Membranous Urethra
HIDEInteractive Transcript
0:01
Let's talk about the membranous urethra,
0:04
which is one of the components, the inferior
0:07
component, of the posterior urethra, which
0:10
means there's got to be an anterior urethra,
0:12
which begins at the bulb and goes into
0:15
the penis and then the external meatus.
0:17
Set that aside again and focus on the membranous
0:20
urethra, which is the continuation or lies
0:23
just inferior to the lower prostatic urethra.
0:28
And here it is in the axial projection.
0:29
These are all 2D, 3-millimeter, heavily
0:33
water-weighted T2 fast spin echo images.
0:37
So in the coronal projection, this is a
0:39
direct coronal orthogonal, sagittal, and axial.
0:43
We see the urethra coming down towards this dark
0:47
U-shaped area, more inferiorly, between these
0:51
two muscle bellies, the membranous urethra.
0:55
Now, the membranous urethra in the axial
0:57
projection is only about one centimeter long.
1:02
So, if you're using three-millimeter cuts, you're
1:04
only going to see it for three slices in total.
1:08
In the membranous segment is the external
1:10
sphincter and also two paired Cowper's glands.
1:15
Can you see the Cowper's glands?
1:17
Sometimes you can.
1:18
For instance, on this coronal image, there is
1:20
the right Cowper's gland opening just adjacent
1:24
to the membranous urethra on the right.
1:27
And it does communicate with
1:28
the urethra, although we don't have the
1:30
resolution to see that communication.
1:34
In the axial projection, I'm gonna make
1:35
it a little bigger. In the membranous
1:38
urethra, you can divide it up into a
1:41
brighter central area, which is white.
1:44
Now, all you have to remember is white,
1:46
dark, white, dark for the zones
1:50
down in the membranous urethra.
1:52
So white in the middle, central zone.
1:55
Then you have an inner area that you
1:57
can barely see, it's pretty thin, dark.
2:01
Then you have a middle area which is
2:03
a little bit brighter and thicker.
2:06
Brighter and then dark around the periphery.
2:10
So white, dark, white, dark.
2:16
Central, inner, middle, outer.
2:22
And that, my friends, is the membranous urethra.
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
© 2024 Medality. All Rights Reserved.