title: Cricothyroid Articulation in Elderly Japanese With Special Reference to Morphology of the Synovial and Capsular Tissues.
abstract: OBJECTIVE
  The present study aimed to clarify individual variations in the cricothyroid joint (CT joint).
  
  
  METHODS
  Using 30 specimens of the CT joint obtained from elderly donated cadavers, we examined the composite fibers of the capsular ligament as well as the morphology of the synovial tissue.
  
  
  RESULTS
  The capsular ligament consistently contained abundant thick elastic fiber bundles on the anterior side of the joint (anterior band) and an elastic fiber-made mesh on the posterior side (posterior mesh). The synovial membrane, lined by synovial macrophages, was usually restricted to the recesses in the medial or inferior end of the joint cavity. Without the synovial lining, elastic fibers of the capsular ligament were subsequently detached, dispersed, and exposed to the joint cavity. We also observed a folded and thickened synovial membrane and a hypertrophic protrusion of the capsular ligament. In six specimens, the joint cavity was obliterated by debris of synovial folds and elastic fiber-rich tissues continuous with the usual capsular ligament. Notably, with the exception of two specimens, we did not find lymphocyte infiltration in the degenerative synovial tissue.
  
  
  CONCLUSIONS
  We considered the CT joint degeneration to be a specific, silent form of osteoarthritis from the absence of lymphocyte infiltration. For high-pitched phonation, the elderly CT joint seemed to maintain its anterior gliding and rotation with the aid of elastic fiber-rich tissues compensating for the loss of congruity between the joint cartilage surfaces. Conversely, however, high-pitched phonation may accelerate obliteration of the joint.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan. Electronic address: putchsan@mail.goo.ne.jp.
authors.forename: Ai
authors.initials: A
authors.lastname: Kawamoto
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Honkura
authors.affiliation: Department of Anatomy, Akita University School of Medicine, Akita, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Suzuki
authors.affiliation: Department of Anatomy, Akita University School of Medicine, Akita, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Abe
authors.affiliation: Department of Anatomy, Tokyo Dental College, Tokyo, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Abe
authors.affiliation: Division of Internal Medicine, Iwamizawa Asuka Hospital, Iwamizawa, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Murakami
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Katori
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001193:Arytenoid Cartilage / Q000033:anatomy & histology* / Q000737:chemistry / Q000502:physiology; D001706:Biopsy; D002102:Cadaver; D003413:Cricoid Cartilage / Q000033:anatomy & histology* / Q000737:chemistry / Q000502:physiology; D004210:Dissection; D004547:Elastic Tissue / Q000033:anatomy & histology* / Q000737:chemistry / Q000502:physiology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D007596:Joints / Q000033:anatomy & histology* / Q000737:chemistry / Q000502:physiology; D008297:Male; D010699:Phonation; D013583:Synovial Membrane / Q000033:anatomy & histology* / Q000737:chemistry / Q000502:physiology; D014831:Voice
keywords: Capsular ligament; Cricothyroid joint; Elastic fibers; High-pitched phonation; Human anatomy; Immunohistochemistry; Macrophages; Synovial tissue