Arthrokinematics/Osteokinematics

Question 1

Small Joint Motion - Spinning

Answer 1

• no jt perfectly spins, there is always some degree of glide or roll
• with pure spinning, the axis of rotation does not change positions
• i.e. ER/IR (like car stuck in ice and tires just spinning)

Question 2

Small Joint Motion - Translation

Answer 2

• aka GLIDING
• i.e. car is sliding on ice w/o tires moving
• too much translation is a bad thing for any joint as it stretches the ligaments and jt capsule
• abnormal movement of the jt usually increases the amount of jt translation

Question 3

Small Joint Motion - Rolling

Answer 3

• rolling = jt distraction
• typical in knee joint: knee joint glides, rolls, and spins.
• rolling in shoulder joint is a problem
• all joints have all 3 types of movements occuring, but excessive rolling or translation can be a problem.

Question 4

Plane Joint

Answer 4

• only movement allowed is a translation (sliding) of one bone on the other
• one flat surface sliding with another flat surface
• don’t afford much rotation in a single joint, but if you put enough plane joints together (i.e. intercarpal/intertarsal) you get a small degree of motion
• referred to as “non-axial”
• (i.e. carpal bones [best example}; and vertebrae]

Question 5

Pivot Joint

Answer 5

• one bone (or fibrous attachment) completely surrounds another bone
• uniaxial, single plane. 2 primary movements.
• good congruence
• i.e. proximal radioulnar joint; C1/C2 vertebral joint

Question 6

Hinge Joint

Answer 6

• uniaxial, single plane. 2 primary movements.
• “claw” of one bone hooks around cylindrical part of another bone
• good congruence
• i.e. humeroulnar joint; ankle joint

Question 7

Condyloid/Ellipsoid Joint

Answer 7

• biaxial, biplanar. 4 primary movements
• i.e. wrist and knee
• wrist (uln/rad deviation; flex/ext)
• knee (flex/ext; IR/ER w/ screw home mech)

Question 8

Ball & Socket Joint

Answer 8

• triaxial, tri planar. 6 primary movements
• poor congruence (shoulder) (hip is actually good)
• shoulder: greatest mobility in body.

Question 9

FLEXION

Answer 9

reference angle decreases

Question 10

EXTENSION

Answer 10

reference angle increases

Question 11

HYPEREXTENSION

Answer 11

reference angle goes beyond 180 degrees

Question 12

ABDUCTION

Answer 12

move away from anatomical position

Question 13

ADDUCTION

Answer 13

move toward anatomical position

Question 14

Axis of Rotation

Answer 14

Imaginary rod, passing through “center” of joint perpindicular to the plane of movement