Neuroanatomy and Physiology of the Spinal Cord Flashcards
What region of the neural tube lies ventral to the sulcus limitans?
Basal plate
What region of the neural tube lies dorsal to the sulcus limitans?
Alar plate
What part of the spinal cord contains primarily motor neurons (efferent)?
Basal plate
What part of the spinal cord contains primarily sensory neurons (afferent)?
Alar plate
Is the spinal cord longer in men or women?
Men (45cm compared to the 42cm in women)
What is the approximate diameter of the spinal cord?
1.0-1.5cm
In adults, the spinal cord ends at what vertebral level?
L1-L2
There are 2 observable enlargements that occur in the spinal cord. Where do these occur?
- cervical
- lumbar/sacral
The 2 observable enlargements of the spinal cord mark what?
mark the areas of the spinal cord that contain the neurons concerned with the upper and lower extremities, respectfully
Rostrally, the spinal cord is continuous with what part of the brainstem?
medulla oblongata
Caudally, the spinal cord tapers into what structure?
conus medullaris
The dorsal and ventral roots of the lower lumbar and sacral segments continue caudally to exit where?
exit through their appropriate intervertebral foramina
What makes the dorsal and ventral roots so long?
due to the differential growth of the spinal cord versus the spine
The collection of these long dorsal and ventral roots is known as?
cauda equina
What are the three layers of meninges that cover the spinal cord?
–> these coverings of the spinal cord vary somewhat to that surrounding the brain
1) dura mater
2) arachnoid
3) pia
Which layer of the spinal cord consists only of a meningeal layer?
Dura mater
The periosteal layer ends where?
foramen magnum
The epidural space is filled with what?
fat
The arachnoid mater acts as the limiting component to contain what substance?
CSF
When does the CSF get into the subarachnoid space of the spinal cord?
after leaving the foramina of Luschka and Magendie
Since the spinal cord ends at the level of L1-L2, that leaves a large pocket of subarachnoid space below the caudal tip of the cord….this space is known as what?
lumbar cistern
In what space is it safe to perform lumbar punctures (spinal tap)?
lumbar cistern - subarachnoid space below the caudal tip of the cord
What are the 2 components of the pia mater?
1) pia intima
2) denticulate ligaments
Which component of the pia mater is adhered directly to the spinal cord, much the same as with the brain?
pia intima
Extensions that protrude from the lateral sides of the cord and pierce the arachnoid to attach to the dura mater are called what?
denticulate ligaments
What is the function of the denticulate ligaments?
help anchor and stabilize the spinal cord in the vertebral canal
At the caudal end of conus medullaris, what ligament extends to anchor the spinal cord?
filum terminale
What is the filum terminale made up of ?
- pia
- glial elements
- some remnants of coccygeal neuronal elements
What is the filum terminale termed, as it extends through and becomes encased with the dura mater attached to the coccyx?
coccygeal (sacral) ligament
What is the function of the coccygeal (sacral) ligament?
anchors the end of the cord in the spinal canal
Why is it safe to perform a lumbar puncture (spinal tap) in the lumbar cistern?
At the level of the lumbar cistern the nerve roots are suspended in CSF and therefore float away from the pressure of the needle.
What are the 4 segments of embryological segmental organization? (similar to segmental development of the spinal cord)
- somites
- dermatomes
- myotomes
- sclerotomes
How many pairs of spinal nerves are there?
31 (32) nerves
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 (2) coccygeal