelvis (e.g. caecum, appendix, parts of sigmoid colon and ileum); vessels, nerves and lymphatics
pathway of sperm in pelvis
ductus deferens from testis, inguinal canal, over, behind ureter, enters urethra through prostate
where does the boundary of the pelvis and perineum occur in relation to curvature of urethra
between the two normal curvatures, with the axes just enclosing the anal canal opening (rectum within pelvis); contains penis and testis
what structures in male pelvis can be felt in digital rectal examination of a healthy man
prostate gland, seminal vesicles if calcified
which of the two bends of the male urethra can be straightened before passing a catheter
2nd bend (1st below prostate gland cannot be straightened so catheter must be negotiated carefully as passes from perineum to pelvis)
what part of the utethra does the prostate gland surround
1st (prostatic) part
where do seminal vesicles on back of bladder open into ductus deferens
between ampulla of ductus deferens and ejaculatory duct
where do levator ani muscles hang
from pelvic walls to superior fascia of urogenital diaphragm
what muscle forms lining of pelvic cavity
obturator internus
what does the bladder “sit” on
prostate
where are bulbourethral glands located
either side of urethra in between superior and inferior fascia of urogenital diaphragm, above perineal membrane
what do bulbourethral glands produce
clear secretion to lubricate urethra
what are bulbourethral glands above
root of penis (including corpus cavernosum on either side which all contain erectile tissue and bulbospongiosus), central is through which urethra runs
what is root of penis attached to
perineal membrane
duct of ductus deferens
1 on each side; bring sperm from testis and ends in large ampulla
duct of seminal vesicle
1 on each side; produce secretions
what happens when both ductus deferens and seminal vesicle join
sperm and secretions mix together and form ejaculatory duct (1 on each side) which opens into prosthetic urethra
what is present at neck of bladder
smooth muscle internal urethral sphincter (involuntary by sympathetic nervous system) - well developed in males so during ejactuation seminal fluid doesn’t enter bladder
what nervous systems are involved in ejaculation
somatic, sympathetic and parasympathetic
where does urethra go through to reach skeletal external urethral sphincter, and what is within this
prostatic urethra, within which are ejaculatory duct and prostate gland openings
where can tip of urethral canal become lodged in
prostatic utricle (small, blind-ending space on urethra wall) within prostatic urethra
sections of urethra and length (from start to end)
preprostatic (1.5cm down), prostatic (2.5cm down), membranous (2cm down and 1st bend horizontally), spongy (15cm to external urethral orifice)
where are 4 areas of narrowing or obstruction for catheter
external urethral orifice (navicular fossa is narrowest; if it can go through here can go through entire urethra), 1st bend immediately below external urethral sphincter, prostatic part
arterial supply of male pelvis: inferior vesical artery and branches
from anterior internal iliac artery to prostate (prostatic branch), bladder and ductus deferens (also supplied by superior vesical artery)
where do testis arterial supply come from
testicular artery from abdominal aorta
what marks the diamond shape of male perineum anatomical bony landmarks
pubic symphysis, ischial tuberosities, coccyx
what marks the diamond shape of male perineum in living anatomy in lithotomy position
thighs when person lies on back with thighs flexed and abducted (laterally)
what triangles is perineum divided into
anterior (urogenital) and posterior (anal)
what is present in posterior (anal) compartment
ischio-anal fossae
what are the ischio-anal fossae
fat-filled spaces separating anal canal and levator ani from pelvic walls
what potential spaces is the anterior (urogenital) triangle divided into by perineal membrane
below: superficial; above: deep spaces (“pouches”); if urethra ruptures in superficial space, it becomes urine filled and enlarged
embryology of urogenital triangle
by default develops male but after 6 weeks if no Y chromosome will develop as female
male vs female: urogenital triangle (perineal membrane)
penis vs vagina and cervix
male vs female: anal triangle
no difference
what separates perineal spaces (pouches)
perineal membrane
structure of perineal membrane
thick, triangular fascial structure attached to pubic arch; posteriorly has free margin and anteriorly has small gap
where is deep perineal space located
