Morphological study of mechanoreceptors in collateral ligaments of the ankle joint

Xiaochuan Wu,Shengbin Bai,Cuihuan Zheng,Shixiong Zhou,Weidong Song

doi:10.1186/s13018-015-0215-7

Abstract

BackgroundThe aim of this study was to analyze the pattern and types of sensory nerve endings in ankle collateral ligaments using histological techniques, in order to observe the morphology and distribution of mechanoreceptors in the collateral ligaments of cadaver ankle joint, and to provide the morphological evidence for the role of the ligament in joint sensory function.MethodsTwelve lateral collateral ligaments including anterior talofibular ligament (ATFL; n = 6), posterior talofibular ligament (PTFL; n = 6), and calcaneofibular ligament (CFL; n = 6) were harvested from six fresh frozen cadavers. The ligaments were embedded in paraffin, sectioned at 4 μm, and then stained using a modified gold-chloride staining methods. The collateral ligament was divided into three segments: proximal, middle, and distal segments. Fifty-four ATFL slides, 90 PTFL slides, and 108 CFL slides were analyzed. Mechanoreceptors were classified based on Freemen and Wyke’s classification. Mechanoreceptor distribution was analyzed statistically. One-way ANOVA (postHoc LSD) was used for statistical analysis.ResultsAll the four typical types of nerve endings (the Ruffini corpuscles, Pacinian corpuscles, Golgi tendon organs, and free nerve endings) were identified in these ligaments. Pacinian corpuscles were the predominant in all four complexes. More mechanoreceptors were found in synovial membrane near both ends of the ligaments attached to the bone. No statistical differences were found in the amount of mechanoreceptors among distal, middle, and proximal parts of the ligaments.ConclusionsThe four typical types of mechanoreceptors were all identified in the collateral ligaments of the human ankle. Pacinian corpuscles were the predominant in all four complexes. This indicates that the main function of ankle collateral ligaments is to sense joint speeds in motions.

Highlights

Ankles are the most important large joints of shock absorption and load bearing
As the lateral ligaments are weaker than the medial ligament and the inversion muscle group is stronger than the eversion muscle group, the lateral ligaments are likely to be injured, taking up about 85 % of the ankle sprain [2]
This study focused on the morphological structure and distribution of the proprioceptive mechanoreceptors in the lateral ligaments of the human ankle

Summary

Introduction

The ankle sprain is one of the most common sports injuries in clinic [1]. It happens when stepping on uneven ground or on some object, with the movement of excessive plantar flexion and ankle inversion. In addition to biomechanical function, the collateral ligaments contribute to the proprioceptive function [3, 4]. Once injured, it can disturb the proprioceptive information input and the coordination control of the nerve center to the complex of the joint nerve muscle, leading to functional instability of the ankle [5]. The aim of this study was to analyze the pattern and types of sensory nerve endings in ankle collateral ligaments using histological techniques, in order to observe the morphology and distribution of mechanoreceptors in the collateral ligaments of cadaver ankle joint, and to provide the morphological evidence for the role of the ligament in joint sensory function

Objectives

Methods

Conclusion