Spinal Cord Disorders Flashcards
List the 2 divisions of the motor neurons and describe their individual functions
- Lower Motor Neurons (LMN)- connect the CNS (usually the spinal cord) with the target muscle/organ/gland
- Upper Motor Neurons (UMN)- control the lower motor neurons
Draw:
- where the spinal cord is in relation to vertebra and intervertebral disks
- transverse section of spinal cord indicating locations of motor and sensory axons
Draw it
List 4 commonly tested spinal reflexes of the hindlimb
Patellar
Cranial tibial
Gastrocnemius
Withdraw
Patellar Reflex
- nerve
- spinal cord segments
Femoral
L4-5; occasionally L3, L6
Cranial Tibial Reflex
- nerve
- spinal cord segments
Peroneal nerve
L6-7, S1
Gastrocnemius Reflex
- nerve
- spinal cord segments
L6-7, S1
Withdrawal Reflex
- nerve
- spinal cord segments
Sciatic nerve
L6-S1; sometimes S2
What are the clinical signs for Upper Motor Neuron (UMN) lesions?
paresis
increased muscle tone
normal reflexes or hyperreflexia
disuse muscle atrophy (slow development, mild to moderate)
What are the clinical sings for Lower Motor Neuron (LMN) lesions?
Paresis
decreased muscle tone
areflexia or hyporeflexia
Neuro muscle atrophy (rapid development, severe)
2 Most common methods by which a Dz may create spinal cor dysfunction
Compression of the cord
Disruption of blood supply to the cord
List 3 different causes of spinal cord compression
- Material from the center of the intervertebral disk extrudes into the spinal canal around the cord, causing compression of the cord (IVDD)
- Severe hemorrhage or the formation of a clot within the canal
- Neoplasia in form of a mass lesion within the canal
Describe Type I IVDD
- location of nucleus pulposus
- speed of onset
- most common in…
Nucleus pulposus extrudes through annulus fibrosis into ventral portion of spinal cord
- occurs acutely with sudden development of clinical signs
- most common in dachshund, cockers, shih tzu, beagle, mini poodle
Describe Type II IVDD
- location of nucleus pulposus
- speed of onset
- breeds most common
Disk material degenerates and gradually moves into spinal canal, but nucleus pulposus remains in place
- more gradual onset without intensity of Type I
- German shepherds, lab retrievers
How do different degrees of spinal cord compression influence clinical sings
Mild –> some motor axons are compressed, but sensory axons are not; decreased conscious proprioception but intact voluntary motion function and sensation
Moderate –> compressed enough motor axons to decrease conscious proprioception and voluntary motor function; sensory axons may start getting compressed leading to decreased superficial pain
Severe –> loss of deep pain; poor prognosis
How to eval a patient for deep pain
use a hemostat or needle holders to pinch the base of a toe; can also used needle/pin power of the skin; see if P REACTS with more than just pulling the foot away
