hello anatomy colleagues this is dr alsup and we will be talking about the spatial relationships
and identifying the viscera of the internal pelvis and we have much to do here so let's
get right into it okay i always always like to look at a hemisection when discussing visceral
relationships in the internal pelvis so just to review a hemisection is formed by a sagittal cut
this time as close to the midline as possible to form a right and a left hemisection we are looking
here at an internal view of the left hemisection of the pelvis and the reason we anatomists like
to start with these views is that it allows us to view all of the structures in the pel the
pelvic cavity whereas with a superior view or a posterior view often you can only see some of the
the more superior structures and not really able to see the deeper structures
i always also like to start with the osteology or the bones just because they help me get oriented
and organized as to what is anterior and what is posterior so you can see where the pubic symphysis
is located right here so that gives you an idea that this is going to be the anterior portion
and you can see portions of the sacrum here i'm outlining obviously it's been cut so
you can look in to the kind of spongy bone portion you can even see a bit of the coccyx
right here and so now we know that this is mostly posterior
now if you if we're going to start anterior just behind the pubic symphysis is the urinary
bladder which is right here um and you can even see a little bit of the relatively short
urethra kind of extending inferiorly from the bladder region just posterior to the bladder is
the uterus in this individual so the of the three major visceral structures in this region
the uterus is always going to be intermediate so right here we are talking the body of the uterus
we'll come back to this in a bit more detail in a moment now i want to look
at the structures kind of up in this area as i think these are a little bit trickier
this is going to be the internal iliac artery we'll talk more about that in the vasculature
video and you can see the numerous branches throughout
this structure right here running between the internal iliac artery and the external iliac
artery over here so this structure that i'm outlining is actually going to be the ureter
so the ureter is and you can see it running between these two
these two arteries and you can see it kind of diving more laterally to head towards the bladder
so it's going in the right direction so pretty good idea that that's going to be the ureter there
extending laterally from the uterus you are going to have the uterine tube
i'm just kind of outlining in this general region here you can actually see where i'm kind
of circling right here the infundibulum portion which you can see a bit of those kind of fringed
outline back here which are part of the fimbriae of the infundibulum of the uterine tube
also you can see the ovary right here so very close approximation
to the uterine tube and to those fimbriae and not too far from the uterus
returning to the uterus so as i mentioned this larger portion that i've already outlined this
is going to be referred to as the body of the uterus and the inferior third of the uterus
is called the cervix so this is the cervix portion or the cervical portion of the uterus
and right here you can see the vagina so this kind of muscular tube region right
here you can see the vagina will actually the superior portion of the vagina will
surround the portion of the cervix that protrudes into the vagina so
this general region that i'm going to outline is going to be the vagina
lastly the most posterior visceral structure before you get down and past the pelvic diaphragm
will be the rectum and as you get to the pelvic diaphragm this will transition into the anal canal
we'll talk more about that when we get to the perineal portion of the the curriculum
okay excellent i love this view i promise you will likely see some practical questions
in this hemisection view but let's take some of a look at some of these visceral
structures in other views as well so this is a superior view on an individual with the uterus
the uterus is going to be located right here it is the fairly dominant structure
but it's also covered with peritoneum as you can see here the broad ligament is extending on either
side of the uterus towards the lateral pelvic wall the uterine tubes are going to be superior
and extending laterally so the uterine tubes on either side
it's going to be covered with peritoneum as you can see here specifically the mesosalpinx of the broad ligament and you can see portions of the uterine tube
you can see the infundibulum kind of stretching out into this region and you can see the fimbriae
that are going to be associated with that distal most portion of the infundibulum
and right at the end of the distal most portion is going to be the abdominal osteum which would
be right in this region you can't really see the opening very well in this image but that is where
the uterine tube is actually opening um into the abdominopelvic cavity
and you can see a little you can see the ovary right here on the left side as well so
again very closely associated with the uterine tube into those fimbriae of the infundibulum
so you have the uterus the uterine tubes and the ovaries they're going to be intermediate in
place in the pelvic cavity the bladder is always going to be anterior and usually it's difficult
to see in a superior view as it is covered by quite a bit of peritoneum sometimes you'll have
a little bit of fat associated with it but it's going to be deep to this general area right here
and the rectum will be posterior you can see a bit of it here it's been tied off in this dissection
but generally without anything removed the uterus the broad ligament
is going to be fairly dominant in this view
all right let's talk internal bladder structures obviously you can only see
these internal structures if you've made an incision into the bladder and portions reflected
in order to better view it which is certainly what has happened here in fact some of the superior
bladder has been removed this whole general region is actually the bladder it's been opened
quite large in order to see the internal views and to get our bearings right here is going to
be the uterus you can see extension over here that's going to be the uterine tubes
now right here i'm going to circle them you can see these tiny slit like openings which are your
ureteric orifices so your your uroteric orifices where the ureters are entering the bladder
and in close proximity and generally a little bit larger and more in the midline
is going to be the internal urethral orifice and when you kind of connect
these regions this forms the trigon of the bladder
all right last view of internal pelvic visceral relationships with an emphasis
right now with individuals who have a uterus present
