Biomechanics of Manual Therapy

**Manual Therapy techniques should be used for:**

1. Increase ROM
2. Modulate pain
3. Address joint dysfunction

**Some factors that may alter joint mechanics:**

1. Disease (DJD, inflammation)
2. Periods of immobilization (capsule shortening, adhesions)
3. Anatomical differences/ imbalances/ subluxations
4. Acute Injury
5. Fatigue

## Terminology

### **Mobilization**

A passive joint movement whose purpose is to increaes ROM or decrease pain. Is is applied to joints and related soft tissues at varying speeds & amplitues using *physiologic* and *accessory motions*. The force used is light enough so that the patient can stop the movement.

*Mobilization with Movement (MWM) -*Concurrent application of a sustained accessory mobilization applied by a clinician & an active physiologic movement to end range applied by the patient. \*Should be
 applied in the pain free direction
Effects of Mobilization

* *Neurophysiological* - stimulate mechanoreceptors to reduce pain, affect muscle spasm and guarding, increase awareness and position of motion (increased afferent information)
* *Nutritional* - distraction or small gliding movements causes synovial fluid movement to increase nutrient exchange due to joint swelling and immobilization
* *Mechanical* - improve mobility of hypomobile joints (adhesions and thickened CT from immobilization) & to maintain extensibility & tensile strength of articular tissues

*More information can be found on the Mobilizations Introduction page.*

### **Manipulation**

A passive joint movement for increasing joint mobility. Incorporates a sudden forceful thrust that is beyind the patient's control.

### **Arthrokinematics**

The study of joint mechanics; the movement of one articular surface on another without regard to the movement of the bone or the forces producing that movement. In the periphery, movement is named after the direction of the distal bone whereas in the spine, movement in named after the superior vertebra.

* *Slide -*The linear displacement of one articular surface across another. When applied passively, it is called a *glide*

* *Roll -*A series of points on one articulating surface come into contact with a series of point on the other surface. Ie. movement like a rocking chair. Rolling occurs in the direction of movement, usually on incongruent surfaces in combination with sliding or spinning.

* *Spin -*Occurs when a long bone rotates around a stationary longitudinal axis

* *Compresssion - D*ecrease the space between two joint surfaces, adds stability to a joint, normal reaction to a muscle contraction

* *Distraction -*Articular surfaces pulled apart, usually used in combination with joint mobilization to increase the stretch of capsule.

### **Osteokinematics**

The study and measurement of motion of a bone in space. Study of movement of a bone around its mechanical axis without regard to the motion occuring at the joint surfaces, or the forces producing it.

Closed pack position - position with the greatest amount of congruency between joint surfaces (maximum taughtness of major ligaments. Position to test ligament stability, not an ideal position for mobilization/ manipulation (minimal joint space, tight soft tissues, could damage the joint)
Loose pack position - resting position, periarticular tissues are most lax, greatest amount of accessory movement possible.
### **Physiology and Accessory Joint movements**

*Physiologic Joint movement*- motion that a person can actively produce on their own, from concentric or eccentric contraction. Bones moving about an axis through flexion, extension, adduction, abduction, or rotation.

* *Passive Physiologic Movement (PPM)* - Osteokinematic motion produced by an individual or passively by the therapist.

* *Passive Physiological InterVertebral Motion (PPIVM)* - passive physiologic motion between adjacent vertebrae

Accessory Joint movement- movement between joint surfaces that cannot be produced voluntarily; it is a movement that occurs with passive physiological motion (necessary for full range physiologic motion to occur). Occurs perpendicular to the asix of movement and parrallel to the plane of the joint (parallel to the joint surfaces) & ligaments and joint capsule are involved in motion.

* Passive Accesssory Movement (PAM) - Arthrokinematic motion (non-physiologic) produced by an individual or passively by the therapist

* Passive Accessory InterVetebral Motion (PPIVM) - passive accessory motion between adjacent vertebrae

### **Concave Convex Rule**

Concave (female) surfaces are generally rounded inward & away from the joint; convex (male) surface rounded outward & into the joint

* If the concave surface (female) is the moving surface, the direction of the glide is in the same direction as the osteokinematic movement
* if the convex suface (male) is the moving surface, the direction of the glide is in the opposite direction as the osteokinematic movement

### **Classification of Synovial Joints**

Simple (two articular surfaces) vs Complex (>2 articular surface)

Modified (pure joint, entirely concave/convex) vs Unmodified  (slightly more egg shaped than a sphere)

Ovoid joint - A joint in which one surface is entirely convex and the other is entirely concave

Sellar joint - Saddle shaped joint - one joint surface is concave in one direction, but convex in the perpendicular direction (can be modified or unmodified)

## **Components of Musculoskeletal Assessment**

Consists of:

**Scan exam**

* Upper Quadrant scan exam
* Lower Quadrant scan exam

**Biomechanical exam**

*General outline for each exam:*

1. Position tests - looking for symmetry of the joint, evaluated by palpation, test only indicates the resting position (does not tell you about movement)
2. Kinetic tests - bony landmarks are palpated and symmetry of motion is evaluated as the patient actively moves the area, used as an indication that passive motion or stress tests should be done
3. PPMs and PAMs - passively move thorugh the PPMs and PAMs of the joint, looking for quality and quantity of motion (end feel).
4. Stress testing - passive tests of the structural integrity and stability of a joint (used when hypermobility is found during PPMs). Note the amount of displacement, end feel, and reproduction of symptoms

Biomechanical Manuals:

1. Shoulder manual
2. Elbow manual
3. Wrist/Hand manual
4. Cervical Spine manual