Understanding Arthrokinematics & Joint Motion

1. Chapter 4 Arthrokinematics

2. Points to Remember • Normal end feel can be described as bony, soft tissue stretch, or soft tissue approximation • Abnormal end feel can be described as bony, boggy, empty, springy block, or muscle spasm • Types of arthrokinematic motion and roll, glide or spin. • According to the concave - convex rule, concave joint surface move in the same direction as the joint or body segment’s motion, while convex surfaces move in the opposite direction as the joint in motion • When a joint is congruent , it is in the close-packed (tight) position. When the joint is incongruent, it is in the open-packed (loose) position.

3. Osteokinematic Motion • End Feel: a subjective assesment of a quality of the feel when slight pressure is applied at the end of the joint • Normal bony end feel is characterized by a hard & abrupt limit to passive joint motion • Normal soft tissue stretch : a firm sensation that has slight give when the joint is taken to end ROM • Soft tissue approximation: when muscle bulk is compressed giving a soft end feel • Abnormal Boney feel – a sudden hard stop usually felt well before the end of normal ROM • Muscle Spasm – reflexive muscle guarding motion • Empty end feel – movement produces considerable pain • Springy Block - a rebounf movement is felt at the end of the ROM

4. Accessory Motion Terminology • Component Movement – are motions that accompany active motion but are under voluntary control • Joint Play Movements – passive movements between joint surface done by passing applying external force • Joint Mobilization – a passive oscillatory motion or

5. Convex- Concave Rule • Important: knowing that a joint surface is concave or convex is important because shape determines motion • Concave-Convex Rule: describes how the differences in shape of bone ends require joint surfaces to move in a specific way during joint movement • A concave joint surface will move on a fixed convex surface in the same direction the body segment is moving • The Concave joints surface moves in the same direction as the body segment motion • The Convex joint surface moves in the opposite direction as the body segment motion

6. Accessory Motion • Traction – occurs when external force exerted on a joint, causing the joint surface to pull apart • Approximation – occurs when external force is extended on a joint, causing the joint surface to be pushed close together • Shear – occurs when panedel to the surface, shear force results in a glide motion at the joint • Bending – occurs when an other- than – vertical force is applied, resulting in compression of the concave side and distraction on the convex side

7. Types of Arthrokinematic Motion • Roll: rolling of one joint surface to another • Glide/ Slide: linear movements of the joint surface to other joints • Spin: Rotation of a moveable joint surface on a fixed curve

8. Chapter 3 Articular System

9. Types of Joints • Joint – a connection between 2 bones to allow motion

10. Types of Joints • Fibrous Joint – has a thin layer of fibrous periosteum between the 2 bones, such as in the suture of the skull • Synarthrosis: the ends of the bones are shaped to allow them to interlock. This joint has no motion between the bones, the purpose is to provide shape and strength • Syndesmosis/Ligaments: ligaments intercross membranes holding the joints together. Twisting or stretching movement • Gomphosis: “ bolting together” joint occurs between a tooth and wall of its dental socket in the mandible maxilla

11. Types of Joints • Cartilaginous Joint/ Amphiarthrodial : Small amount of motion such as bonding or twisting, and some compression

12. Types of Joints • Synovial Joint/ Diarthrodial • allow free motion • not as stable • Joints: • Nonaxial: glides; “Plane” • Uniaxial Joint: 1 plane around 1 axis; “Hinge” or “Pivot” • Biaxial Joint : 2 different directions for 1 joint; “Condyloid” or “Saddle” • Trixial Joint : occurs in 3 axes; “Ball and Socket” • Shapes of Joints • Pivot Joint: pivot motion is a transverse plane around the longitudinal axis • Condyloid Joint: bidirectional motion • Saddle Joint : fits together like a horseback rider on a saddle

13. Types of Joints

14. Degrees of Freedom • Uniaxial jt has motion around 1 axis and in 1 plane = 1 degree of freedom • Biaxial jt = 2 degrees of freedom • Triaxial jt = 3 degrees of freedom • 3 degrees of freedom is the max # an individual jt can have • How many degrees of freedom does the arm have?

15. Planes and Axes • Planes of action – fixed lines of reference along which the body is divided • Sagital Line - passes through the body into the right and left parts • Frontal Plane (Coronal Plane) – Passes through the body from side to side and divides the body from side to side and divides the body into front and back parts • Transverse Plane (Horizontal Plane) – Passes through the body horizontally and divides the body into equal parts • Cardinal Plane – whenever a plane passes through the body horizontally and divides the body into top and bottom parts • Center of Gravity – the point where the three cardinal planes intersect each other • Sagital Axis – a point that runs through a joint from side to side • Vertical Axis (Longitudinal Axis) – runs through a joint from top to bottom

16. Joint Structure • Bones – articulate the amount and direction of motion • Ligaments – connective tissue to help control joint motion • Capsule – protects joints and bone surfaces • Synovial Membrane- a vascular connective tissue that secretes synovial fluid • Synovial Fluid – a thick, clear fluid, that lubricants the articular cartilage • Articular Cartilage – covers the ends of opposing bones. Provides blood. • Fibrocartilage – Shock absorber weight banning joints like knee • Elastic Cartilage – Help maintain a structure's shape • Tendon – connect muscle to bone • Bursae - padlike sacs in joints

17. Levers • Limbs are like machines • The action of a muscle pulling on a bone often works like a type of simple machine called a LEVER. • 1st CLASS LEVER: the weight and force are on the opposite sides of the fulcrum/axis (the fulcrum/axis is the middle) • 2nd CLASS LEVER: the load/weight is between the fulcrum and the force (the load/weight is in the middle) • 3rd CLASS LEVER: the force in between the fulcrum and the load (the force is in the middle)

18. Common Pathological Terms • Dislocation: Complete separation of the 2 articular surface of a joint • Subluxation: Partial dislocation of a joint, usually occurs over a period of time (degenerative arthritis) • Osteoarthritis: type of arthritis that is caused by the breakdown and eventual loss of the cartilage of one of the most joints • Sprains: partial or complete tearing of the ligament fibers • Strain: overstretching the muscle fibers as with sprains and strains

19. Common Pathological Terms • Tendonitis – is an inflammation of the tendon • Synovities – is an inflammation of the synovial membrane • Tendosynovitis- an inflammation of the tendon sheath and is often caused by repetitive use • Bursitis – an inflammation of the bursa • Capsulitis – and inflammation of the joint capsule

20. Did you know turtles can breathe through their butts?(: