343
Views
13
CrossRef citations to date
0
Altmetric
Original Articles

Dynamic Pinch Tolerance of the Phalanges and Interphalangeal Joints

, &
Pages 83-88 | Received 24 Aug 2007, Accepted 21 Sep 2007, Published online: 12 Mar 2008
 

Abstract

Objectives. This article presents force and displacement tolerances for pinch loading of the bones and joints of the digits.

Methods. Dynamic (54 mm/s) pinch loading was applied in a dorsal-palmar direction to all digits (fingers and thumb) on matched pairs of hands from 8 adult human cadavers. Opposed 3.1-mm thick, 1.0-mm radius of curvature aluminum pinching surfaces were used to represent the geometry of moving surfaces in an automobile, such as doors, lift gates, or window edges. Injury timing was determined using acoustic sensors. The applied force and the distance between the pinching surfaces at the time of an acoustic burst were recorded.

Results. The force tolerance ranged from 245 N for the distal phalanx of the fifth digit (little finger) to 1,155 N for the middle phalanx of the second digit (index finger), with a general trend toward increasing force tolerance for more proximal anatomical structures. The distance between pinching surfaces (gap) at the time of injury ranged from 4.5 mm for the distal interphalangeal joint of the fifth digit to 9.1 mm for the proximal phalanx of the third digit (middle finger). Orthopedic trauma found during necropsy of the test specimens included tuft fractures, transverse fractures, cortical crush injuries, a longitudinal fracture, and tendon injuries.

Conclusions. A value of approximately 35% of the initial dorsal-palmar dimension of the phalanx is reasonably representative of the gap tolerance for all digits and loading sites considered here. Although additional testing is required to quantify variability in tolerance, the tests here indicate that moving surfaces having geometry similar to that considered here would not be expected to injure a digit if the opposing surfaces come no closer together than 35% of the digit's dorsal-palmar dimension.

ACKNOWLEDGMENTS

The authors would like to thank Jason Forman and Jason Mattice for their assistance in the design, preparation, and execution of the tests, as well as Dr. Carl Heine for his expertise in injury identification and classification. Financial support from Delphi Corporation is also acknowledged, although the findings of the study are those of the authors alone.

Notes

∗1. Wrist circumference (styloid to styloid).

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

Issue Purchase

  • 30 days online access to complete issue
  • Article PDFs can be downloaded
  • Article PDFs can be printed
USD 331.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.