Lecture 6

Question 1

What are the characteristics of Schiff-Sherrington posture?

Answer 1

-severe paraparesis/paraplegia with increased extensor tone in the thoracic limbs
-occurs due to acute, severe thoracic or lumbar lesion
-does not indicate irreversible lesion

Question 2

What are the characteristics of proprioceptive positioning?

Answer 2

-want to support patient under chest or abdomen
-evaluate time it takes for patient to return paw to normal position after “knuckling”
-assesses ascending conscious proprioception pathways and descending motor pathways
-sensitive for spinal cord lesions; this reaction is often lost before motor function

Question 3

What are the characteristics of hopping reaction?

Answer 3

-position animal to bare weight on one limb and move laterally; animal should hop
-sensitive test for weakness
-allows for left vs. right comparison

Question 4

What are other postural reactions that can be tested in animals?

Answer 4

-wheelbarrowing/walking with hind limbs lifted off ground
-placing/reaching to place feet on table/surface

Question 5

How do reactions differ from reflexes?

Answer 5

-reactions must go to the brain and back; larger area for potential lesion
-reflexes are more local

Question 6

What are the characteristics of the patellar/myotatic reflex?

Answer 6

-tapping on stifle causes stretch in the quad. muscle
-quad. muscle contracts and extends stifle
-evaluates femoral nerve and L4 to L6 spinal segments

Question 7

What are the characteristics of an exaggerated patellar reflex?

Answer 7

-leg keeps flexing and extending rather than a single extension with tap
-occurs with an UMN lesion; less inhibition of spinal reflexes

Question 8

What are the characteristics of flexor/withdrawal reflex in the hind limb?

Answer 8

-extend limb and pinch toe to stimulate pain receptors
-leg should flex away from stimulus
-want hip, stifle, and hock to all flex
-evaluates sciatic nerve and L6 to S1 spinal segments

Question 9

Which nerves are evaluated with flexor/withdrawal reflex in the front limb?

Answer 9

-most nerves in the thoracic limb
-C6 to T2 spinal segments

Question 10

What are the characteristics of deep pain perception?

Answer 10

-evaluates whether pain perception reaches the brain
-need to see a conscious response; looking, yelling, biting
-carried by small, un-myelinated axons; conducts slowly and is the last thing to disappear with a lesion

Question 11

What are the characteristics of superficial pain perception?

Answer 11

-tested by pinching just the skin
-disappears before deep pain when a lesion is present

Question 12

What are the characteristics of crossed extensor reflex?

Answer 12

-extension of contralateral limb when ipsilateral limb is tested in flexor reflex
-normal in standing animals to maintain standing/balance
-abnormal in recumbent animals; indicates UMN lesion
-almost always bilateral

Question 13

What type of lesion is more likely to cause exaggerated spinal reflexes?

Answer 13

chronic lesions

Question 14

What are the characteristics of the perineal reflex?

Answer 14

-evaluates the pudendal nerves and S1 to S3 spinal segments
-touch response only
-want to test left and right side
-external anal sphincter should constrict and tail should drop
-important in patients with urinary and/or fecal incontinence

Question 15

What are the characteristics of the cutaneous trunci reflex?

Answer 15

-tests the muscle underlying the thoracic and lumbar skin
-stimulate the skin along the spine looking for a twitch
-synapses on lower motor neurons upstream
-good test for lesions localized between T3 and L3; can work up each vertebra and see where the lesion is

Question 16

What are the characteristics of palpating for spinal pain?

Answer 16

-focal spinal pain is localized
-want to place pressure on each spinous process
-want to feel abdominal muscles for contraction as you palpate
-can also flex and extend the neck