2-3, Proprioception In Health And Disease, Usman Year One Glasgow Uni

Perception of limb movement, body position and spatial orientation arising from stimuli within the body itself

Movement sense or kinaesthesis - awareness of joint movement

2. Position sense - awareness of the static position of joints

in capsule and ligaments

-Muscle Spindle: primary and secondary endings

-Tendon organ (receptor in muscle)

slow adapting stretch receptors

muscle spindle

Tendon organ

Ruffini ending joint

the output frequency of the joint receptors

yes

yes

sensory receptors within the belly of a muscle that primarily detect changes in the length of this muscle

it is a complex sensory receptor with its own motor innervation (gamma (γ) motoneurones) that innervates intrafusal muscle fibres

(gamma (γ) motoneurones)

the extrafusal muscle fibres

Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors) that detect the amount and rate of change in length of a muscle. They constitute the muscle spindle and are innervated by two axons, one sensory and one motor.

Extrafusal muscle fibers are the skeletal standard muscle fibers that are innervated by alpha motor neurons and generate tension by contracting, thereby allowing for skeletal movement. They make up large mass of skeletal (striated) muscle

• Organs of balance

• Semi-circular canals

• Otolith organs

• Visual input
•Vision influences perception of body orientation

The vestibulo-ocular reflex (VOR), also known as the oculocephalic reflex is a reflex eye movement that stabilizes images on the retinaduring head movement by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field.

-controlled by the semicircular canals

nystagmus (rapid involuntary movements of eye)

Otolith Organs (utricle and saccule)

-clinical sensory examination

-romberg test

Threshold detection paradigm

Knee moved by motor (0.4 deg/sec) and a blindfolded subject stops it when he/she is certain of the direction of movement.

Small angular displacement = good proprioceptive acuity.

Much more sensitive than standard clinical testing.

kinaesthesia or the movement sense

this is done by eliciting the vestibulo-Ocular reflex, the 2 methods used are

-Barany chair

-Caloric Testing

Due to inertia, head movement results in endolymph flow in the semi-circular canals. This deflects the cupula and stimulates hair cells. This in turn affects the extrinsic eye muscles. The vestibulo-ocular reflex stabilizes images on the retina during head movement by producing eye movement in the direction opposite to head movement (in all three planes). Powerful stimulation (e.g. fairground rides) elicits dizziness and nystagmus, and perhaps nausea and vomiting (motion sickness). Injecting water into the external auditory meatus sets up convection currents in the endolymph, the direction being temperature dependent.

Labyrinthitis and vestibular neuritis (infection); Ménière’s disease

Dizziness; vertigo; nausea; vomiting; loss of balance; nystagmus

...all pretty obvs ngl

• Loss of balance; clumsiness; bumping into objects (usually door frames!); knees ‘giving way’; dropping objects

• Often in common with other sensory disturbances (loss of fine touch, numbness, paraesthesia) due to neural injury

• Peripheral neuropathy - examples:

• diabetes mellitus • alcohol abuse

• Peripheral nerve injury • Spinal cord lesion

• vitamin deficiency e.g. B12 , folate • trauma

• Joint hypermobility syndrome
• Joint diseases e.g. osteoarthritis, rheumatoid arthritis