Nerve endings of the wrist joint: A preliminary report of the dorsal radiocarpal ligament

Abstract

As part of an investigation of the articular nerve ending populations in the wrist joint capsule associated with the anterior and posterior interosseous nerves, this study addresses the nerve ending population in the dorsal radiocarpal ligament. The ligaments were harvested from four wrists of two fresh cadavers within 12 h of death. Tissues were fixed, cryostat sectioned, and processed for fluorescence immunohistochemistry using antibody to protein gene product 9.5 (PGP 9.5), a general or pan neuronal marker, and a secondary antibody conjugated to a fluorescent tag (Alexa Fluor 488). The sections were evaluated with a confocal laser microscope and an image analyzer. Labeled nerve endings were mapped, measured, and categorized. Type I (Ruffini-like ending), Type III (Golgi-like tendon organ) and Type IV (noncorpuscular) nerve endings could be identified in all four DRC ligaments, with Types I and IV dominating. These receptors were distributed primarily over the superficial two thirds of the ligament (>80%), and near the bony attachments (>70%). The dorsal radiocarpal ligament has a rich sensory innervation from the posterior interosseous nerve terminating in nerve endings located in the superficial two-thirds of the ligaments, primarily near bony attachment sites. ß

Immunohistochemical Analysis of Wrist Ligament Innervation in Relation to Their Structural Composition

“…The latter topographic observation correlates to previous observations on general ligament histology and function, 6 as well as the findings in a recent publication on the distribution of mechanoreceptors in the human DRC. 7 The epifascicular region of ligaments previously has been referred to as the epiligamentous sheath, 8 denoting a structure surrounding, and not part of, a ligament. This area, however, has been proposed to be of importance for ligament nutrition and protection, as well as for providing support to the neurovascular bundles in the ligament.…”

Effect of Partial Wrist Denervation on Wrist Kinesthesia: Wrist Denervation Does Not Impair Proprioception

“…12 The roles of these nerve endings remain to be specified. However, our results suggest that these neural endings might have roles other than giving information about joint position.…”

“…3 The anatomic study of the wrist's innervation performed by Lin et al 12 showed that the AIN and PIN are responsible for the innervation of three-quarters of the wrist capsule. Therefore, the aim of this study was to determine whether sectioning the AIN and the PIN impairs kinesthesia.…”

Unusual Compression Neuropathies of the Forearm, Part I: Radial Nerve

“…Although the PIN is classically thought of as being a "motor-only" nerve, the PIN also carries unmyelinated (group IV) afferent fibers from the wrist capsule as well as small myelinated (group IIA) afferent fibers from the muscles along its distribution. 73 Unmyelinated group IV fibers from muscles (designated as C-fibers when of cutaneous origin) have long been associated with nociception and pain. Whereas many group IV fibers respond to noxious stimuli, others have been shown to be excited by relatively innocuous mechanical stimuli.…”