Jumb0

5+ Year Member
Aug 24, 2012
239
111
USA
Status
Pre-Medical
A lot of sources, including my professor's notes, say that the lumbar enlargement of the spinal cord is found in the L1-S3 region of the spinal cord and that it is superior to the conus medullaris...Uhhh, how is that possible when the conus medullaris terminates at L2 ??? If the terminal part of the spinal cord is at L2, how does the "enlargement" continue all the way to S3?

Is there something painfully obvious that I'm missing?

EDIT: I think I may have figured it out. When they say that the conus medullaris occurs at L2, they are referring to the vertebra (not the spinal cord segment), whereas the enlargement location is given in terms of spinal cord segments (which are not adjacent to the vertebra of corresponding # because the spinal nerve must travel inferiorly in the cauda equina before it exits the spinal cord inferior to the corresponding vertebra). Is this correct?
 
Last edited:

mehc012

Big Damn Hero
7+ Year Member
Jul 9, 2012
9,323
8,340
The Black
Status
Medical Student
A lot of sources, including my professor's notes, say that the lumbar enlargement of the spinal cord is found in the L1-S3 region of the spinal cord and that it is superior to the conus medullaris...Uhhh, how is that possible when the conus medullaris terminates at L2 ??? If the terminal part of the spinal cord is at L2, how does the "enlargement" continue all the way to S3?

Is there something painfully obvious that I'm missing?

EDIT: I think I may have figured it out. When they say that the conus medullaris occurs at L2, they are referring to the vertebra (not the spinal cord segment), whereas the enlargement location is given in terms of spinal cord segments (which are not adjacent to the vertebra of corresponding # because the spinal nerve must travel inferiorly in the cauda equina before it exits the spinal cord inferior to the corresponding vertebra). Is this correct?
:thumbup: your edit.
 
Feb 26, 2016
107
71
Status
Medical Student
Is there something painfully obvious that I'm missing?
Seems you got it
The part about it being superior to conus medullaris seems awfully redundant, as it has to be superior by definition.

Also, semantics I suppose but spinal nerves do not travel that far down. The roots that make up the cauda equina travel to their respective IVF where they combine to become nerves.

The lumbar enlargement is also quite obvious if you look at the conus medullaris. It gets fat right before it tapers off.