Spinal Cord and its Blood Supply Flashcards
What is the conus medullaris?
The lower end of spinal cord (spine tapers into cone)
What are denticulate ligaments?
Wing-like leaves of pia extending laterally between dorsal and ventral roots
How many bilaterally paired spinal nerves are there?
31
What fibres do posterior nerve roots carry?
sensory fibres
Where are the cell bodies of posterior nerve roots located?
The posterior root ganglia
What fibres do the anterior nerve roots carry?
motor fibres
Where are the cell bodies of the anterior nerve roots located?
anterior horn of grey matter
Where do the anterior and posterior nerve roots unite?
In the intervertebral foramina (cervical and sacral segments are exception)
What does gray matter consist of?
Neuronal cell bodies
What is Rexeds laminae?
The ten divisions of gray matter
Which laminae are located in the posterior horn?
laminae I-V
What do medial fibre types consist of?
Mechanoreceptors
What do lateral fibre types consist of?
Nociceptors
Which laminae are confined to the anterior horn?
Laminae VIII and IX
What does lamina IX contain?
a and y motorneurons that innervate skeletal muscle
What does the lateral horn contain?
intermediate gray matter of laminae VII
What is significant about lamina VII
Its is the site for the lateral horn at thoracic/lumbar/sacral levels where sympathetic and parasympathetic cell bodies are located
Also contains Nucleus Dorsalis
Where is lamina X located?
It encircles central canal
What arteries supply the spinal cord?
The anterior and posterior spinal arteries
How is single vertebral artery formed?
Unification of anterior spinal branches and vertebral arteries on each side
Where do the right and left posterior vertebral arteries arise?
from the posterior inferior cerebellar arteries or directly from vertebral arteries
What level is the cervical enlargement at?
C4-T1
Why is there a cervical enlargement?
For the brachial plexus
What level is the lumbar enlargement at?
T9-L1
What are the filum terminale?
extensions of pia matter from conus medullaris
What do spinal nerves originate as?
Rootlets attached to sulci of anterior and posterior root zones
Where do 1st and 2nd cervical nerve roots unite?
Lateral to intervertebral foramina, in contact with vertebral arteries
Where do sacral nerve roots unite?
inside vertebral canal
Which spinal segments possess lateral horns of grey matter?
thoracic, upper lumbar and sacral segments
What is lamina II?
Substansia gelatinosa- C fibres terminate here
What is lamina I?
zona marginalis
Which laminae do A delta fibres terminate in?
Laminae III-V- Nucleus Proprius
Where doe gating of pain conduction occur?
Substansia Gelatinosa
What is nucleus dorsalis?
Origin of spinocerebellar tracts
What do radicular arteries end as?
Pial arteries