above perineal membrane, below fascia of pelvic diaphragm
where is superficial perineal space located
below perineal membrane and perineal fascia
male superficial perineal structures (all muscles are skeletal but are usually involuntary)
superficial transverse perineal muscle; bulb of penis (median erectile tissue covered by bulbospongiosus muscle; contains corpus spongiosum erectile tissue), crus of penis either side of bulb (lateral erectile tissue covered by ischiocavernosus muscle attached to ischiopubic ramus; contains corpus cavernosum erectile tissue), meet to form body of penis (contains single corpus spongiosum with urethra running through) up to glans of penis; all anchor to perineal body above superficial transverse perineal muscle
in females what does median erectile tissue divide round to form
vestibule to form vestibular bulbs
what do medial and lateral erectile tissues meet to form in females
clitoris
deep perineal structures of males
bulbourethral glands (above perineal membrane) and ducts open into urethra
common structures in anal triangle in males and females
rectum, anal canal
blood supply of rectum and anal canal
upper: superior rectal artery; middle: middle rectal artery; (both upper and middle from inferior mesenteric arteries) lower: inferior rectal artery (from internal iliac artery)
significance of similar venous drainage to blood supply of rectum and anal canal
important portal-systemic venous anastamosis around lower rectum and anal canal
ischioanal fossa inferior to perineal membrane on either side of rectum
fat-filled space which allow recto-anal and vaginal expansion; lateral wall is pudendal neuro-vascular bundle supply perineum, including lower rectum (careful during surgery)
male reproductive tract
testis in scrotum → vas deferens → superficial inguinal ring → inguinal canal → deep inguinal ring → vas deferens → ampulla joins duct of seminal vesicle → becomes ejaculatory duct → joins urethra in prostate gland
% of secretion from prostate and seminal vesicles
60% secretion from prostate, 40% from seminal vesicles; testis only bring sperm
significance of prostate in ejaculation
fibromuscular tissue contracts
structures in spermatic cord (superficial to deep) and from which muscle
external spermatic fascia (from external oblique) → internal spermatic fascia (from transversalis fascia) → cremasteric fascia (from internal oblique)
testicular artery supply
from gonadal artery below renal artery from abdominal aorta
testicular veins drainage
right drains into inferior vena cava, left drains into left renal vein
testis and associated structure
spermatozoa produced in seminferous tubules then moved to rete testis; go through efferent ductules to head, then body, then tail of epididymis, where stored until ejaculation where it goes through vas deferens
erectile tissues in penis
single cylinder of corpus spongiosum with spongy urethra traversing its length (glans part of corpus spongiosum), corpus cavernosum (paired on either side and ends at glans); wrapped in fascia
skin of penis
above have prepuce/foreskin, below have frenulum/prepuce
which part of corpus cavernosa attac to ischiopubic rami
crura (legs)
blood supply of penis (from internal iliac)
main from internal pudendal artery from internal iliac; deep artery supplies corpus cavernosa; dosral artery supplies skin and connective tissue; artery of bulb supplies bulb, corpus spongiosum, glans and urethra
branches supply cavernous spaces
usually coiled (helicine arteries)
effect of parasympathetic stimulation on helicine arteries
relax causing blood flow
nerves of pelvis
autonomic; sympathetic from T10-L2 via superior hypogastric plexus; parasympathetic from S2-S4 via inferior hypogastric plexus
where is pelvic pain referred
subrapubic region and perineum (somatic)
sensory somatic pudendal nerve from S2-S4: sensory and motor
sensory: dorsal nerve of penis to penile skin, glans; motor: perineal muscles bulbospongiosus and ischicavernosus causing ejaculation and external urethral sphincter (skeletal)
parasympathetic nerves from S2-S4 functions
vasodilation of arterioles in erectile tissue, secretion in prostate and bulbourethral glands
sympathethic nerves L1-L2 function
contraction of smooth muscles of epididymis, vas deferens, seminal vesicles, prostate causing ejaculation; contraction of internal urethral sphincter to prevent reflux of semen
what does erection parasympathetic pathway allow
pudendal artery to dilate so blood flows into cavernous spaces of erectile tissue
during secretion what is stimulated
parasympathetic ganglia on prostate, seminal vesicles and other glands
