title: Morphological study of mechanoreceptors in collateral ligaments of the ankle joint.
abstract: BACKGROUND
  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.
  
  
  METHODS
  Twelve 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.
  
  
  RESULTS
  All 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.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Department of Orthopaedics, Sanxiang Hospital, Zhongshan, Guangdong Province, 528463, China. xiaochuanwu37@yeah.net.
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Orthopaedics, Sun Yat-sen Memorial Hospital, 107 Riverside Road, Guangzhou, Guangdong Province, 510120, China. weidongsong137@yeah.net.
authors.forename: Weidong
authors.initials: W
authors.lastname: Song
authors.affiliation: Intensive Care Unit, Sanxiang Hospital, Zhongshan, Guangdong Province, 528463, China. cuihuanzheng156@yeah.net.
authors.forename: Cuihuan
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Department of Histology and Embryology, Guangdong Medical College, Zhanjiang, Guangdong Province, 523000, China. shixiongzhou26@yeah.net.
authors.forename: Shixiong
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Histology and Embryology, Xinjiang Medical University, Urumqi, Xinjiang Province, 830054, China. shengbinbai17@yeah.net.
authors.forename: Shengbin
authors.initials: S
authors.lastname: Bai
mesh_terms: D000328:Adult; D005260:Female; D017612:Gold Compounds; D006801:Humans; D017844:Lateral Ligament, Ankle / Q000166:cytology*; D008297:Male; D008465:Mechanoreceptors / Q000166:cytology*; D008875:Middle Aged; D055815:Young Adult
chemical_list: D017612:Gold Compounds; C038016:gold chloride