Joint Classification and Receptors

Question 1

Fibrous joints (Synarthroses)

Answer 1

 Nonsynovial with minimal to no movement
 Types
• Suture – Union of two bones by ligament or membrane, immovable (sagittal suture of skull)
• Syndesmosis – bone connected to bone by a dense fibrous membrane, very little motion (tibia and fibula with interosseus membrane)
• Gomphosis – Two bony surfaces connect as a peg in a hole (tooth in socket)

Question 2

Cartilaginous Joints (Amphiarthroses)

Answer 2

 Hyaline cartilage or fibrocartilage that connects one bone to another. Slightly moveable.
 Types
• Synchondrosis – Hyaline cartilage joining two ossifying centers of bone (sternum and rib articulation)
• Symphysis – located at midline of body, two bones covered with hyaline cartilage or two bones connected by fibrocartilage (pubic symphysis)

Question 3

Synovial Joints (Diarthroses)

Answer 3

 Free movement. 5 distinguishing characteristics: joint cavity, articular cartilage, synovial membrane, synovial fluid, and fibrous capsule. Most vulnerable to injury.
 Types
• Uniaxial – one motion around a single axis in one plane
o Hinge – elbow joint
o Pivot – atlantoaxial joint
• Biaxial – movement in two planes through convex/concave surfaces
o Condyloid – MCP joint of finger
o Saddle – CMC joint of thumb
• Multi-axial – movement in three planes
o Plane (gliding) – carpal joints
o Ball and socket – hip joint

Question 4

Free nerve endings

Answer 4

 Location: joint capsule, ligaments, synovium, fat pads
 Sensitivity: One type sensitive to non-noxious mechanical stress and other type sensitive to noxious mechanical or biomechanical stimuli
 Primary distribution: all joints

Question 5

Golgi ligament endings

Answer 5

 Location: ligaments
 Sensitivity: tension or stretch on ligaments
 Primary distribution: Majority of joints

Question 6

Golgi-Mazzoni Corpuscles

Answer 6

 Location: joint capsule
 Sensitivity: compression of joint capsule
 Primary distribution: knee joint, joint capsule

Question 7

Pacinian Corpuscles

Answer 7

 Location: Fibrous layer of joint capsule
 Sensitivity: Vibration, acceleration, high velocity changes in joint position
 Primary distribution: All joints

Question 8

Ruffini Endings

Answer 8

 Location: Fibrous layer of joint capsule
 Sensitivity: Stretching of joint capsule, amplitude and velocity of joint position
 Primary distribution: Greater density in proximal joints