Upcoming Events
Log In
Pricing
Free Trial

Sagittal Anatomy

HIDE
PrevNext

0:01

Okay, let's take a look at some prostate anatomy.

0:04

In the sagittal projection, in the midline,

0:06

the patient is lying on their back.

0:09

So this is going to be anterior,

0:11

this is going to be posterior.

0:13

And you've got the base, the middle of the

0:16

gland, or mid-gland, and apex of the gland.

0:20

You can see this curious angle from

0:22

anterior proximal to posterior distal of the

0:26

urethra, and then it goes straight on down.

0:28

Here's the central urethra

0:29

and the periurethral tissue.

0:31

And then we've got the fibromuscular

0:33

zone, which is pretty thin.

0:34

In the midline.

0:35

This is a midline diagram.

0:38

So we're going to help you through the

0:40

transition of anatomy off to the side when we

0:43

look at a live MRI where the anatomy changes

0:46

a little bit and the peripheral zone becomes

0:48

more prominent but stay tuned for that.

0:51

Around the urethra you mostly have the TZ or

0:54

transitional zone portion of the central gland

0:57

depicted here in yellow and it's probably a

1:00

little bit of TZ Uh, behind the urethra as well.

1:04

So let's put a little yellow over here too.

1:07

So some more TZ.

1:09

And then in orange we have the CZ.

1:11

So together these make up the, the central gland.

1:15

Now as you get older, unfortunately, the

1:19

central gland, and especially the central

1:22

zone, gets bigger and bigger and bigger

1:26

and starts to encroach on the urethra.

1:29

So you can have trouble urinating.

1:32

And also we have structures

1:33

that we haven't drawn in yet.

1:34

Like this one in purple, the seminal vesicle.

1:38

So it'll start to press

1:39

against the seminal vesicle.

1:42

And then anteriorly we've also got the bladder.

1:45

We have the bladder right here.

1:49

towards the base of the bladder.

1:51

And it'll lift the bladder

1:52

up and indent the bladder.

1:54

And sometimes when you have really profound

1:56

BPH, it'll get kind of fluffy and lobulated and

2:00

it'll start to look a little bit like broccoli.

2:03

Now let's take this anatomy and let's

2:07

rotate it into the projection that

2:09

you're going to look at with MRI.

2:12

Now for those of you MR aficionados,

2:15

which hopefully all of you are, let's

2:17

look at the sagittal projection in the

2:19

way that you would view it as an imager.

2:23

So this would be anterior,

2:24

this would be posterior.

2:26

Here's your bladder.

2:27

And we've got the urethra coming down

2:29

from the bladder right here, making

2:30

that angle that we talked about.

2:33

And around the urethra, in the midline,

2:36

is gonna be the transitional zone, or TZ.

2:40

Gonna have a TZA and a TZP.

2:42

And then we've got the central

2:44

zone, which is posterior superior.

2:46

And it's this one.

2:48

Along with some TZ hypertrophy, they

2:50

can get really, really big and start

2:52

to press on the base of the bladder.

2:54

And sometimes it'll even be kind of

2:55

fluffy, a little bit like broccoli, and

2:58

may even encroach upon the seminal vesicle.

3:00

And of course, encroach upon the urethra,

3:03

along with the TZ, which gets bigger

3:05

and causes difficulty in urination.

3:08

In the midline anteriorly, we've

3:10

got the fibromuscular tissue.

3:12

Which on T2 is going to be dark.

3:14

We're not going to show that just yet.

3:17

And then in the back we're

3:18

going to have the, the PZ.

3:20

Now as we go off to the side, the PZ

3:23

is going to wrap around everything.

3:25

So PZ tissue, as you go more lateral, is going

3:29

to take over from the fibromuscular zone.

3:31

And is going to be the predominant

3:33

zone in the periphery, in the

3:35

most lateral cuts on either side.

3:37

You're going to appreciate that on MRI.

3:40

So, so have no fear.

3:41

Now Basic, basic, body coil,

3:45

sagittal, T1 weighted image.

3:48

Um, I've got the stubby little

3:49

seminal vesicle right here.

3:51

Just to orient you, here's the spine in the back.

3:53

Here's the bladder in the front.

3:55

Here's the pubis in the front.

3:57

Here's the pre-prostatic space of Retzius.

4:01

Here is the, the rectum.

4:03

And between the rectum is kind of a

4:04

slit-like area, the Denonvillier fascia.

4:07

The rectoprostatic space.

4:09

But I'm actually showing it for the PZ.

4:12

Because this patient had a biopsy.

4:16

So the biopsy has produced blood.

4:18

And the blood is isolated to the PZ.

4:22

How cool is that?

4:23

So there you see your PZ kind of hooking around.

4:27

Going very deep and apically.

4:30

And cancers occur there.

4:32

When you biopsy the prostate, because the

4:35

cancers are very dense and firm, the blood

4:38

tends not to extrude into the cancer.

4:41

That's known as the prostate exclusion sign.

4:46

So you've got blood infiltrating all around

4:49

the PZ, except in two separate cancers.

4:52

So this patient has cancer, but I'm

4:54

showing it for the shape of the PZ,

4:58

and then you see the rest of the gland.

5:01

Which is relatively faceless on a

5:03

T1 weighted image, which includes the

5:05

fibromuscular zone or anterior stroma,

5:08

the TZ, and the CZ posterosuperiorly.

5:12

Let's move on, shall we?

Report

Editorial Note

Faculty

Stephen J Pomeranz, MD

Chief Medical Officer, ProScan Imaging. Founder, MRI Online

ProScan Imaging

John F. Feller, MD

Chief Medical Officer, HALO Diagnostics. Medical Director & Founder, Desert Medical Imaging. Chief of Radiology, American Medical Center, Shanghai, China.

HALO Diagnostics

Tags

Prostate/seminal vesicles

Neoplastic

MRI

Genitourinary (GU)

Body

© 2024 Medality. All Rights Reserved.

Contact UsTerms of UsePrivacy Policy