SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
4. If only the head, but not the neck can be raised off the ground, there is
probably a severe cranial cervical lesion.
5. With a severe caudal cervical lesion, e.g., C6, the head and neck can
usually be raised off the ground, although thoracic limb effort will be
decreased and the animal usually will not be able to maintain sternal
recumbancy nor a dog sitting posture.
6. Assessments of limb function must not be done while the animal is lying
on the limb. The muscular tone can be determined by manipulating each
limb. A flaccid limb with no motor activity is typical of a lower motor
neuron lesion to that limb. Beware that in heavy animals that are down for
a day or so, there is frequently poor tone and very little voluntary effort
observable in a limb that has been laid upon.
7. A severe upper motor neuron lesion to the thoracic limbs (cranial to C 6 )
will result in decreased or absent voluntary effort, but there will be normal,
or more likely increased muscle tone in the limbs. This is because there is
usually a “release” of the lower motor neuron that is reflexly maintaining
normal muscle tone, from the “calming” influences of the descending
upper motor neuron pathways.
B. Spinal Reflexes
Spinal reflexes are of value in determining the segmental integrity of the
spinal cord and the peripheral nerves involved in the simple reflex. Included
in the simple reflex are:
1. A peripheral sensory receptor area.
2. Sensory portion of the peripheral nerve and dorsal spinal root.
3. Motor input.
4. Effector organ.
If any component of the reflex arc is non-functional, a negative response will
be seen when attempts to elicit a reflex are made.
Lower motor neuron disease is characterized by hyporeflexia or areflexia;
upper motor neuron disease by hyperreflexia.
C. Patellar Reflex
Patellar reflex is the most reliable tendon reflex and is mediated by the
femoral nerve through L 4 -L 6 .
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