C h e c k o u t A B M P 's l a t e s t n e w s a n d b l o g p o s t s . Av a i l a b l e a t w w w. a b m p . c o m . 43
FUNCTIONAL ANATOMY
education
Joint Mechanoreceptors
By Christy Cael
Continuing our examination of proprioception that
began in the March/April 2016 issue ("Muscle
Spindles," page 45), we will now examine the
role of articular mechanoreceptors. These sensory
structures reside around and within synovial joints and
use mechanical deformation to register and report joint
position, movement direction, and movement speed.
The information gathered by joint mechanoreceptors tends
to be subtler than that of their muscular counterparts, as these
structures are activated by relatively small amounts of stimulus
(low threshold detection). Despite this, the information
they provide has significant influence over neuromuscular
control mechanisms, influencing the activity of the entire
proprioceptive system at multiple segments in the kinetic chain.
The three types of articular mechanoreceptors are:
Type I, Ruffinian—Globular or ovoid
corpuscle with a thin capsule.
• Located in outer layer of joint capsule
• Low threshold detection (sensitive to fine movements)
• Slow adaptation
• Constantly firing to maintain posture
Type II, Pacinian—Cylindrical or conical corpuscle
with thick, lamellated, or plated capsule.
• Located within deeper layers of joint capsule
• Low threshold detection (sensitive to fine movements)
• Rapid adaptation
• Activity quickly ceases when joint stops moving
Type III, Golgi-like—Fusiform corpuscle with thin capsule.
• Located in intrinsic and extrinsic ligaments
• High threshold detection (sensitive to extreme movements)
• Slow adaptation
• Inhibitory effect to slow or limit harmful movements
Images courtesy Mikkel Juul Jensen Science Photo Library.
Type I, Ruffinian—Globular or ovoid
corpuscle with a thin capsule.
Type II, Pacinian—Cylindrical
or conical corpuscle with thick,
lamellated, or plated capsule.
Type III, Golgi-like—Fusiform
corpuscle with thin capsule.
Three Types of Articular Mechanoreceptors