and we're going to focus a little bit more on this image on the parts of the uterine tubes
so this is the uterus here and you can see the broad ligament is extending laterally to
the pelvic wall so the broad ligament is this whole general area right here
the superior most portion of the broad ligament is going to be referred to as the mesosalpinx and
this is what's actually covering the uterine tube so the superior most portion of the broad ligament
is actually covering almost all the the surfaces of the uterine tube the lateral most portion
of the uterine tube is the infundibulum so i'm just going to kind of label it in its general area
there's no really clear demarcations but it is going to be the distal most portion you will have
the fimbriae which you can see kind of extending all over the place in this general region
and the portion of the infundibulum that opens into the abdominopelvic cavity is the
abdominal osteum which is not very clear here but it would be in this general area
so this whole general complex right here is part of the infundibulum the ampulla is the
longest portion of the tube this is generally where fertilization will occur if it does and
then the isthmus is going to be the portion of the uterine tube that begins to narrow and is
close to the uterus and like i mentioned there are no clear demarcations between these parts
the ovary will be near the infundibulum portion of the uterine tube and you
can see that the fimbriae are very or relatively close to the ovary as well
all right excellent great work so far working through these structures with me now let's take
a look at a hemisection of an individual assigned male at birth so let's find those
osteological structures i told you to find first in a hemisection so here is the anterior pubic
symphysis right here and posterior you're going to have the sacrum and the coccyx back here so sacrum
and coccyx so we know this is posterior we know we're looking more anteriorly here just of note
the penis is not considered part of the internal pelvic viscera but you can clearly see the penis
in this image and the erectile tissues that help compose the penis so this is penis right here
and back to the pubic symphysis as always just behind the pubic symphysis you're going to have
the urinary bladder and you can see the ureter let me outline the ureter real quick again traveling
between the internal iliac artery and the external iliac artery on its way towards the bladder
inferior to the bladder is going to be the prostate gland and this is
it's difficult to differentiate in this particular individual where the bladder ends
and the prostate begins it may have to do with where the incision or the cut actually occurred
but just note that the prostate is always going to be inferior
and superior to the prostate gland are and kind of more posteriorly placed are the ampulla of ductus
deferens and the seminal gland the ductus deferens and this ampulla is just kind of the wider portion
of the ductus deferens is always going to be more superiorly placed so ductus deferens
and then the seminal gland sometimes you hear this referred to as the seminal vesicle is
going to be more in or more inferiorly placed in comparison to the ductus deferens and where they
join together this forms the ejaculatory duct and the ejaculatory duct will deposit contents from
the vas deferens as well as the seminal gland into the prostatic urethra lastly you see just
a little bit of the rectum here the majority of the rectum has been removed in this dissection
but as always the rectum is more posteriorly placed so close to the sacrum and the coccyx and
it's right at the level of the pelvic diaphragm that you get the transition to the anal canal
this is another image of the internal bladder but with different surrounding visceral structures
in particular the seminal gland which remember is going to be more inferiorly um excuse me
the seminal gland is going to be more inferiorly placed and the ductus deferens which remember when
we get towards this region kind of right behind the bladder it will dilate forming the ampulla so
you can even see kind of traveling the ductus deferens and then it extends into the ampulla
you can see the same thing over here extending into the ampula of the ductus deferens recall the
ductus deferens will travel within the spermatic cord in the scrotum in the inguinal canal before
making its own way towards this region you don't really have a seminal gland very clear here but it
would be in this general region so ductus deferens ductus deferens and then the seminal glands
now the prostate would be a bit more inferior to the bladder here so we don't see it quite
well in this image the bladder similar to what we saw in the other image has
been incised with some of the superior portion removed you can see the two ureteric orifices
right here and right here and the larger more midline internal urethral meat meatus or orifice
right here and so where these kind of join will be referred to as the trigon of the bladder
now in individuals with a prostate gland the prostatic median lobe will create an elevation
in the internal urethral orifice which is called the uvula so kind of right in this region there'll
be kind of a bump that you wouldn't see in an individual that does not have a prostate gland
like i said this is referred to as the uvula of the bladder if the uvula is hypertrophied
this can obstruct the flow of urine
lastly i wanted to talk through this really excellent dissection and focus on this
posterior view of the prostate and associated structures so to get our bearings most of the
posterior bony structures have been removed as well as the rectum to get a closer view
of this region you can see a bit of where the pelvic diaphragm muscles are located and probably
the the most obvious structure in this dissection is going to be the prostate or the prostate gland
you can see a bit of the bladder right here as well just to kind of get your bearings
so the prostate of course is going to be inferior that's why it's a harder structure to see other
than purely posterior views posterior inferior views or in say hemisection so that's why i wanted
to look at this image as well you can see the more inferiorly placed seminal gland you can't see it
quite as well here it'd be in this general region and then you have the ductus or vas deferens
on either side here and here the ones that i've outlined there and where these two meet so kind
of in this general area will be the ejaculatory ducts and so you'll have one on either side
and those ejaculatory ducts will drain into the prostatic urethra
excellent we have gone through quite a bit of material here but that makes sense as
there is quite a bit of viscera to discuss when we're talking about the internal pelvic viscera
make sure to review these structures and please reach out with any questions you may have
to me or any of my anatomy colleagues thank you for your time and attention and have a great day