Exam #1: Organization of the Spinal Cord Flashcards
Where is the cervical enlargement of the spinal cord?
C5- T1; this is the origin of the nerves destined for the upper limb i.e. the roots of the brachial plexus
Where is the lumbosacral enlargement?
L2-S3; this is the origin of the nerves destined for the lower limb i.e. the lumbosacral plexus
Where is the common site for a LP? Why?
L3-4 or L4-5
**Cord ends at L2 (conus medullaris)–not going to hit the spinal cord; this space below the conus medullaris is known as the lumbar cistern
Where do the cervical nerve roots emerge?
Above the vertebrae
*****Remember that there are 8 cervical spinal nerves, but only 7 cervical vertebrae
Where do the lumbar nerve roots emerge?
Below the vertebrae
What is the spinal nerve?
The distal continuation of the dorsal & ventral roots, once they join together
What is the gray matter of the spinal cord?
“H” or butterfly in the center of the cord
- Nuclei
- Processes
- Neuroglia
*Not myelinated
What is the white matter of the spinal cord?
Outside of the H
- Tracts, fasiculi, commisures
*Myelinated
What are the cross sectional differences between the cervical and sacral regions?
- Cervical region has the most white matter/ highest white:gray ratio
- Descending the spinal cord, the amount of white matter generally decreases
- In the sacrum, white matter is the least
What are the three general areas of the gary matter?
Dorsal horn/ column
Lateral horn/ column
Ventral horn/column
What is the dorsal horn of the gray matter?
Cell bodies of the pseudounipolar neurons
What is the ventral horn of the gray matter?
Cell bodies of the motor neurons
What is the lateral horn of the gray matter?
Preganglionic sympathetic neurons
What levels of the spinal cord contain a lateral horn?
T1- L2 i.e. the levels that contain sympatheitc ganglia
What does the intermediate zone contain? Where is the intermediate zone?
This is the area between the dorsal & ventral horns of the gray matter that contains interneurons