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Primary Evidence of Learning Assessment: Spinal Neurosurgery Notes #2
Date: February 23, 2016
Topic: Neurosurgery/Orthopedic Surgery
MLA/APA Citation:
http://www.mayfieldclinic.com/PE-AnatSpine.htm
Preview:
In this Evidence of Learning Assessment I will be continuing from where I left off in my
previous Spinal Neurosurgery Notes. In the last set of notes I talked about the cervical region of
the spine and the various imaging methods that can be utilized when analyzing the cervical
extremities. Conversely for this Evidence of Learning Assessment, I will be detailing the spine as
a whole and the specific techniques neurosurgeons use to understand the spinal cord.
Notes:
Identification Basics
Neurosurgeons utilize many identification
techniques when examining the spinal. As I
discussed in previous notes, the spinal cord is
divided into five distinct regions. These include
the cord’s Cervical, Thoracic, Lumbar, Sacral
and Coccygeal regions. As seen in the diagram to
the right, each section of the cord is labeled with a
capital letter, followed up by a number. This
technique allows neurosurgeons to precisely locate
and indicate points of disorder or injury in the
spinal cord. In doing so, neurosurgeons are also
effectively capable of communicating and
working in teams to perform spinal surgeries.
In short, the cord is organized in a segmented manner. There are a total of 31 segments,
along with 31 nerve bundles exiting the cord and branching out throughout the body.
Furthermore, there are 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal nerve, as seen
in the above diagram.
The Spinal Sheaths
Contrary to popular belief, the spinal cord is not protected by the spine alone. The cord is
encased in three neuromuscular meninges, similar to the brain. These include:

The Pia Mater (AKA: The Pia): Forms the innermost sheath out of the three meninges.
This layer sticks firmly to the surface of the spinal cord. *As a side note: The Spinal Cord
is composed of white matter.

The Arachnoid: Forms the middle layer, between the Pia and the Dura, and is made up of
thin ligaments that connect the dura with the pia.

The Dura Mater (AKA: The Dura): Forms the tough outer layer (sheath) of the three
meninges. The Dura is interconnected with the spinal cord through a series of microligaments that sprout from the pia. (See The Arachnoid) The Dura is also covered in
ventral roots which are thin extensions of the spinal nerve bundles.
In the diagram below, a visual representation of the three sheaths is presented in a lateral and
cross-sectional view. As seen below, the three sheaths encase the central canal of the spinal cord
which includes the main stem of the spinal cord.
Hence, the three meninges represent just one factor that neurosurgeons must account for when
performing Complex Spinal Surgery. Neurosurgeons must also display accurate technical skills
when operating on the fragile layers of the sheaths, as well as the spinal bundles/ventral roots. In
conclusion, the meninges represent the three cases of the spinal cord which form a barrier of
protection and connection between the spinal cord and the body. It is through these three sheaths
that neurons branch out and reach all the extremities of the body.