Case 4 - Suzi

Front 1

What type of dogs are more likely to get IVDD?

Back 1

Chondrodystrophic breeds typified by the Dachshund and Pekingese

Front 2

What components of the vertebrae result in the spinal canal being properly aligned in an axial plane?

Back 2

The annulus fibrosus of intervertebral disks and dorsal & ventral longitudinal ligaments

Front 3

What area of the spinal cord has less extradural space, making it the site most likely to have clinically significant disk herniation?

Back 3

Thoracolumbar

Front 4

Why does the amount of extradural space make a difference when it comes to disk herniation?

Back 4

If there is more extradural space, there is more room to allow for the accumulation of herniated disk material without substantial compression of the spinal cord

Front 5

Degeneration of intervertebral disks in chondrodystrophic breeds of dogs is a genetically programmed metaplastic change of the ______________

Back 5

Nucleus pulposus

Front 6

What results from the degeneration of the nucleus pulposus?

Back 6

Peripheral to central replacement of the nucleus pulposus with cartilage. Results in the loss of elasticity of the nucleus pulposus, which places additional mechanical stress force on the annulus fibrosus, which itself is experiencing degenerative changes similar to those occurring in the nucleus pulposus

Front 7

At what age does degeneration of intervertebral disks in chondrodystrophic breeds of dogs start to take place?

Back 7

As early as 6 months of age & progresses rapidly.

Front 8

At what location is the annulus fibrosis the thinnest and weakest?

Back 8

At its point of contact with the spinal canal

Front 9

What are the 2 types of disk herniation?

Back 9

Hansen type I and II herniation

Front 10

What is the main difference b/w Hansen type I and type II herniations?

Back 10

Hansen Type I herniation occurs due to trauma. Hansen Type II herniation is a gradual loss of elasticity. Type I causes the most severe spinal cord damage b/c there is insufficient time for the spinal cord to compensate & for collateral circulation to develop, as may occur in type II.

Front 11

At what age is the gradual loss of elasticity of the nucleus pulposus clinically seen in nonchondrodystrophic dogs?

Back 11

by 8-10 years of age

Front 12

What protrudes into the spinal cord with hansen type I herniation vs. hansen type II herniation?

Back 12

In Hansen type I herniation, the nucleus pulposus protrudes (or fragments of it) due to the annulus fibrosus rupturing. In Hansen type II herniation, the annulus fibrosus protrudes due to the gradual loss of elasticity.

Front 13

What are the mechanisms by which disk herniation cause injury to the CNS?

Back 13

The primary injury is caused by the physical trauma of compression & the resulting Wallerian degeneration of affected axons. Also, disk material can compress the vascular supply to a spinal cord segment resulting in ischemia, neuronal excitotoxicity, & necrosis

Front 14

What radiographic signs are suggestive of intervertebral disk herniation?

Back 14

Narrowing or wedging of the disk space, decreased size of the intervertebral foramen, reduced space b/w articular facets, & mineralized disk material in the vertebral canal or overlying intervertebral foramen

Front 15

How is localization of disk herniation determined for surgery?

Back 15

By myelography, CT, or MRI

Front 16

Where are cell bodies of origin for LMN located?

Back 16

Within the brain stem and within the ventral horn of the spinal cord

Front 17

What are the 2 groups of LMN?

Back 17

Alpha-motor neurons and gamma-motor neurons

Front 18

What is the difference b/w alpha-motor neurons and gamma-motor neurons?

Back 18

Alpha-motor neurons are the LMN's that innervate the voluntary muscles. Gamma-motor neurons are LMN's that innervate the intrafusal muscles of muscle spindles.

Front 19

Where are the cell bodies and cell processes of the UMN located?

Back 19

All located entirely within the CNS

Front 20

What do UMN's do?

Back 20

They provide the excitatory & inhibitory influences on the LMN, reflecting reflex activity originating in the spinal cord and brain stem and conscious motor info. derived from the cortex via descending supraspinal pathways

Front 21

Pyramindal system includes descending tracts whose tracts decussate where?

Back 21

In the pyraminds of the medulla oblangata

Front 22

Which descending tracts does the pyramindal system consist of?

Back 22

Lateral corticospinal tract and Corticobulbar tract

Front 23

What's the lateral corticospinal tract's function?

Back 23

Fine dexterous motor control

Front 24

What is the lateral corticospinal tract?

Back 24

Axons leave the cerebral cortex, descend ipsilaterally through the posterior limb of internal capsule of thalamus, the crus cerebri, the pons, & and the pyramids of medulla. They desuccate at the junction of medulla & spinal cord & enter the tract where they continue down the spinal cord. They terminate on cells in ventral horn of spinal cord.

Front 25

Where does the corticobulbar tract terminate?

