 So, this is supine cadaver. I am on the right side. Camera percent is on the left side. We have completely dissected all the structures in the pelvis and this structure that we see in front of us, this is the urinary bladder. This is the apex of the bladder and we can see this ligament arising from the apex. This is the median umbilical ligament which is the remnant of the urex which is derived from the alan toy and this goes and gets attached to the umbilicus on the inner surface of the anterior abdominal wall. We see these two ligaments on either side. These are the medial umbilical ligaments which are the obliterated distal portions of the umbilical artery which is a branch from the anterior division of the internal iliac. These also go to the umbilicus. In life, these structures are located on the inner surface of the anterior abdominal wall and there is a depression on either side of the median umbilical ligament here and here. These are called the supraviscicle fossa which can be a potential site of herniation. To continue, we have opened out the space between the bladder and the pubic symphysis. This is known as the pre-viscicle space. This is filled with endopelvic fascia. This space is also referred to as the cave of redsias. In life, this is filled with vesicle venous plexus which becomes continuous with the prostitic venous plexus. Normally, the bladder is below the level of the pubic bone in trapelvic organ but when the bladder gets distended and for some reason we cannot pass a catheter through the urinary passage, we have to do what is known as a suprapubic systostomy and we do the suprapubic systostomy through this root where my instrument is pointing. To continue with the parts of the bladder, this surface of the bladder was covered by peritoneum and this is the dome of the bladder and this peritoneum which we have removed continues and gets reflected onto the rectum which is this structure here. The place where the peritoneum gets reflected from the bladder to the rectum that is known as the recto vesicle pouch. In females, uterus is lying on the dome of the bladder so therefore there will be a vesico uterine pouch. Any portion after that is extra peritoneum and we will come to that in a little while. We will pick up the bladder to show you this portion now. This portion is known as the fundus. It is extra peritoneum. The fundus of the bladder is also called the base of the bladder because it is opposite the apex it is also the posterior surface of the bladder. This is the structure which is in relation to the rectum separated by the recto vesicle septum and it contains three structures in the male and we can see the two structures here. One of them is the ductus difference which is going inside and then we have the ureter which is also going and there will be a structure which is not visible but further lower down and that will be the seminal vesicle. So these are the three structures which are separating the posterior surface or the base of the bladder from the rectum and the recto vesicle septum and to show it more clearly I will lift up the bladder and we can see this is the ductus difference here on this side and the ductus difference on this side and we can see the ductus difference here becomes a little dilated. This is known as the ampoule of the ductus difference which will then unite with the duct from the seminal gland and form the common ejaculatory duct which will go through the prostate and open as the common ejaculatory duct into the prostate ureter. This is a post-operative case so therefore this whole area was highly fibrosed but we can see a few of the blood vessels which are coming to the bladder from the proximal portion of the umbilical artery and these are the superior vesicle arteries on this side and these are some remnants of the superior vesicle artery on this side. They are the ones which supply the dome of the bladder. The ductus difference gets supplied by branch from the inferior vesicle artery and these are known as differential arteries. The inferior vesicle artery is also a branch from the anterior division of the internal iliac. Now let's take a look at the interior of the bladder and for that we have sliced open the bladder on its anterior surface and I have tilted the bladder back and we have opened the bladder. This is the interior of the bladder. We can see first of all the bladder mucosa. It is thrown into slight folds. After that this is the thickness of the bladder wall. This contains a smooth muscle which is referred to as the detrusor muscle. This detrusor muscle is under parasympathetic control. Parasympathetic causes contraction and sympathetic causes relaxation of the bladder and if we look very closely here we can see a triangular shaped structure here. This is the trigon of the bladder. This trigon is located in the floor of the bladder. What are the components of this trigon? We can see this structure which I have lifted up here and when I pull we can see it is exerting traction on the ureter on this side. Similarly when I pull here we can see it is exerting traction on the ureter on this side. So these are the openings of the two ureters. The ureters when they enter the bladder they enter in a beveled fashion. The purpose being to prevent vesico-urotric reflux in normal circumstances. Therefore it acts as a valvular mechanism. When this valvular mechanism fails then we get what I mentioned as the vesico-urotric reflux. For the same reason this ureter vesicle junction is also a potential site of ureteric constriction where a small stone more than 0.5 centimeters can get impacted. In which case there will be hydrourator and hydronephrosis. This is an axial CD scan at the level of the hip joint to show a right UVJ calculus and right hydrourator. If we look further closely we will see a ridge joining the two openings of the ureters. This is referred to as the inter-urotric bar. Lower down we can see yet another opening here. That is the opening of the urethra. That is the internal urethral meatus which is also encircled by smooth muscle which is the internal urethral sphincter. This is relaxed by the parasympathetic and contracted by the sympathetic. So therefore parasympathetic is for mixturation purpose. This trigon of the bladder is derived separately from the rest of the bladder. Bladder is derived from endoderm of the urogenital sinus while the trigon is derived from the misodermal wolfian duct. Mucosa of the trigon is very sensitive. When we are doing a urethroscopy examination of the bladder and we reach the internal urethral meatus at that position we cannot see normally the two openings of the ureter. However when we advance the urethroscope even further then we can see these two openings. That is the normal situation. However when the patient has got benign hypertrophy of the prostate then the internal urethral orifice is pushed up by means of the median lobe of the prostate and that is referred to as the uvula of the bladder and in which case we get a condition known as marion's sign positive. What is this marion's sign positive? It means that in the same cysto urethroscopic view we can see all the three orifices simultaneously. So when a patient has got enlarged prostate the median lobe is enlarged there is a depression behind the median lobe of the prostate and that is known as the post-prostatic pouch. Whenever the patient lies down there is irritation of the post-prostatic pouch, the trigon of the bladder by means of residual urine and that is what produces nocturia and frequency in a patient with benign hypertrophy of the prostate. I have again come to the posterior surface or the base of the bladder to show the unique relationship of the ductus difference and the ureter. So I have pulled it up to show you the normal relationship and we can see that the ureters are crossed over by the ductus difference on either side. This is because during embryonic life the testis descends down and the kidneys ascend up and so therefore this is the place where the ductus difference crosses the ureter. This can rarely be a site of constriction of the ureter where again a stone can get impacted. So these are the points that I wanted to mention to you about the bladder and the related structures in the pelvis. Thank you very much for watching Dr. Sanjay Sanyal, please like and subscribe. If you have any questions or comments please put them in the comment section below. Have a nice day.