Lecture 2: the Spinal and Autonomic Nerves (part 1 of 2) Flashcards
define encephalopathy
a disease in the brain
define myelopathy
a disease in the spinal cord
define peripheral neuropathy
a disease in the peripheral nerves
the presence of what 4 conditions differentiates peripheral neuropathy from CNS encephalopathy and myelopathy?
- hyporeflexia, hypotonia (less muscle tone)
- “denervation” atrophy
- unilateral motor and/or sensory deficits
- normal function cranial and caudal to nerve lesion site
are cenral lesions usually unilateral or bilateral?
bilateral
what are the 4 main branches of spinal nerves?
- dorsal branch
- ventral branch
- communicating branch
- meningeal branch
what are the 4 anatomical parts to the typical spinal nerve?
- roots
- main trunk
- the four primary branches
- peripheral branches of these primary branches
where are roots of spinal nerves located?
within the vertebral canal
roots of spinal nerves are functionally associated with what?
functionally associated with the spinal cord even though they belong to the peripheral nervous system.
are dorsal roots and spinal (dorsal root) ganglia afferent or efferent in function?
afferent ie sensory
Are ventral roots afferent or efferent in function?
efferent ie motor
describe an identifying characteristic of the main trunk of typical spinal nerves and their location in most cases
it is typically very short and located in the intervertebral foramen
what is the spinal nerve formula for the horse?
C8 T18 L6 S5 Cd7
where does the first cervical nerve emerge from?
it emerges from the lateral vertebral foramen located in the atlas
where does the second cervical nerve emerge from?
it exits from the lateral vertebral foramen of the second cervical vertebrae (axis)
where does the eight cervical nerve run through?
the intervertebral foramen between the seventh cervical and first thoracic vertebrae
how many cervical nerves and cervical vertebrae are there in the horse?
8 cervical nerves but only 7 cervical vertebrae
what does the dorsal primary branch supply?
dorsal axial (epaxial) muscles and skin over the dorsal and dorsolateral body areas
what does the ventral primary branch supply?
supplies ventral axial (hypaxial) muscles, muscles of ventral and ventrolateral regions like the thoracic and pelvic limbs and skin over these regions
what do ventral branches of the lower cervical and thoraci region (C6 - T1 or T2) form?
the brachial plexus
what do ventral branches of L4 - S4 form? what does it supply?
the lumbosacral plexus which supplies the pelvic limb and the perineal region
what does the meningeal branch supply?
it supplies the coverings of the spinal cord (meninges), blood vessels in the vertebral canal, and the intervertebral discs. these are implicated in back pain
what is an identifiable physical characteristic of the meningeal branch?
its is very small - difficult to see grossly
where does the communicating branch (ramus communicans) run?
it runs from the main trunk of a spinal nerve to the sympathetic trunk and chain ganglia