Localisation of lesions in ruminants

Question 1

Whloe body

• Opisthotonus
• Blindness (with intact PLR),
• Abnormal mentation, behaviours and vocalisation
• Aimless wandering, propulsive circling
• Seizures

Where is the lesion?

Answer 1

Cerebrum

Question 2

Whole body

• Ataxia without weakness, hypermetric gait, truncal sway
• Absent menace response (care: neonates)
• Wide base stance, intention tremors

Where is the lesion?

Answer 2

cerebellum

Question 3

• Head tilt (towards lesion)
• Falling/leaning/circling (towards lesion)
• Nystagmus (slow phase to lesion)
• Proprioceptive deficits (on side of lesion)
• Depression (especially if brainstem involvement)

Where is the lesion?

Answer 3

Vestibular system - central lesion (CNVII or brainstem)

Question 4

• Head tilt (towards lesion)
• Falling/leaning/circling (towards lesion)
• Nystagmus (slow phase to lesion)

Where is the lesion?

Answer 4

Vestibular system - peripheral lesion (CNVIII)

Question 5

cranial nerve signs

Blindness and abnormalities of ocular movement and positioning.
Abnormalities of smell (difficult to assess)

Lesion location?

Answer 5

cranial nerves I-IV

Question 6

cranial nerve signs

Sensory and motor deficits of the face.
Vestibular abnormalities.

lesion location?

Answer 6

cranial nerves V-VIII

Question 7

cranial nerve signs

Motor deficits to the tongue and swallowing abnormalities.
Neck/shoulder muscle abnormalities.

lesion location?

Answer 7

cranial nerves IX -XII

Question 8

cranial nerve signs

Depression in addition to cranial nerve deficits

lesion location?

Answer 8

Reticular activating system of brainstem – i.e. CN root lesion at brainstem rather than peripheral lesion

Question 9

spinal signs (i.e. brain not affected)

Reflexes in forelimbs depressed to absent.
Reflexes in hindlimbs exaggerated.
Muscle tone reduced in forelimbs and normal in hindlimbs.

Lesion location?

Answer 9

C6 to T2 vertebrae

Question 10

spinal signs (i.e. brain not affected)

Abnormalities of the head/neck movement but no CN abnormalities.
Hyperreflexia (exaggerated reflexes) of all four limbs.
Increased extensor tone –> ataxia.
Proprioceptive deficits when circling (inside limb).
Lateral recumbency if severe cervical lesion (cranial to C4) present.
Normal mentation.

Lesion location?

Answer 10

C1 to C5 vertebrae

Question 11

spinal signs (i.e. brain not affected)

Forelimb muscle tone and reflexes normal.
Hindlimb reflexes and muscle tone exaggerated/increased
Hindlimb proprioceptive deficits present.
Dog sitting may be observed in large ruminants.

Lesion location?

Answer 11

T3 to L3 vertebrae

Question 12

spinal signs (i.e. brain not affected)

Forelimb muscle tone and reflexes normal.
Hind limb reflexes absent and reduced hindlimb muscle tone.

Lesion location?

Answer 12

L4 to L6 vertebra

Question 13

spinal signs (i.e. brain not affected)

Decreased anal tone, tail tone, and perineal sensation.
May have urinary incontinence.

Answer 13

S1 to S3 vertebrae

Question 14

Localise the lesion:
Rostral to foramen magnum:
* Whole body affected
* Abnormal mentation

Answer 14

cerebrum (forebrain)

Question 15

Localise the lesion:
Rostral to foramen magnum:
* Whole body affected
* normal mentation

Answer 15

Cerebellum

Question 16

Localise the lesion:
Rostral to foramen magnum:
* Face/head only.
* Mentation usually normal mentation (can be depressed)

Answer 16

cranial nerves (brainstem)

Question 17

Localise the lesion:
caudal to foramen magnum:
* All 4 limbs affected
* Not head/face/mentation

Answer 17

Cervical and cranial thoracic spinal cord (C1-T2)

Question 18

Localise the lesion:
caudal to foramen magnum:
* hindlimbs only

Answer 18

Thoracolumbar spinal cord (T3-L6)

Question 19

Localise the lesion:
caudal to foramen magnum:
* tail/perineum only

Answer 19

Sacrococcygeal spinal cord (S1-S3)