title: Immunohistochemical and histological study of human uncovertebral joints: a preliminary investigation.
abstract: METHODS
  A descriptive cadaveric study.
  
  
  OBJECTIVE
  To investigate the anatomy and innervation of the uncovertebral joint to determine if it is synovial in nature and capable of generating pain.
  
  
  BACKGROUND
  There is controversy with regard to the anatomic and histological makeup of the uncovertebral interface with some authors considering it a joint and others disc tissue. No research has investigated the presence of pain generating neurotransmitters within the uncovertebral cartilaginous and capsular tissue.
  
  
  METHODS
  Tissue from uncovertebral capsule and cartilage was harvested for each uncovertebral surface starting at the C2-C3 to the C6-C7 cervical segment. The tissue was placed in 4% paraformaldehyde fixative, then dehydrated and embedded in paraffin. Ten micron sections were cut through the tissue blocks and mounted on slides. The tissue was rehydrated and either stained with hematoxylin and eosin (H and E) or immunostained with antisera against protein gene product 9.5 (PGP 9.5), substance P (SP), neuropeptide Y (NPY), and calcitonin gene-related peptide (CGRP).
  
  
  RESULTS
  The sample consisted of 2 unembalmed fresh male human cadavers of a mean age of 83 years. Chondrocytes and synoviocytes were identified at the capsular tissue of each uncovertebral interface from C2-C3-C6-C7. Immunoreactivity for PGP 9.5, SP, CGRP, and NPY was observed at all uncovertebral interface levels in capsular tissue.
  
  
  CONCLUSIONS
  The presence of both synoviocytes and chondrocytes has been recorded in the present study, suggesting that the uncovertebral interface is synovial in nature. Immunoreactivity to PGP 9.5, SP, CGRP, and NPY indicates the presence of nerve fibers from both the somatic and autonomic nervous systems. These findings suggest that the uncovertebral joints are potential pain generators in the cervical spine.
authors.affiliation: Department of Rehabilitation Sciences, Musculoskeletal Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Brismée
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Sizer
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Dedrick
authors.forename: Barbara G
authors.initials: BG
authors.lastname: Sawyer
authors.forename: Michael P
authors.initials: MP
authors.lastname: Smith
mesh_terms: D000369:Aged, 80 and over; D018771:Arthralgia / Q000209:etiology / Q000503:physiopathology; D017776:Autonomic Pathways / Q000166:cytology / Q000378:metabolism; D002102:Cadaver; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis / Q000378:metabolism; D002574:Cervical Vertebrae / Q000166:cytology* / Q000294:innervation / Q000378:metabolism; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000166:cytology* / Q000294:innervation / Q000378:metabolism; D017746:Joint Capsule / Q000166:cytology / Q000294:innervation; D007596:Joints / Q000166:cytology* / Q000294:innervation / Q000378:metabolism; D008297:Male; D019547:Neck Pain / Q000209:etiology / Q000503:physiopathology; D009478:Neuropeptide Y / Q000032:analysis / Q000378:metabolism; D009619:Nociceptors / Q000166:cytology / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000378:metabolism; D013373:Substance P / Q000032:analysis / Q000378:metabolism; D013583:Synovial Membrane / Q000166:cytology* / Q000294:innervation / Q000378:metabolism; D043222:Ubiquitin Thiolesterase / Q000032:analysis / Q000378:metabolism
chemical_list: D009478:Neuropeptide Y; C482860:UCHL1 protein, human; D013373:Substance P; D043222:Ubiquitin Thiolesterase; D015740:Calcitonin Gene-Related Peptide