Specialized receptors for proprioception measure:
posiiton in space with specialize receptors
Muscle spindles sense
golgi tendon organs sense
joint angle and tendon tension
Conscious pathways carry proprioception to terminate at the
cerebral cortex- parietal lobe (somatosensory cortex)
Un-conscious pathways carry proprioception to terminate at the
Propriception cannot be tested if a patient is:
unconscious or paralyzed
How can you test proprioception?
during locomotion, gait abnormalities or while standing
Where are proprioception tracts located?
superficially located in the peripheral spinal cord
what part of the brain integrates afferent information to make a 3 D map of the body in space?
parietal lobe- cerebrum
What are the two primary pathways conscious proprioception info gets toeh brain?
DCML pathway (dorsal column- medial lemniscus and Trigeminal Pathway
Trigeminal pathway carries
ascending CP info about our face
DCML pathway (dorsal column, medial lemniscus) pathway carries
ascending CP info about our limbs and body
Make physiologic changes in relation to body language:
by altering our proprioceptive afferents can alter cortisol, serotonin and endorphins
DCML Pathway receptor include:
golgi tendon organs
What innervates muscle spindles and golgi tendon organs?
mechanoreceptive primary nerve endings
**primary sensory neurons
Where are the cell bodies of primary afferent neurons?
in the dorsal root ganglia
from pelvic limb
from thoracic limb
- spinal cord segment
- fasciculus gracilis/cuneatus carry signals
- Decussation of 2nd order neuron
- 3rd order neuron carries signal to cerebral cortex
Proprioception from facial skin and oral cavity is carried by
Proprioceptive clinical signs include:
gait abnormalities (ataxia), knuckling, draggin or scuffing of toes or failure to pass Conscious propriception tests
Postural reaction tests include:
proprioceptive positioning, wheelbarrowing, hopping, hemistanding/hemiwalking, placing(with/without vision)
proprioceptive ataxia caused by
a lesion in the proprioceptive pathway( peripheral nerve, dorsal root, spinal cord, brainstem, cerebral cortex)
Prprioceptive ataxia clinical signs:
abnormal postural reactions with paresis
Vestibular ataxia caused by :
lesion in the vestibular apparatus (vestibular nuclei, CN VIII, or vestibular receptors)
Vestibular ataxia clinical signs:
head tilt, leaning/falling/rolling, abnormal nystagmus, strabismus, abnormal postural reaction, crouched posture
What is normal in a dog with vestibular ataxia?
normal postural reaction with peripheral lesions (No CP deficits)
Cerebellar ataxia is caused by a lesion located
in the cerebellum
Clinical signs of Cerebellar ataxia:
abnormal rate, range and force of movement; no paresis, wide based stance, intention tremors, truncal sway, nystagmus, etc.
What kind of diseases do not cause proprioceptive deficits?
vestibular and cerebellar
Why is proprioception vulnerable to injury?
large size of axons and superficial location on the spinal cord
If proprioception is lost what sensation is lost next?
motor (voluntary), then pain sensation