Fiber orientation of the transverse carpal ligament

Abstract

The transverse carpal ligament is the volar roof of the carpal tunnel. Gross observation shows that the ligament appears to have fibers that roughly orient in the transverse direction. A closer anatomical examination shows that the ligament also has oblique fibers. Knowledge of the fiber orientation of the transverse carpal ligament is valuable for further understanding the ligament's role in regulating the structural function of the carpal tunnel. The purpose of this study is to quantify collagen fiber orientation within the transverse carpal ligament using the small angle light scattering technique. Eight transverse carpal ligament samples from cadaver hands were used in this study. Individual 20 μm sections were cut evenly along the thickness of the transverse carpal ligament. Sections of three thickness levels (25%, 50%, and 75% from the volar surface) were collected for each transverse carpal ligament. Fibers were grouped in the following orientation ranges: transverse, longitudinal, oblique in the pisiform-trapezium (PT), and oblique in the scaphoid-hamate (SH) directions. In analyzing the fiber percentages, the orientation types for the different thickness levels of the ligament showed that the transverse fibers were the most prominent (>60.7%) followed by the PT oblique (18.6%), SH oblique (13.0%), and longitudinal (8.6%) fibers.

Volar/dorsal compressive mechanical behavior of the transverse carpal ligament

“…The center location was defined as the midpoint between the hamate and trapezium landmarks in the radial/ulnar direction, and half of the specimen’s proximal/distal width at that location. A fiber axis corresponding to the TCL’s preferential collagen orientation (Prantil et al, 2010) was defined by a line connecting the midpoint between the hamate and pisiform landmarks with the midpoint between the trapezium and scaphoid landmarks (Figure 1b). …”

Tensile properties of the transverse carpal ligament and carpal tunnel complex

“…The TCL has been investigated morphologically (Pacek et al, 2010a) and its collagen fibre orientation has been characterized (Prantil et al, 2012). So far although these studies have provided an understanding of the TCL composition and behaviour, more research is still necessary to fully understand the biomechanical properties of the TCL.…”

Constitutive mechanical properties of carpal tunnel soft tissue structures

“…Although the PMMA potting procedure was used to apply the tensile load parallel to the preferential orientation of collagen in the tissue (Prantil et al 2010), the spindle shape of the TCL likely caused unequal tensioning across the proximal/distal width of the ligament. More specifically, the central region of the ligament appeared more tensioned than the proximal and distal edges.…”

“…The TCL center location was defined as the point halfway between the hamate and trapezium landmarks in the radial/ulnar direction, and half of the specimen's proximal/distal width at that location. Next, a fiber axis corresponding to the TCL's preferential collagen orientation (Prantil et al 2010) was defined by defining a line connecting the midpoint between the hamate and pisiform landmarks, and the midpoint between the trapezium and scaphoid landmarks ( Figure 32).…”

“…Many studies have evaluated the functional properties of the carpal arch to better understand the use of TCL transection as a treatment option for CTS. In these studies, the TCL was found to contribute somewhat to the stability of the carpal tunnel during the application of radial/ulnar loads (Xiu et al, 2010;Tengrootenhuysen et al, 2009;Guo et al, 2008). However, when intact carpal tunnels were compressed in the dorso/palmar direction, the TCL was not found to play an essential role in maintaining carpal arch stability (Garcia-Elias et al 1989).…”