PTA 104L Orthopedic Dysfunctions Lab

Instructional Use Statement

The following information is used for instructional purposes for students enrolled in the Physical Therapist Assistant Program at Lane Community College. It is not intended for commercial use or distribution or commercial purposes. It is not intended to serve as medical advice or treatment.

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Introduction and Overview

Traction has a long history of use in physical therapy. Research is positive, neutral, and negative with regards to clinical validity in its ability to draw apart spinal structures. The expense of mechanical traction equipment and traction tables can limit access to this modality. Many manual therapists find their specific joint mobilization techniques and exercise-based approaches just as effective in reducing symptoms as mechanical traction. Similarly many manual therapists will recommend home cervical or lumbar traction units as a component of a home management program. Clinical instruction and clinical emphasis will vary depending on the experience of the therapists, the availability of equipment, and the patient case mix. PTs and PTAs continue to have mechanical traction principles and application as a component of the core, entry level curriculum. PTAs apply and instruct patients in the therapeutic uses of traction. PTAs must also be able to recognize signs and symptoms of an adverse reaction and communicate findings back to the physical therapist.

 Wach and listen to VideoCast on Traction (Approximately 32 minutes)

Specific Areas of Focus

  1. Describe the claims of therapeutic benefit for clinical traction
  2. Calculate traction forces needed to overcome friction
  3. Describe the benefits of using a traction table during treatment
  4. Compare and contrast efficacy of cervical vs. lumbar traction
  5. Select minimum traction poundage for therapeutic effect in the cervical spine
  6. Calculate minimum traction poundage for therapeutic effect in the lumbar spine
  7. Select treatment position based upon target area and goals for intervertebral separation
  8. Analyze and modify application of traction based on the treatment response
  9. Apply cervical and lumbar traction safely and effectively


Drawing apart; pulling

Separation of bones and/or bony segments utilizing a distraction force

Classification of traction

Manual: distraction force is provided by the therapist

Mechanical: distraction force is provided by a machine

Gravitational traction: distraction force is provided by gravity

Opposing force is frictional: resistive force which opposes the traction force

Types of Traction

  1. Autotraction

  2. Cervical traction
  3. Continuous (bed) traction
  4. Elastic traction / Gravity-Assisted traction
  5. Head traction


The features, advantages and disadvantages are reinforced in the Miami Dade PTA Program lecture


Contraindications and Precautions


  1. Spinal infection
  2. RA or other acute inflammatory joint disorder
  3. Osteoporosis
  4. Spinal cancers
  5. Central spinal cord pressure: e.g., tumor, central disc herniation


  1. Joint hypermobility
  2. Acute inflammation
  3. Claustrophobia or anxiety associated with traction
  4. Cardiac or respiratory insufficiency (lumbar and inversion traction); cervical traction risk for internal jugular thrombosis; BP fluctuations
  5. Pregnancy (increased ligamentous laxity and risk for abdominal compression)
  6. Symptoms increase with traction; hx of aggravation with traction
  7. TMJ dysfunction (cervical) if using chin strap


Quiz Yourself

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Calculating Traction Force

Friction effects

Traction pulls are opposed by friction forces. In order for traction forces to effect spinal segments, traction force has to exceed friction force. There is a mathematical relationship between body weight and the amount of friction force from the treatment surface. this is called the "coefficient of static friction".


The relationship of friction between a person and a mat table/treatment table has been found to equal 0.5 or 50% of body weight undergoing lumbar traction. Thoracic belts used in lumbar traction can decrease the amount of friction force, resulting in more net traction pull provided by the machine.

Shortcut method:

Patient body weight * 0.25 = minimum applied traction force to lumbar spine

In the cervical spine, traction forces must be 0.62 or 62% of the weight of the head in order to overcome the friction force from the treatment table.

The mathematical relationships of traction, friction, and the role of straps is reinforced in the linked traction lecture from Miami-Dade PTA Program

Goals of traction


Theory of Therapeutic Effects

Herniation of disc material

Pressure on intradiscal components of the involved disc(s) are reduced. Negative pressure pulls disc material back into the disc, decreasing the size of herniated disc material

Degenerative joint disease

Pressure on facet and foraminal space is temporarily decreased, resulting in nerve compression and decreased nerve root irritation and/or secondary swelling from progressive joint changes

Muscle spasm or guarding

Benefit is due to low load prolonged stretch of surrounding soft tissues of the cervical and lumbar spine

Joint hypomobility

Benefit is due to

  1. moving articular structures on each other
  2. distracting articular structures to free up motion
  3. increase synovial fluid production and nutrition to cartilagenous structures
  4. increase activation of mechanoreceptors to inhibit the pain response

Specific joint mobilization techniques or unilateral manual traction approaches are more specific to increasing segmental joint mobility

Facet Impingement

Benefit is due to decompression of facet capsular structure which can become impinged with compression


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Cervical Traction

Strongest evidence for the benefits of traction is in cervical applications

Benefits of the use of cervical traction is supported in cases of osteoarthritis, cervical radiculopathy, disc herniation, and tension headaches


Physiological effects


Note: there are studies which contradict supposed physiological effects of cervical traction. Remember, evidence-based practice involves utilizing the supporting literature and the patient's goals/response to treatment using the therapist's experience to discriminate the utility of treatment

Mechanical Techniques

Demonstration of home cervical traction device (Approximately 7 minutes)


Angle of pull

Case Demonstration of Mechanical Cervical Traction (Approximately 5 minutes)

Lumbar Traction

Clinically, there is disagreement about the utility and therapeutic effects of lumbar traction. It remains a core component of PT and PTA curriculum, including understanding of its theoretical basis for application ask well as the practical skill of safely applying manual and mechanical traction

Physiological Effects

Note: many of these are unsupported or conflict in the literature.

Mechanical Techniques

Demonstration video of home lumbar tracction unit

Angle of pull

Inversion traction

Form of gravity-assisted traction which uses inversion force to create a lumbar traction force

Amount of force generated = approximately 40% of body weight

Contraindicated for persons with cardiopulmonary or cardiovascular compromise


General Traction Treatment Considerations

Static vs. intermittent

Treatment time



Positional traction


Manual traction

Warning: DO NOT attempt these techniques without direct instructor supervision

Demonstration of cervical manual traction (Approximately 1 minute)

Demonstration of lumbar manual traction (Approximately 3 minutes)

Positioning and Draping

Always position for patient comfort and drape as needed to assure only areas that need to be exposed to perform the techniques are out in the open.



Supplemental Demonstration Videos and Images

Lane Lumbar Traction Unit Demonstration - Chattanooga

Lane Lumbar Traction Set Up Demonstration - Dynatron Unit

Student project - Chattanooga Demonstration Video


You can check your understanding of some key points from traction here. There will be a PNP on traction before lab:

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