Chapter 4 Arthrokinematics
Osteokinematic Motion―End Feel Normal Bony Soft tissue stretch Soft tissue approximation Abnormal Bony Boggy Muscle spasm Empty Springy block Osteokinematics = classical or physiological motion; End feels – quality of motion; Bony = hard; Soft Tissue Stretch = firm Soft Tissue Approximation = soft Abnormal: boggy – acute; edema muscle spasm – reflexive muscle guarding springy block – cartilage involvement
Arthrokinematic Motion Accessory motion terminology Component movements Joint play Joint mobilization Joint manipulation Joint surface shape Ovoid joint Sellar (saddle-shaped) joint Arthrokinematic Motion – joint surface motion Component Movements – motions that accompany active motions but are not under voluntary control; scapula upward rotation with shoulder flex Joint Play – spin, glide, roll Ovoid – convex/concave Sellar – both surfaces are conves & concave; CMC joint of thumb
Types of Arthrokinematic Motion Roll Glide or slide Spin Roll – new points contact new points Glide or Slide – linear; one point on one surface contacts new points on another surface Spin – rotation of moveable surface on fixed adjacent surface
Convex-Concave Rule Concave joint surface Convex joint surface Moves in the same direction as the body segment’s motion Convex joint surface Moves in the opposite direction of the body segment’s movement
Joint Surface Positions (Joint Congruency) When a joint is congruent, the joint surfaces Have maximum contact with each other Are tightly compressed Are difficult to distract Are in the close-packed position See Table 4-1 page 35
Joint Surface Positions (Joint Congruency) In all other positions, the joint surfaces are incongruent Open-packed or loose-packed position Resting position
Accessory Motion Forces Traction Approximation Shear Bending Rotary Joint Play; Requires External Force Traction – distraction/tension; mobility Approximation/Compression – stability Shear – glide Bending – compression on concave side & distraction on convex side Rotary – twisting force