Polygraph Glossary Physiology

phalanx

Definition

A phalanx (plural: phalanges) is any bone of the fingers or toes. In PDD, electrodermal sensors are typically attached to the distal phalanx (fingertip) and the Plethysmograph sensor is placed on another finger.

What Is a Phalanx?

A phalanx (plural: phalanges) is any bone of the fingers or toes. In PDD, electrodermal sensors are typically attached to the distal phalanx (fingertip) and the Plethysmograph sensor is placed on another finger.

Historical and Modern Context

The evolution of polygraph instrumentation — from early mechanical devices to modern digital systems — reflects the broader advancement of the field from subjective interpretation to validated, structured test data analysis. Modern instruments from manufacturers such as Lafayette, Limestone, and Stoelting incorporate multiple measurement channels, digital recording, and computerised scoring capabilities.

Professional Context

This concept forms part of the knowledge base expected of qualified forensic psychophysiologists. Training at APA-accredited schools covers the theoretical foundations, practical applications, and research evidence underlying all aspects of polygraph methodology. Ongoing continuing education ensures practitioners stay current with developments in the field.

For comprehensive information on polygraph terminology and methodology, explore the complete polygraph glossary or visit the Polygraph Examiner Hub.

Cross-references

More physiology terms in this glossary

Vasoconstriction A narrowing of blood vessels resulting in reduced blood flow and decreased pulse amplitude, measured by the cardio cu... extrasystolic beat An extrasystolic beat is an older term for a premature ventricular contraction (PVC) — a heartbeat occurring outside ... Eccrine Sweat Glands Sweat glands found primarily on the palms, fingertips, and soles of the feet that are innervated by the sympathetic n... eupnea Eupnea is normal, quiet breathing at rest. In polygraph testing, eupnea represents the baseline respiratory pattern a... tachycardia Tachycardia is an abnormally rapid heartbeat (>100 bpm). In PDD, tachycardia may signal pharmaceutical Countermeas... respiratory cycle time Respiratory cycle time (RCT) is a diagnostic feature calculated by comparing the breathing cycle duration before and ...

Need a lie detector test?

Book with an examiner trained to APA standards at one of our 140+ locations nationwide.

Book a test Full glossary A–Z

Professional resource Polygraph Examiner Hub Training programs, APA documents, research database, glossary, and professional tools — the complete resource center for polygraph examiners and students.