4. Biological basics of movements, passive motion system, types of joints

Passive motion system

Joints, bones, ligaments, capsules

Passive motion system tasks

Flexibility and rigidity
Protection of internal organs and soft tissues
Blood cell formation
Lightweight but stronger than concrete
Can regenerate itself

Synarthroses (skull)

Sutura, gomphosis (teeth), syndesmosis
Synchondrosis
Synostosis

Diarthroses: Uniaxial (one plane)

Hinge joints
Pivot joints

Diarthroses: Biaxial (two planes)

Condyloid (MCP, Radiocarpea)
Saddle joints

Diarthroses: Multiaxial

Plane
Ball and socket

Diarthroses

There is space between articular surfaces

Syndesmosis

Two joint surfaces joined together with ligaments (distal tibio-fibular joint)

Synchondrosis

Surfaces joined together with cartilage (sternum)

Synostosis

Joints held together with bony pieces (sacrum)

Body composition

Ratio of fat, muscle, bone, water
If weight and body composition is optimal, loading on joint surfaces is also optimal

Position of Centre of gravity

Anteriorly from S2.
If gravity line and COG is shifted from the physiological position, there will be imbalance in the muscles, some muscles will be overused, elongated, weak.
Loading on joint surfaces is large

Cartilage

On joint surfaces. Pain free movements and joint surfaces can move with each other

Cartilage pathological process

Arthritis
Cartilage is destroyed. At the final stage, boney surfaces move over each other painfully

Synovial fluid

Small amount of fluid in the joint for mobility

Synovial fluid pathological process

Liquid will be larger, causing compression and pain.

Capsule

Can cover around joint surfaces, stabilizes joint.

Capsule pathological process

Compression and irritative inflammation

Ligaments

Static stabilizers of joint

Discus, meniscus

Reduce external forces

Pathological process: Disc hernia, menisci ruptures

Bursa

Liquid filled surface near the joint, stabilizers, reduces external forces

Bursa Pathological processes

Bursitis, inflammation of the joint, ROM decreased, muscles are tensed

Tendon sheet

Structure in which tendons run through. Protects tendons

Tendon sheet pathological process

Inflammation & Stenosis
Not enough space for tendon, causing them to shift leading to improper function

Labrum

Found in hip & glenohumeral joint, allowing cavity to be deeper. Stabilizes joint

Labrum pathological process

Inflammation and adhesion, cannot mobilize joint

Ovoid type

Joint surfaces have the save convexity and concavity in all motions and every plane (glenohumeral joint)

Sellar type

Joint surfaces can be in concavity in one type of motion, and convexity in another. Joint surfaces have concave and convex parts (saddle joint, sternoclavicular joint)

Open kinematic chain

Fixed proximal, moving distal

Close kinematic chain

Moving proximal, fixed distal (complex, but safer)

Arthrokinematics

Rolling
Sliding
Spinning
Compression
Distraction

Osteokinematic motion

Visible motion of joint with rotatory component

Arthrokinematic motion

Non-visible motion between joint surfaces with translatory component

Joint play in closed pack position

Ligaments are loose, large space between surfaces.

Joint play is harmonic and optimal

Joint play in open pack position

Small space between joint surfaces, no joint play

Concave-convex rule (Kaltenborn): Concave

Only true for sliding movements

If concave joint surfaces moves on the fixed convex surface, the directions of the osteokinematic movement and the arthrokinematics sliding are the same

(Radius and ulna moving on humerus, tibia moving on femur)

Concave-convex rule (Kaltenborn): Convex

If convex joint surfaces moves on fixed concave surfaces, the directions of the osteokinematic movement and the arthrokinematic sliding are opposite

(Knee in closed kinematic chain, femoral condyle moves on tibia)

Functional ROM

Can be made actively by patient

Anatomical ROM

Larger ROM with passive support