0
Research Papers

Carpal Tunnel Expansion by Palmarly Directed Forces to the Transverse Carpal Ligament

[+] Author and Article Information
Zong-Ming Li1

Department of Orthopaedic Surgery, Department of Bioengineering, and Department of Occupational Therapy, Hand Research Laboratory, University of Pittsburgh, Pittsburgh, PA 15213zmli@pitt.edu

Jie Tang, Matthew Chakan, Rodrigo Kaz

Department of Orthopaedic Surgery, Department of Bioengineering, and Department of Occupational Therapy, Hand Research Laboratory, University of Pittsburgh, Pittsburgh, PA 15213

1

Corresponding author. Also at 210 Lothrop Street, E1641 BST, Pittsburgh, PA 15213.

J Biomech Eng 131(8), 081011 (Jul 09, 2009) (6 pages) doi:10.1115/1.3148469 History: Received September 12, 2008; Revised March 09, 2009; Published July 09, 2009

This study investigated the expansion of the carpal tunnel resulting from the application of palmarly directed forces to the transverse carpal ligament (TCL) from inside the carpal tunnel. Ten fresh-frozen cadaveric hands were dissected to evacuate the carpal tunnel, and thus to expose the TCL. A custom lever device was built to apply forces, ranging from 10 N to 200 N, to the TCL. Without force application, the carpal tunnel area was 148.4±36.8mm2. The force application caused the TCL to form arches with an increase in cross-sectional areas of 33.3±5.6mm2 at 10 N and 48.7±11.4mm2 at 200 N, representing respective increases of 22.4% and 32.8% relative to the initial carpal tunnel area. The TCL length remained constant under the applied forces. It was found that the TCL arch formation was due to the narrowing of the arch width, which resulted from the migration of the bony insertion sites of the TCL. A geometrical model of the carpal tunnel was then developed to elucidate the relationships among the arch width, TCL length, arch height, and arch area. The model illustrated the effectiveness of carpal tunnel expansion by TCL elongation or arch width narrowing.

FIGURES IN THIS ARTICLE
<>
Copyright © 2009 by American Society of Mechanical Engineers
Topics: Force , Arches , Tunnels , Elongation
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Cadaveric preparation of the carpal tunnel and TCL viewed (a) palmarly and (b) proximally

Grahic Jump Location
Figure 2

The custom lever device used to apply forces to the TCL

Grahic Jump Location
Figure 3

Digitization of the TCL surface while the TCL was loaded with the lever device

Grahic Jump Location
Figure 4

A schematic of the cross-sectional area of the carpal tunnel is composed of two parts: the baseline area formed by the carpal bones with an assumed flat TCL (A1) and the area formed by the TCL arch (A2)

Grahic Jump Location
Figure 6

A representative plot of TCL arch curves in the transverse plane. The curves move progressively upward with increasing forces. The circles denote edge points of the TCL.

Grahic Jump Location
Figure 7

Changes in (a) arch height, (b) arch area, (c) arch width, and (d) TCL length with increasing forces

Grahic Jump Location
Figure 8

Geometric representation of the cross section of the carpal tunnel. (a) Initial carpal tunnel without an arch. (b) Arch formation by the elongation of the TCL with a constant arch width. (c) Arch formation by the arch width narrowing assuming a constant TCL length. The enclosed area by the dashed curve and line in Fig. 8 represents the initial carpal tunnel.

Grahic Jump Location
Figure 9

(a) Arch height and (b) arch area due to TCL lengthening (Δl) or arch width narrowing (Δa)

Grahic Jump Location
Figure 10

The changes in (a) arch height, (b) arch area, and (c) total area with the change in arch width (Δa)

Grahic Jump Location
Figure 5

Representative surface plots of a TCL without force application (the “flat” surface) and the TCL under a 200 N force (the arched surface)

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In