Back 25

On cells in the cranial nerve nuclei, which supply innervation to the musculature of the head, pharynx, and larynx

Front 26

Which cranial nerves innervate the striated muscles of the head?

Back 26

CN III, IV, V, VI, VII, IX, X, XI, and XII

Front 27

Which tracts does the extrapyramidal system include?

Back 27

Medial & lateral reticulospinal tracts, medial & lateral vestibulospinal tracts, rubrospinal tracts, tectospinal tracts

Front 28

In general, where do extrapyramidal system tracts originate and end?

Back 28

Fibers arise from the brain stem nuclei and synapse with the LMN of the cranial nerves and spinal nerves indirectly through short interneurons

Front 29

At which vertebrae is a lumbar myelography usually performed?

Back 29

Done preferably at L5-L6 (try to avoid L4-L5 to avoid damage to the spinal cord)

Front 30

Where is the ventral aspect of the epidural space wider?

Back 30

Normally wider in the caudal cervical region

Front 31

Where does the canine spinal cord terminate?

Back 31

Around L5-L6

Front 32

True or False:
Postural reactions are always absent in a tetraplegic patient.

Back 32

True

Front 33

What tests can be done to test for postural reflexes?

Back 33

Hopping & hemiwalking

Front 34

How would a patient with LMN disease react to a postural reflex test?

Back 34

When they must support their own weight, they will fall over or collapse

Front 35

Where is the vertebral canal the widest?

Back 35

Widest at the atlas and tapers within the sacrum. Expanded in the cervical & lumbar areas where the plexuses originate from.

Front 36

What are the three meninges around the spinal cord? (from innermost to outermost)

Back 36

Pia mater, arachnoid, and dura mater

Front 37

Which of the 3 meninges is the toughest layer?

Back 37

Dura mater

Front 38

What does the dura mater fuse with? And where does it split?

Back 38

Fused with the inner periosteum of the skull and bone. Splits at the margin of the foramen magnum to form a free tube.

Front 39

What is the epidural space's function?

Back 39

It is occupied with fat and vessels to cushion the spinal cord allowing movement without damage

Front 40

The dural tube attaches at the caudal end to form a fibrous strand called _________________

Back 40

Filum terminale (which fuses with the upper surface of the caudal vertebrate)

Front 41

Where is the subdural space located?

Back 41

B/w the dura mater and the arachnoid

Front 42

What does the subdural space contain?

Back 42

A small amt of fluid which can increase if blood is allowed to effuse in after an injury

Front 43

What attaches the inner meninges to the dural tube?

Back 43

Denticular ligaments alternate w/the spinal nerves & attach the inner meninges to the dural tube

Front 44

Where the CSF contained?

Back 44

In the subarachnoid space

Front 45

Where are the cisterns of the cranial subarachnoid space located?

Back 45

At the angle b/w the cerebellum and the medulla

Front 46

What is the cistern called by the skull and the atlas (atlantooccipital space)?

Back 46

Cerebellomedullary cistern (injection can be given here)

Front 47

What is the widening called that is around the lumbosacral joint?

Back 47

Conus medullaris

Front 48

What is the CSF composed of?

Back 48

Largely composed of ependymal lining of the ventricular system and contribution to the fluid is produced by pial vessels. Has high concentrations of potassium & calcium.

Front 49

What is the function of CSF?

Back 49

Protects brain w/buffering capabilities. Transports nutrients, flushes away waste, & serves as a medium of diffusion for neuroendocrine & neurotransmitter substances.

Front 50

What is the pathway of the CSF flow?

Back 50

Fluid is moved by filtration process & ciliary activity of the ependymal lining. Escapes from interior of brain to move to bathe the brain & cord & then connects w/the blood thru arachnoid granulations (villI).

Front 51

What does examination of the spinal reflexes test for?

Back 51

It tests the integrity of the sensory & motor components of the reflex arc and the influence of descending motor pathways on the reflex

Front 52

What are the 3 kinds of responses that may be seen with spinal reflexes?

Back 52

Absent or depressed response, which indicates complete or partial loss of either sensory or motor (LMN) components of reflex. Normal response indicates both sensory & motor components are intact. Exaggerated response indicates abnormality in motor pathways (UMN).

Front 53

What position should animal be in when performing spinal reflex tests?

Back 53

Lateral recumbency

Front 54

What is considered the most reliable myotatic reflex?

Back 54

Patellar reflex

Front 55

What is the grading system for the patellar reflex?

Back 55

0 - +4 (0 is absent, +1 is depressed, +2 is normal, +3 is exaggerated, +4 is exaggerated w/clonus)

Front 56

What does absence of a myotatic reflex indicate?

Back 56

Indicates a lesion of the sensory or motor component of the reflex arc (a LMN or segmental sign). Loss of the reflex in one muscle group = peripheral nerve lesion. Bilateral loss of the reflex = segmental spinal cord lesion affecting motor neurons to both limbs located in L4-L6

Front 57

What does depression of the arc reflex signify?

