The innervation pattern of the human Achilles tendon: studies of the normal and tendinosis tendon with markers for general and sensory innervation

Cell Tissue Res. 2005 Apr;320(1):201-6. doi: 10.1007/s00441-004-1014-3. Epub 2005 Feb 9.


Pain-free normal Achilles tendons and chronic painful Achilles tendons were examined by the use of antibodies against a general nerve marker (protein gene-product 9.5, PGP9.5), sensory markers (substance P, SP; calcitonin gene-related peptide, CGRP), and immunohistochemistry. In the normal tendons, immunoreactions against PGP9.5 and against SP/CGRP were encountered in the paratendinous loose connective tissue, being confined to nerve fascicles and to nerve fibers located in the vicinity of blood vessels. To some extent, these immunoreactions also occurred in the tendon tissue proper. Immunoreaction against PGP9.5 and against SP/CGRP was also observed in the tendinosis samples and included immunoreactive nerve fibers that were intimately associated with small blood vessels. In conclusion, Mechanoreceptors (sensory corpuscles) were occasionally observed, nerve-related components are present in association with blood vessels in both the normal and the tendinosis tendon.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Achilles Tendon / blood supply
  • Achilles Tendon / injuries
  • Achilles Tendon / innervation*
  • Achilles Tendon / pathology*
  • Achilles Tendon / surgery
  • Adult
  • Antibodies / metabolism
  • Biomarkers / analysis*
  • Biopsy
  • Calcitonin Gene-Related Peptide / metabolism
  • Female
  • Humans
  • Male
  • Middle Aged
  • Substance P / metabolism
  • Ubiquitin Thiolesterase / metabolism


  • Antibodies
  • Biomarkers
  • UCHL1 protein, human
  • Substance P
  • Ubiquitin Thiolesterase
  • Calcitonin Gene-Related Peptide