2. Neuronal Receptors
• Sense organs have 3 major forms
• The ones relevant to articular neurology are
neuronal receptors
• They are sensory neurons whose end is the
sensory terminal
• All cutaneous sensors and proprioceptors are
probably of this type
3. Mechanoreceptors
• Receptors are classified in several ways; e.g. by
the specific energy forms to which they are
especially sensitive
• Mechanoreceptors are responsive to
deformation (touch, pressure, sound waves
etc.)
• Mechanoreceptors are responsible for
transmitting information about the joint status
to the central nervous system
4. Role of Mechanoreceptors
They protect the joint from injury in 3 ways:
• Avoid movement of the joint in the pathologic
range
• Help balancing the activity between
synergistic and antagonistic muscle forces
• Generate an image of body position and
movement within the central nervous system
5. Type I mechanoreceptors
• Ruffini receptor endings
• Thinly myelinated
• Located in superficial layer of joint
capsule.
• Function: informs about static and
dynamic position of the joint,
contributes to the regulation of
postural muscle tone and kinesthetic
sense.
• More active for ends of range
• Pain inhibiting
6. Type II mechanoreceptors
• Pacinian corpuscles.
• Location: Sparse, found in deeper
layers of capsules and ligaments.
• Function: informs about acceleration
and deceleration of joint movement.
• Act at initiation of movement to
overcome inertia.
• Not active in mid range of
movement
• Pain inhibiting.
7. Type III mechanoreceptors
• Golgi tendon organ-like endings
• Location: in intrinsic and extrinsic joint
ligaments and superficial layers of the capsule,
but not in ALL, PLL and ISL
• Function: reflex inhibition of muscle tone,
monitors direction of movement
8. Discharge only when:
• Joint is placed at endrange
• Axial traction is applied
• Joint is manipulated
• Forces are in kg’s, not in grams
9. Type IV mechanoreceptors
• Free, non-capsulated nerve endings
• Unmyelinated or very thinly myelinated
• Seen in hypoxic or ischemic tissue and inflammatory
exudates
• Function: active only when related tissue is subjected
to marked deformation or noxious stimulation
• Pain provoking
• Non adapting
• High threshold
10. Located in
• Joint capsules
• Fat
• Blood vessels
• Anterior dura mater
• Ligaments
• Connective tissue
11. Not found in
• Hyaline cartilage
• Synovial tissue
• Blood vessels in the brain
14. Regeneration
• A degree of regeneration possible
• Lots of repetitions, rhythmic stabilization, and
self-mobilizations will activate
mechanoreceptors without putting undue
stress on the damaged tissue