Back 57

The same relative significance as absence, except the lesion is incomplete

Front 58

What does exaggeration of the arc reflex signify?

Back 58

Loss of descending inhibitory pathways. Bilateral exaggeration most often indicates damage to descending inhibitory pathways cranial to the level of the reflex.

Front 59

What does exaggeration of the cranial tibial reflex indicate?

Back 59

A lesion cranial to the spinal cord segments L6-L7 (interpret with caution b/c this reflex is difficult to elicit in normal animal)

Front 60

What does a response to the perineal reflex indicate? What about absence of the response?

Back 60

Indicates integrity of the sacral spinal cord segements and nerve roots. Evaluation of this reflex is especially important in animals w/urinary bladder. Absence or depression of the reflex indicates a sacral spinal cord or pudendal nerve lesion.

Front 61

What is the cutaneous/panniculus reflex?

Back 61

Twitch of cutaneous muscle in response to cutaneous stimulus. Most prominent in "saddle" area of trunk in horses. Cannot be elicited over the sacrum or the neck.

Front 62

If a lesion is disrupting the superficial pain pathway, where would the response be absent?

Back 62

Response is absent caudal to the lesion that disrupts the superficial pain pathway

Front 63

Sensory nerves of skin enter by the ___________

Back 63

Dorsal root

Front 64

Synapse occurs bilaterally at ______ segments with motor neurons of the lateral thoracic nerve. These innervate the cutaneous trunci muscle.

Back 64

C8, T1

Front 65

Deep pain causes the animal to show a change in behavior. What are some changes in behavior that would indicate deep pain?

Back 65

Anxiety, attempt to escape, turning of head, vocalization

Front 66

What parts of the brain does the deep pain pathway go to?

Back 66

Reticular formation, thalamus, and cerebral cortex

Front 67

In the spinal cord, loss of function occurs in this sequence:

Back 67

1. Loss of proprioception
2. Loss of voluntary motor function
3. Loss of superficial pain sensation
4. Loss of deep pain sensation (closer to gray matter in the spinal cord than other fibers)

Front 68

What are the 3 categories for surgical approaches to IVDD?

Back 68

1. Decompression technique
2. Stabilization technique
3. Preventative disk fenestration

Front 69

How is the decompression technique achieved?

Back 69

Removal of the dorsal or lateral components of vertebral arch to relieve pressure on spinal cord. It creates window thru vertebral bone so spinal canal can be entered & examined for compressive masses of material (which are then removed)

Front 70

Is the stabilization technique used in IVDD?

Back 70

Seldom used since disk herniation rarely destabilizes the vertebral column

Front 71

How is the preventative disk fenestration performed?

Back 71

Sx procedure creates an opening thru the ventral disk annulus fibrosus. Removal of nucleus pulposus by perforation & curettage of IVD space.

Front 72

Where is the preventative disk fenestration usually performed?

Back 72

Usually performed in cervical area (C2/3 - C5/6 or C6/7) and thoracolumbar area (T11/12 - L2/3 or L3/4)

Front 73

Which blood vessels supply the bladder?

Back 73

Caudal vesicle artery (indirect branch from the internal iliac) and the cranial vesicle artery (branch from umbilical artery)

Front 74

Which nerves innervate the bladder?

Back 74

Hypogastric nerve (sympathetic), pelvic nerves S1-S3 (parasympathetic), and pudendal nerve S1-S3 (somatic)

Front 75

Why are epithelial cells in the bladder called "transitional" ?

Back 75

Epithelial cells are transitional in that when the bladder is empty the layers are piled giving stratified appearance. When full, thinner epithelial stratification gives way.

Front 76

What is the oblique angle in the bladder that prevents backflow when the bladder is filling?

Back 76

Ureterovesicular junction (from ureter to bladder)

Front 77

In the kidney, urine flows thru the nephron tubules from hydrostatic pressure gradient b/w ___________ & _____________

Back 77

B/w Bowman's capsule and the renal pelvis

Front 78

Where does the micturition reflex control come from?

Back 78

Sacral region of spinal cord and brain stem

Front 79

What happens when bladder is being stretched from filling?

Back 79

Activation of sacral spinal reflex. Allows urine to be evacuated & the external sphincter. Afferent impulses simultaneously received at the brain stem reflex ctr, which prevents contraction of bladder & relaxation of sphincter.

Front 80

Once the urge to void (due to pressure) arrives, how does micturition proceed?

Back 80

Voluntary control.

Front 81

What is oliguria?

Back 81

Decreased urinary output

Front 82

What is anuria?

Back 82

No urine output

Front 83

What is stranguria?

Back 83

Slow, dropwise, painful discharge of urine caused by spasm of the urethra & bladder